HomeMy WebLinkAboutReconnaissance Study Of Energy Requirements & Alternatives-Main Report 5-1982FILE COPY
E42/ . OF. 03 im RECONNAISSANCE STUDY OF ENERGY
REQUIREMENTS AND ALTERNATIVES
MAIN REPORT
MAY 1982
ALATNA
ATQASUK
BREVIG MISSION
DIOMEDE
GALENA
GOLOVIN
GUSTAVUS
KARLUK
KOYUK
NEW CHENEGA
RUBY
SAINT MICHAEL
SHAGELUK
Prepared ay: SHISHMAREF
STEBBINS
\ TELLER
UNALAKLEET
YAKUTAT __ ALASKA POWER AUTHORITY -
MATKASOOK
(ATQASUK)
SHISHMAREF
DIOMEDE @
BREVIG ALATNA |
TELLERQ@QMISSION (ALLAKAKET ¢@ eee ALLAKAKET
GOLOVIN wos KOYUK PaiBy
UNALAKLEET FALRBANKS ST. MICHAEL GALENA,
AXA—6TEBBINS
mSHAGELUK
BETHEL Pe ANCHORAGE
NEW CHENEGA
o oe
KODIAK
iP KARLUK:
YAKUTAT
GUSTAVUS CaN
)
LIST OF TABLES
Table Title Page
D.1 Alternative Rankings D-7
E.4.1.1 Waste Heat Availability ........ cee eee ee eee eee E4-5
E.4.3.1 Central Alaska = Solar Energy 2% sccec6 s cccccenus a E4-12
Fel Village Technology Assessment (Sample) .............. F-10
LIST OF FIGURES
Figure Title Page
Frontispiece
C.1 Energy Balance Logic Diagram .......... ce cece e eee C-3
El.1-1 Simplified Coal-Fired/Steam Power Plant ............. E 1-2
E1.2-1 Wood-Fired Steam Power Plant Flow Diagram ........... E 1-7
E1.3-1 Geothermal Power Production By the Flashed
Steam Process .... eee ccc cece eee cece cette eens E 1-11
E2.2-1 Simple-Cycle Gas Turbine Plant .................00 08. E 2-5
E3.1-1 Hydrologic CYCNe scscans sqnassscnwscnosaswensmonaswes E 3-2
E3.2-1 Wind Turbine Generators ........ cece ee cece eee ee eee E 3-7
£4.1-1 Jacket Water and Exhaust Waste Heat Recovery System . E 4-2
E4.1-2 Jacket Water Waste Heat Recovery System ............. E 4-3
E5.1-1 Clean Fuel Gas From Coal for Power Generation ....... E 5-2
E5.3-1 Biogas Géferation sccscscssscccnnvewwsss naqenseewesia E 5-8
E6.1-1 Generalized Binary Cycle 1... .. cece eee eee ce eee eee E 6-2
A - INTRODUCTION
A_-_ INTRODUCTION
A large proportion of remote Alaskan community energy needs is met with
oil fuels shipped into the villages. This use of oil fuel is based upon
convenience and cleanliness, but comes at no small price. Oi] derived
energy has become expensive in Anchorage and other major cities of the
U.S., particularly for heating. When the costs of transporting oil to
remote areas are added, oil supplies in small communities become very
high priced.
Some rural villages in Alaska receive No. 2 fuel oil at prices
approaching or exceeding $3.00 per gallon, compared to typical city costs
of $1.25 per gallon. This oi] is often used to heat homes, schools and
community buildings, and to run the village diesel electric generators.
Numerous residences in the state require over 200 gallons of fuel for
heating in the coldest winter months. In some locations, the cost of
diesel generated power used by residents exceeds $1.00/kWh and in a few
cases approaches $2.00/kWh. Fuel costs are a significant portion of the
cost of diesel generated power.
Some communities depend totally on oi] because no other resources are
available or potential resources are undeveloped for various reasons.
Other communities use locally available fuels such as wood extensively,
but still require substantial quantities of oi] fuels. All users of oil
based technologies are subject to world market prices and the risk of
high price escalation rates.
The high costs and risk of oi] heating and power production are problems
commonly recognized by rural Alaskan residents and are being addressed by
the Alaskan Energy Reconnaissance Study Program. The objective of
studies in this program is to identify possible energy technologies or
fuel sources which can supply community electricity and heating needs at
lowest cost. Emphasis is being given to methods which reduce or displace
the need for oi] in Alaskan communities.
The report which follows documents one of several Village Energy
Reconnaissance studies authorized by the Alaska State Legislature and
performed under the direction of the Alaska Power Authority.
The work was carried out by Acres American Incorporated, a consulting
engineering firm, with assistance from Environmental Services Limited, an
environmental and sociocultural study firm, and Hanscomb Associates, a
cost estimating and control firm. All companies have offices in
Anchorage.
B - BACKGROUND
B-1
SECTION B - BACKGROUND
B.1 - Utility System Need and Objectives
Existing Alaskan bush utility systems provide services at relatively high
cost to the consumer (compared to urban costs for the same services) and
residents seek improvement of the situation. The problem of high cost
utility services has plagued communities in all parts of the world
for centuries. Until the last hundred years, only adequate supplies of
water and fuel for heating and cooking at acceptable cost (as well as
sewer and garbage systems in large communities) were of common concern.
Recent changes in technology and society have added electricity to the
list of necessities.
The objective of the first and all succeeding central utility systems was
to provide needed services at a far lower cost than could be achieved by
an individual acting alone. The central utility approach generally
involves a sizeable initial investment combined with large reductions in
operating costs to produce a lower overall monthly cost to the user.
Whether government or privately owned, their purpose is to provide a
service to a group of “individuals" at equal or greater reliability and
lower cost.
The user generally does not care who owns or operates the utility
service. Even in small towns, few users take much interest in the
operation of the utility unless they have reason to believe that they are
paying an improperly large portion of their income for the basic service.
In discussions between village residents and reconnaissance field team
members, it was noted that the residents' concerns are almost universally
that the service be available when needed and that it be at lowest
possible cost in terms of his time and money. These are the criteria of
the customer and the objectives of the system, and should be used to
evaluate any contemplated changes to a utility system.
B.2 - Incorporating Changes in a Utility System
Once the need for change is identified, there are three paths which can
be taken: first, return to the old ways (abandonment); second, make do
with whatever economy measures are possible and make gradual improvements
as funds become available (conservation and upgrading); and third, invest
in major improvements or replacements (start over). The major difference
between selection of the three alternatives is financial - the
availability of initial capital.
B-2
The abandonment approach is often unacceptable, as the alternate method
is often an even more costly use of money and time. The conservation and
upgrading approach is often used as a compromise on full replacement and
becomes increasingly necessary as centralization increases.
The approach of major renovation/replacement is not often economically
justified for centralized systems. For relatively new systems, this
generally involves write off of existing but inadequate equipment. Such
losses rarely can be absorbed by a utility operation, as virtually all of
their funds are invested in the existing equipment. Adoption of the
third approach also rarely involves replacement with a new technology
much cheaper in cost; otherwise, it would likely have been installed in
the first place. Thus, immediate replacement generally, but not always,
results in greater initial costs charged to the consumer to cover both
premature retirement losses on the old equipment and the cost of the new.
In many cases the benefits of the new system do not become obvious for
several years.
The problems facing the utility system managers in evaluating proposed
changes generally lie in defining how much capacity will be demanded by
customers at any given time, and what "costs" should be compared in
making decisions regarding equipment to be used. Underestimation of
capacity needs will soon be confirmed, and may deny some users the bene-
fit of the system as well as constrain growth and development of the
local economy if such growth is desired. Overestimation will burden the
customers with higher costs than were truly needed, but will allow
economic growth. To this end, government often subsidizes overcapacity
for the long term growth and benefit of a region.
B.3 - Centralized vs. Individual Heating Systems
For some basic utility services a central system approach may be more
costly and less desirable than individual systems. The most obvious
example is residential heating. Centralized (district) heating is a
reliable and cost effective method in some densely populated areas of the
world. However, the piping systems are exceedingly expensive for most
suburban and rural areas, with the result that virtually all homes are
individually heated by oil, gas, electricity, wood, coal, the sun, or
some combination of the above.
B-3
B.4 - Choice of Fuels
Oil and gas are highly desirable fuels for residential heating because of
their cleanliness and ease of use. In recent years oi] and gas prices
have escalated significantly for a variety of reasons, and little relief
is in sight for the next several decades. As a result, homeowners are
switching to what are perceived to be cheaper fuels. These "cheaper"
fuels may be cheaper in the short term, but many have long term impacts
which are potentially severe if ignored. As an example, in many areas
the burning of wood is becoming more widespread. In areas with sparse
forests and slow-growing trees, the annual demand for firewood is greater
than can be supported by sustainable growth in the immediate village
area. As a result, those people wishing to heat with wood must continu-
ally go farther and farther to gather it. Widespread indiscriminate
cutting of forests can decrease wildlife habitat.
The value of leisure time can be great enough to alter the choice of
fuels for home heating. Such fuels as wood generally require lower
monetary expenditure, but require more of the user's time to gather, cut,
split and transport the energy source than would be required to obtain
oil or gas supplies. For some people, the self sufficiency and control
of their energy supplies achieved by cutting wood, combined with the
physical exercise are sufficient to offset the time required. For
others, the dangers of wood cutting and the physical strength and time
requirements are major deterrents, and they choose to suffer the cost
increases of the existing systems.
B.5 - Utility Planning in Alaskan Villages
The provision of electricity and heating services to Alaska bush villages
involves the same basic problems as those found in Anchorage, the lower
48 state communities, or foreign countries. The differences lie in the
importance of time and money to the village residents, the resources
available, the residents' specific objectives regarding standards of
living and economic growth, and the types of systems which presently
exist in the villages.
C - METHODOLOGY
C-1
C _- METHODOLOGY
The objective of the work covered by this report has been to identify
energy sources, conversion technologies, or conservation measures (if
any) which will reduce the cost of electric energy in the villages under
study. The work required to meet this objective involves a large number
of data collecting, evaluation and decision steps. The process is
outlined in this section to illustrate both the wide range of information
considered and the inherent limitations of these preliminary studies.
The background work required was organized into the following separate
tasks:
data collection
energy balance preparation
energy use forecasts
energy resource evaluation
energy system plan development
cost estimation
economic evaluation
The results of these tasks were reviewed to determine possible options
village by village. Activities within these seven tasks are, therefore,
key to the conclusions, and are described in this section.
C.1 - Data Collection
Energy use data were collected from a variety of sources. The most
important sources were the villages being studied, which were each
visited by a minimum of two people on the study team. Field data were
supplemented by documents available from various Alaska state agencies,
reports of previous investigations in related topics, and discussions
with fuel and electric utility companies.
Resource and technology information was gathered from previous
reconnaissance studies and resource assessments, manufacturers and
equipment vendors.
C.2 - Energy Balances
Once the required data were collected, energy balances were prepared
using an approach illustrated in Figure C.1. An energy balance is an
assessment of all energy resources used (wood, oi], coal, hydroelectric,
wind, etc.), and the uses to which the energy is put (space heating,
C-2
transportation, electric power generation. etc.) in a village. The
energy balance data can be represented handily by a drawing showing the
flow of energy from its source through its ultimate uses. Such drawings
are included in each village report.
As can be expected, the quality and amount of available data varied from
village to village. Consequently, calculations were not necessarily
performed in the same sequence for each village (as indicated by the
direction arrows). At times, due to a lack of data, calculations were
worked "backwards" to either confirm the available data or check
assumptions made before proceeding with the analysis.
The objective of the energy balance task was to identify fuel type,
quantities, and end uses in each community. Characteristically, the fuel
types included fuel oi], wood, gasoline, and propane. The main end uses
considered were space heating, water heating, electric power generation,
transportation, and cooking. Energy usages for heating and power
generation were subdivided into residential use and commercial and
government use. Gross energy input, net heat requirement, and electric
power output were estimated. The following illustrates the procedures
used in preparing the energy balances.
C.2.1 - Annual Fuel Consumption
Fuel Oi]
Wholesale purchase records for fuel oi] were the primary source for
data to determine the annual volume of fuel oil consumed. This
included electric utilities, schools, and commercial stores.
Normally the annual oil consumption of an electric utility was
known; but, in those cases where unknown, it was estimated based on
the annual electrical requirement assuming a particular fuel
consumption rate based on diesel generator size. Those units rated
less than 100 kW were assumed to produce 7 kWh/gal; 100 - 250 kW,
8 kWh/gal; units larger than 250 kW, 10 kWh/gal. The annual fuel
oil re of schools was either known or calculated using the
Retherford+ model for determining space heat requirements in bush
schools, and the energy required for hot water heating was added.
The annual sales volume of the commercial fuel oi] dealers was
either known or estimated.
Annual fuel oi] energy was computed by summing the annual volume of
each source and multiplying by a standard energy content of 138,000
Btu/gallon.
1 R. W. Retherford Associates, Division of International Engineering,
Anchorage, Alaska.
TOTAL WHOLESALE CONSUME RS USES
ENERGY PURCHASERS
USE & HOT WATER HEATING HOT WATER HEATING TYPE CZ Skies y
SPACE HEATING SPACE HEATING NET RK GAG SCHOOLS 1sgooo | BTU/GAL. fees) [ vseru | COMMERCIAL ! ELECTRIC [Ca HOT WATER HEATING FUEL OIL rity (ELECTRIC HEATERS) WASTE HEAT ‘APPLIANCES, LIGHTS
ETc.
TOTAL NET
HOT WATER HEATING (RUNNING WATER) Govt AND OTHER USES
STORES HOT WATER HEATING | 9*0.65 | WASHETERIA, HOT
WASHETERIA, WATER WATER HEATING TANK - GROSS 470.65 NET A+0.35 ‘SPACE HEATING GROSS| SPACE HEATING NET 970.65 vesj> (SPACE HEATING GRosg b> (Space HEATING NET
WATER) 0.65 (HOT WATER HEATING
GROSS NO R fi HOT WATER HEATING
NET
a*065) 9*035 SPACE HEATING NET
GOv'T AND 420.35 6 17*10 BTU/ CORD a COMMERCIAL SPACE HEATING GROSS SPACE HEATING NET
NO 97035 [RESIDENCE S} {RUNNING GROSS ENERGY vse | HOT WATER HEATING NET
YES SPACE HEATING NET
0.35
SPACE HEATING NET
COOKING AND HOT
WATER RESIDENCES
TRANSPORTA’ wate (Hrs ] EEE BTU/GAL. LEGEND
» INDICATES DIRECTION OF COMPUTATION
<< INDICATES COMPUTATION CAN BE IN BOTH DIRECTIONS, DIRECTION TAKEN DEPENDENT ENERGY BALANCE LOGIC DIAGRAM ON AVAILABLE DATA. IF SUFFICIENT DATA WERE AVAILABLE CALCULATION WAS
PERFORMED IN BOTH DIRECTIONS AND SERVED
TO CROSS-CHECK RESULTS.
CONTRIBUTION TO SPACE HEAT
FIGURE C.1
c-4
Gasoline
Annual gasoline consumption was either obtained from the commercial
dealers or estimated. An energy content of 125,000 Btu/gallon was
used to compute total energy use.
Wood
The annual consumption of wood was determined in a number of ways.
In cases where estimates of the average annual consumption per
resident were considered good, this number was multiplied by the
number of residences using wood. (Since some residents burn both
wood and oi], a percentage of the estimated village use of wood was
used if appropriate.) In villages where it was difficult to
estimate the average household consumption of wood, estimates for
another village were used and multiplied by the ratio of the number
of heating degree days between villages to obtain the annual
consumption of the study village. This method was only used where
home styles were compatible. In villages which used both wood and
fuel oi] for residence heating and for which the annual household
consumption of fuel oi] was considered a good estimate, it was
assumed that the net heating requirements would be the same for a
similar house heated with wood. The number of homes heating with
wood were then multiplied by the net heating requirement. An
efficiency of 35 percent was used to determine the gross heat input.
Heat content of wood was assumed to be 17 million Btu/cord.
Propane
Propane is normally used for cooking and hot water, but most of the
energy actually goes into space heating. The annual usage of
propane was either supplied by the local commercial dealers or
estimated on a per household basis. In determining the usage of
propane, an energy value of 19,500 Btu/pound, and a capacity of 100 pounds/bottle were used.
C.2.2 - Electric Power Generation
Electric power generation is almost exclusively by diesel
generators. Major consumers are schools, residences, government and
commercial buildings. In some villages, there is no centralized
distribution network.
Useful Energy - Waste Heat
In cases where data for both the annual net generation in kWh and
annual fuel consumption existed, both the useful energy and waste
heat were calculated by taking both the net generation and fuel
consumption and converting to equivalent Btu. The difference was
considered waste heat. Where one number was missing, it was
calculated on the fuel consumption assumptions stated in Section
C.2.1. In this way, both waste heat and useful energy could be
determined.
C-5
Useful Energy
Useful energy was subdivided into electrical energy used by resi-
dents and that used by schools, commercial buildings and government
facilities. Consumption per household was normally based on the fraction of energy sold to the residential sector. Where this
information did not exist, it was estimated based on anticipated
household appliances. Not all residents were on line in villages
with a centralized system. For those residents who heated their
water using electric heaters, an efficiency of 100 percent was
assumed.
Consumption per commercial/government building was determined in a
similar fashion.
C.2.3 - Schools
All schools considered used oi] for space heating and water heating
and some used oil for power generation. If the annual oil
consumption of a school was known, this data was used to compute the
annual space heating usage. If the consumption was not known, it
was estimated using the Retherford model.
Hot Water Heating
If a school had shower facilities, the hot water heating
requirements were determined assuming: three showers per week during the school year for each high school student, 15 gallons of
hot water per shower, a final hot water temperature of 140°F, and an
oi] hot water heater efficiency of 65 percent.
Space Heating
If the total fuel consumption was known, gross hot water heating
usage was subtracted to determine the gross space heating usage. An
oil burner efficiency of 65 percent was used to determine the net
heat requirement.
In cases where the Retherford model was employed, the net heat
requirement was determined and an efficiency of 65 percent was used
to obtain the gross space heat.
C.2.4 - Commercial and Government
Commercial and government fuel consumption consisted of both oi] and
wood, although oi] was by far the most significant. Fuel oi] used
by the commercial and government sector, exclusive of schools, was
normally estimated as a percent of the commercial sales. In some
instances the villages had their own oi] storage tanks and were able
to supply estimates of annual consumption for school and government
buildings.
C-6
Water Heating
Energy required for government and commercial hot water heating was
considered for washeteria and water tank water heating only. Other
government and commercial uses were considered minimal and
neglected. If the village had a washeteria, water heating
requirements were determined assuming: two loads of clothes per
week per household, 20 gallons of hot water per load, a hot water
temperature of 140°F, and an efficiency of 65 percent. If the
washeteria had shower facilities, then it was assumed that residents
took one shower each week, consuming 15 gallons per shower.
If the town heated its water tank to keep the water from freezing,
the estimated energy requirements were provided by the water system
operators or village leaders. Where community water system
operators kept records of the fuel needed to heat water, those
records were used.
Space Heating
Gross space heating was calculated by taking the total energy input
and subtracting hot water and other user energy consumptions. Gross
space heat per building was then estimated based on the number of
buildings and the relative requirements of government and commercial
buildings as determined from the field observations.
Using efficiencies of 35 percent for wood heating and oil pot
burners, the net space heating requirements were computed. In
buildings with gun-fired furnaces, an efficiency of 65 percent was
used. :
In most circumstances, the net space heating requirements were also
determined by taking the net residential space heating requirements
and applying a conversion factor to determine commercial and
government building requirements. Net space heating requirement was
then divided by the gross space heating to yield an efficiency.
C.2.5 - Residences
Residences are generally heated with oi] or wood. In homes that use
propane for cooking and heating hot water, most of the energy from
combustion of the propane was assumed to contribute to the net space
heat requirement and was, therefore, taken into account in the
heating fuel calculation.
Water Heating
Only the communities of Karluk, Unalakleet and Yakutat had extensive
residential running water systems. Accordingly, their hot water
heating requirements were different from the other communities. For
these villages, the following assumptions were made to compute the
water heating energy usage: daily per capita consumption of 10
gallons, hot water temperature of 140°F, and efficiencies of 65
percent for oil fired hot water heaters and 100 percent for electric
hot water heaters.
In the communities that did not have running water, a per capita
consumption of 1 gallon of hot water per day was assumed. Since it
is normal practice to heat water on a stove, the energy that did not
go into heating the water was included as space heat.
Space Heat
Calculations for net space heat requirements were complicated by the
fact that more than one house type might exist in a community, that
some homes heated with both oil and wood, that in some homes propane
use contributed to space heat, and that village wood use had to be
estimated since there are no bulk dealers of wood.
In villages where wood was used, the equivalent percentage of
villagers using wood was estimated. This accounted for the fact
that some homes burned both wood and oi]. One approach to
estimating the annual average household consumption of wood was
through personal interviews with the townspeople and comparison with
other villages.
If the net energy usage of an oil consuming house could be
accurately estimated by assuming that the net energy usage of an oil
consuming and a wood burning house were the same, then an efficiency
of 35 percent was applied to determine gross energy input. The
total annual energy input was then computed by multiplying the
household totals by the equivalent number of wood burning homes.
Space heating requirements were determined by subtracting the water
heating requirements from total energy usage on both a village and
household scale.
Residential consumption of fuel oi] was estimated from total retail
sales less a percentage for commercial sales. This volume was then
distributed over the equivalent number of residences using oi] to
determine household consumption. If the village had running water,
gross hot water heating requirements were subtracted to obtain the
gross space heating usage. Net oil space heating usages were found
using efficiences of 35 percent for oi] pot burners and 65 percent
for gun-fired furnaces. For villages without running water, net
water heating requirements were subtracted from net energy uses to
determine the net space heating requirement. (This subtraction was
generally a minor percentage of the total energy.)
In some cases the number of barrels of oil consumed by a household
was known. This was used to determine the gross energy usage of a
household. If the village had running water, the gross energy for
hot water heating was subtracted to determine the gross space heat
usage. The net space heat requirement was computed using an
appropriate efficiency. The gross energy usage of a household was
multiplied by the number of residents using oil to determine the
total residential consumption. This could be compared to the
estimated residential sales from commercial dealers if that data
were available. If it were not, total commercial and government
consumption could be estimated and summed with residential sales to
determine fuel sales.
In villages where housing types and numbers could be identified,
gross and net space heating requirements were calculated. Homes
using propane were considered as having the heat from the propane
contribute to the net heating requirement.
The results were assembled into a diagram of energy use for each of
the villages, as presented in later sections.
C.3 - Energy Forecasts
Energy use forecasts were developed based upon information provided by
village residents regarding possible population and economic growth,
comparison of energy use and living standards between villages, and
regional growth indicators. This information was combined to generate
population growth projections, which were then used to project heat and
power needs. Individual projections were prepared as follows:
C.3.1 - Residential Electricity Forecast
From the energy balance the present residential electrical demand
and annual electrical energy consumption per household were
determined. Using the population and dwelling units forecast,
residential village demand and energy use were determined. Annual
residence percentage increases in demand and use were estimated.
These increases varied depending on saturation of the community in
terms of electrical appliance use.
If households in a community were not connected to the utility
system, it was assumed that within five years all households would
be. Hookups were assumed to occur on linear basis annually. New
housing units were assumed to be connected to the utility from the
onset.
C.3.2 - Commercial and Government Electricity Forecast
Energy use and demands of existing schools were assumed to remain
constant even though there may be slight increases in student
population. Energy use of commercial and government buildings was
assumed constant. Forecasted new units were assumed to have the same
electrical consumption as existing buildings.
C-9
C.3.3 - Thermal Energy Forecast
Residences
Net residential energy requirements per household were determined in
the energy balance. The total community residence requirement was
obtained by multiplying the forecasted number of units by the net
residence requirement. New units were assumed to be more efficient
and an appropriate adjustment factor was applied.
Commercial and Government
Net energy use of existing schools, commercial and government
buildings was assumed constant throughout the planning period. New
units were assumed to have the same efficiency as existing units.
C.4 - Energy Resource Evaluations
Energy resources (wood, coal, water, wind, sun, etc.) were evaluated
largely on a site by site basis. Inputs to these evaluations included
previous resource assessments, study documents, residents' descriptions
and estimates of nearby resources and observations.
C.5 - Energy System Plan Development
A minimum of three development plans for power production were to be
prepared based upon the results of the activities described above. This
was approached in two steps:
(1) Screening and selection of appropriate technologies
(2) Development of plans
The screening activities were carried out through application of the
following screening methodology and criteria.
C.5.1 - Screening Methodology and Criteria
The screening methodology incorporates a three part evaluation of
the various technologies as applied to each village. The evaluation
uses a weighted value system with ranking developed according to
information available and requirements of the village under study.
An overall score is determined for each candidate technology, using
the following relationship based upon the ranking scores determined
for each of three categories:
C-10
Score = (A +B) XC
(0 to 100) 2.2
Where A = total technical factor score
B = total cost factor score
C = combined resource availability score
Technical Factors
Technical factors can be grouped into three sub-categories -
reliability, construction requirements and environmental
impacts.
Cost Factors
Cost factors can be separated into initial costs for
installation of the system (capital cost), recurring costs of
ownership and operation (operation, maintenance, and annual
expenses), and fuel costs.
Resource Availability
The selection of any particular technology to supply heat or
power is completely dependent upon the availability of
supporting resources. Included in this category are the
fuel/energy source, the operating staff, technical and
community support services, transportation network and
communications systems required.
A relative evaluation scale is applied to each subcategory for each
technology. Values are assigned based upon the findings documented
in the technology assessments (contained in Section E) and site
specific determinations.
The evaluation scales are based upon the following considerations:
Technical Factors
Reliability
Reliability refers to the level of confidence a system provides to
the customer that his needs will be met at all times. Reliability
of a given system is affected by operating conditions, maintenance
policies and completeness of the initial installation, and
individual component system reliabilities.
Performance capability and design maturity are additional factors
associated with components (particularly the generating plant)
contributing to system reliability.
C-11
Equipment capacity and performance also affect reliability. An
electric generation system of inadequate capacity or incapable of
responding adequately to a load change will (if properly protected)
shut itself down whenever demand exceeds capability. Undersized
heating systems will not heat a home adequately in severe
conditions. In both cases the customer has an unreliable system.
Availability
A major factor in electric system reliability is equipment
availability. Availability refers to the percent of maximum
possible time that a system is capable of operating as expected.
Equipment or system failures of a hardware nature are commonly
referred to as forced outages, while scheduled maintenance is a
planned outage. Both reduce availability. Availability and outage
data are difficult to obtain for most Alaskan village applications,
primarily because the required data are not well documented.
Information from other parts of the U.S. is of questionable
applicability given the particular difficulties of Alaskan
operations.
Building heating systems are usually of very simple design so as to
achieve very high availability. Problems are readily detected and
generally very easy to correct. Thus availability of common types
of heating systems is generally not a great concern.
The Importance of Design Maturity
Forced outages due to mechanical failure typically are more frequent
and longer in duration for new equipment designs with limited
operational history. Initial design errors often only surface once
the design reaches the point of commercial installation and service.
Replacement with new but inadequately designed parts rarely solves
such problems, necessitating redesign and retrofit by either the
manufacturer or the customer. This may entail an extended outage
for a relatively simple redesign, or a number of part replacements
until a major redesign can reach the point where proper parts or
assemblies can be built, shipped and installed. Thus, design
maturity, as evidenced by number of units in operation and hours or
years of operation since design/redesign, is of significant
importance to predicting reliability.
System Complexity
As a system becomes more complex (i.e., increasing numbers of moving
parts and/or less modular construction), the possibility of failure
also tends to increase. This can be offset by greater redundancy
and quality control, but only when accompanied by increased initial
costs for production and installation. More elaborate maintenance
procedures are often a secondary result.
C-12
Alaskan bush conditions, for the most part, are not conducive to
using highly skilled maintenance personnel to perform complex
procedures with high levels of support equipment. Small villages
are generally remote - largely accessable on a year-round basis
only by small planes as permitted by weather. Although on-site
personnel may be given extensive training, their newly acquired
skills often depend upon availability and use of extensive support
equipment. Such requirements are expensive and, therefore, less
desirable unless the expense is a minor portion of overall costs.
Ideally, equipment selected for use should need an absolute minimum
of daily maintenance, and should require only very occasional
maintenance on a scheduled basis by highly skilled service
technicians.
Support Requirements
A major attraction of diesel systems is the limited training
required for operation and regular maintenance procedures. Service
support does, however, require spare parts inventories, machine shop
facilities, and trained mechanics and electricians to perform
repairs, replacements and overhauls on equipment. Unless located
close by, this support structure also requires a transportation
system capable of delivering the service personnel, parts and tools
required on short notice.
Spare parts inventories for any given technology can become a major
investment as complexity, physical size and uniqueness of the
selected equipment increases. Large investments in spare parts are
undesirable for either the customer or the equipment supplier.
Investment required is totally a function of system complexity,
desired reliability, technological maturity, and operating
policies.
Reliability Characteristics
The performance aspect of reliability is for the most part only
applicable to electric generator technologies. Heating systems
generally work either in a full on/full off mode, or are manually
adjusted by the user (i.e., wood stove). Electric generator system
load response characteristics are of interest here. Ability to
accept sudden changes in customer loads affects the selection of
unit capacity for small systems.
Ranking Range: 0-5 points
Construction Requirements
Construction in remote areas of Alaska involves major limitations
on availability of manpower, equipment transport, availability and
C-13
usefulness of large earth moving and erection equipment, load
bearing capability of soils, weather conditions and support
services.
Diesel engine systems require a minimum of construction labor to
install, minimal excavations, foundations and protective structures,
and minimal lifting equipment to put the equipment in place.
Therefore, system generating capability can be installed within a
matter of weeks, or less, and be ready to supply energy to the
distribution system.
Construction skill requirements and availability, field housing,
transportation for manpower materials and equipment needed,
geotechnical requirements and construction season must be considered
for the various approaches to providing electric power or elaborate
methods of building heating.
Ranking Range: 0-2 points
Environmental Impacts
Environmental impacts can be categorized according to the following
areas:
animal habitats displacement
land use
air emissions
noise
water quality and use
visual impact
electromagnetic field interferences
solid and liquid waste disposal sa DAN 0m Ideally, power generation and heating should have minimum impact on
any of the above areas. In reality, each technology has impacts of
various severity levels in each area.
Diesel generating systems presently in use in the remote villages
have varying impacts according to location. However, diesel
characteristics can be generalized to some extent to provide a
comparison baseline.
Most systems are housed in modest buildings adjacent to the
community, thus displacing few, if any, wild animal habitats and
contributing little to the requirements for land. Air emissions are
produced as a result of the combustion process, and significant
noise is produced and emitted to the surroundings. Water use is
minimal, as the cooling systems are sealed and rarely drained.
Visual impact is limited to the area of the protective structure -
the stack plume, fuel oil drums or storage tanks, and the building
itself (separate from the distribution cables which would exist with
any production methods). Electromagnetic field interferences are
c-14
minimal unless a defect exists in the generating system. Waste
disposal is primarily limited to waste oil, parts boxes and cartons,
and scrap parts, and may or may not be confined to the area of the
powerhouse.
Ranking Range: 0-2 points
Maximum Total Ranking Points - Technical Factors: 9
Cost Factors
Electric users rates are a direct function of both initial cost and
annual costs of operation. Selection of the equipment to be used is
generally made on the basis of minimum expected cost based upon a
selected group of factors. Whereas private citizens in some
instances exclude initial cost (often the case with heating
systems), prudent decisions can be only made when initial cost,
system life and operating costs are all examined.
Initial Investment
Initial costs include the costs of the basic equipment, shipping,
erection and startup. These are subject to the variability of field
conditions and labor availability in the Alaskan bush areas.
Initial costs used must, therefore, be risk adjusted. Normal
practice for installation cost estimates is to provide a contingency
fund based upon the perceived cost uncertainty range.
equipment
shipping
erection
support facilities
personnel support during construction
mobilization/demobilization AnPwWwWNrr Ranking Range: 0-4 points
Fixed Annual Costs
Fixed annual costs include (at a minimum) the annual payments of
principal and interest to cover the cost of the initial
installation. These payments are generally determined by the
expected lifetime of the equipment. Initial investment and
operating lifetime can generally be predicted for mature techno-
logies. As annual fixed costs are highly dependent upon operating
life expectancy, unexpectedly short life can result in serious
problems in financing replacement equipment and in providing
sufficient revenues to pay off creditors who financed the initial
installation.
C-15
Operating Costs
Operating costs can be subject to considerable uncertainty, with a
resulting effect on user rates. If relatively small in proportion
to fixed annual costs (as in the case of hydroelectric or wind
power), operating cost uncertainty has minimal effect. Operating
costs for diesel engine systems tend to represent a large proportion
of costs for small units, but their impact diminishes as unit size
increases. Rural Alaskan conditions also tend to increase annual
operating costs, because of the difficulties of obtaining service.
Operation, maintenance, fixed annual costs include the following:
operating labor
supplies and materials
replacement parts and maintenance labor
maintenance support services
replacement operator training
insurance
depreciation
debt service
general administrative WOONAAPWNMHE Ranking Range 0-5 points
Fuel Costs
Fuel costs and use as defined by system efficiency, or costs
associated with gathering and transport of energy source.
Ranking Range 0-3 points
Maximum Total Ranking Points--Cost Factors: 11 |
Resource Availablity Factors
No technology is applicable to a situation if its resource
requirements are unavailable. For example, a geothermal power plant
cannot be considered if no source of geothermal heat exists in the
region.
Consequently, resource availability is a critical parameter separate
from the technical and cost considerations. Both natural and human
resource needs must be considered. These include energy sources
(fuels, etc.), skilled labor needs and availability, and the
existence of a support structure for construction supplies,
equipment and human services (schools, medical facilities, etc.) and
operating support (communications, roads, etc.).
Natural resources required for some technologies either do not exist
at site or are available in various quantities. Wood based
technologies, for example, are subject to various levels of resource
C-16
availability. Sufficient tree stock may exist to allow heating of
all homes for 100, 50, 20, 11 or 2 years for example. The same
considerations apply to local coal deposits and to wind resources as
represented by average windspeed. Technologies that are otherwise
attractive are useless if adequate supplies of the basic energy
source do not exist. Availability also applies to imported fuels
such as diesel oi], propane and gasoline, but is generally a more
direct function of acceptable purchase price levels.
The resources associated with social and economic development can be
provided if nonexistent at present, but success of an installation
is relatively assured if the required skills and services are
readily available.
Natural Resources
Ranking Range: 0-9 points
Economic and Social Resources
Ranking Range: 0-2 points
A set of criteria for determining point scores has been developed
for each of the above categories, as presented on the following
pages.
Maximum Total Ranking Points--Resource Availability Factors: 1]]
C-17
RANKING SCALE CRITERIA
Technical Factors
Reliability 0-5 points
5 points
4 points
3 points
2 points
1 point
0 points
mature technology, highly reliable, service
support readily available, parts kept in stock.
mature technology, generally reliable
(occasional outages), service support readily
available.
mature technology, generally reliable, weak
service support system (delays foreseen for many
types of parts or service).
commercial technology; intermittent availability
or poor service support (outages can be expected
to last weeks or months).
developing technology expected to be commercial within 5 years; intermittent availability and
poor service.
immature technology.
Construction Requirements 0 - 2 points
2 points
1 point
0 points
minimal site preparation, foundations,
structures and construction time required (less
than 1 year).
significant site construction required -
foundations, erection of structures;
construction time 1-5 years.
extensive on site construction required,
construction period 5 years or more.
Environmental Impact 0 - 2 points
2 points
1 point
0 points
negligible environmental impact on or near
site.
a) significant impact on air or water quality,
or b) significant waste quantities for disposal,
or c) significant land use alteration.
significant impacts in at least 2 of the above
categories.
Cc-18
Cost Factors
Investment Cost 0 - 4 points
4 points electric - cost per kilowatt of expected
reliable capacity or capacity useable in the
next ten years is between $500 and $1,000
heating - initial cost per resident is less than
$1,000.
3 points electric - cost per kilowatt is between $1,000 -
$3,000
heating - initial cost is $1,000 to $2,000 per
residence.
2 points electric - cost per kilowatt is between $3,000 -
$5,000.
heating - initial cost is $2,000 to $3,000 per
residence.
1 point electric - cost per kilowatt is between $5,000 ‘and $10,000
heating - initial cost is $3,000 to $5,000 per
residence.
0 points electric - cost exceeds $10,000 per kilowatt of
capacity.
heating - cost exceeds $5,000 per residence.
Operational Cost 0 - 4 points
4 points annual operating and maintenance labor expenses,
incremental overhead expenses and replacement
parts and supplies do not exceed $5,000/GWh
produced.
3 points same as above except $20,000/GWh produced.
2 points annual labor costs, incremental overhead, and
parts and supplies do not exceed $50,000/GWh
produced.
1 point annual costs (as above) do not exceed
$100,000/GWh produced.
0 points annual costs exceed $100,000/GWh produced for
heating;
1 GWh = 3.4 X 109 Btu delivered.
C-19
Fuel Costs 0 - 3 points
3 points
2 points
1 point
0 points
Fuel cost is governed by fuel conversion
efficiency.
Annual costs for labor, equipment replacement
and depreciation, and local transport expenses
are a maximum of 25 percent of equivalent oil
fuel price in present $; price is independent of
world market.
costs of labor to obtain fuel, equipment
replacement and depreciation and expenses of
transport and preparation are a maximum of 50
percent of oil fuel price with minimal
sensitivity to outside market price forces.
costs of obtaining energy source and expenses of
transport and preparation are approximately
equal to oil fuel, at present, or are 50 percent
or more of oil fuel costs and tied to oil fuel
escalation (diesel base case).
costs are equal to or exceed oil fuel price,
escalate at approximately the same rate due to
high interdependence, or system is less
efficient than existing oi] fired design.
Resource Availability
Natural Resources 0 - 9 points
9 points
7 points
5 points
3 points
1 point
0 points
extensive resources readily available to the
village (0-5 miles).
extensive resources readily available, but may
require importation by air or barge, or are
located 10 to 20 miles away by ground
transport.
sufficient resources available in region or from
outside to maintain operations for 20 years or
to support large portion of required capacity.
modest resources available (5-10 years supply
for less than 50 percent of needed capacity), or
resources available on intermittent basis.
minimal resources available (1-5 years supply
for less than 50 percent capacity).
no resources available.
C-20
Socioeconomic Resources 0 - 2 points
2 points labor force with required skills exists in area;
existing communiciations, transportation,
safety, health and educational systems are
adequate to accommodate needs associated with
the technology.
1 point labor force, communications, health,
transportation safety and educational systems
available in village.
0 points inadequte social/economic structure exists to
support development.
An example of the use of these criteria is provided in Section F of
this report.
C.5.2 - Development of Plans
Heating options were examined and technologies considered appropriate
were selected and recommended for consideration. Potential savings
have been identified on a generalized basis only, as actual heating
loads of individual buildings vary greatly even within a community.
The planning activities therefore concentrated on identifying any
alternatives suitable for each village.
Electric power generation/supply plans were developed for each
village. Wholesale overhaul of the existing system was not an
approach used for any of the communities studied. The existing
system was examined in light of load projections to identify optimum
timing of installations using alternate technology. System capacity
requirements were determined based upon having adequate reserve
capacity to cover peak load in the event that the largest unit went
out of service in any given year. The resulting plans are described
in later sections.
C.6 - Cost Estimation
Cost estimates for each plan were based upon information from various
sources: oooo°o manuf acturers
published reports
vendors
in-house data
transportation rate schedules
Costs were adjusted for site specific conditions.
C-21
C.7 - Economic Evaluation
Economic evaluation of development plans was performed in accordance with
the standard procedures of the Alaska Power Authority for reconnaissance
and feasibility studies performed in fiscal year 1982. These procedures
essentially require a simplified present worth of minimum revenue
requirements approach based upon a real financial discount rate of 3
percent and real oi] escalation at 2.6 percent.
The techniques used produce annual or average costs of energy which are
not comparable to any other costs for energy unless also calculated by
the same methods. Actual costs paid by community residents will, in
general, be higher than the rates derived for the analysis, because of
the following:
1. Consumers pay the costs associated with actual operation of a utility
in an economy experiencing significant inflation. The engineering
evaluations performed are based upon long term cost evaluation
principles which recognize the impact of inflation. Engineering
evaluations are, therefore, based on modified long term costs, to
insure that the system selected will minimize the customers cost.
The rates customers presently pay for the use of the equipment or
methods being studied will be similar at present, but in all
likelihood higher than shown on the tables of this report.
2. The analysis techniques ignore costs which are common to all possible
methods of providing energy. In the case of electricity, these
include the cost of village distribution systems (where they already
exist), metering, residential service, billing and administrative
costs and utility general staff. The customer's bill does include
these costs on a pro-rated basis. Establishment of proper rates for
these common items comes under the jurisdiction of the Alaska Public
Utilities Commission and is not within the scope of these studies.
These items also increase the rate actually paid by the customer in
comparison to the values tabulated in this report.
The costs derived in this report are directly comparable only to other
costs contained in the report or to costs derived for other villages in
Fiscal Year 1982 Reconnaissance Studies.
A standard economic life is assigned to each different alternative. They
are:
Gasification and Waste Heat Recapture Equipment = 10 years
Solar, Geothermal & Wind Turbines = 15 years
Electric Transmission Lines = 20 years
Diesel Generation = 20 years
Gas Turbines = 20 years
Rankine Cycle Turbines = 25 years
Combined cycle Turbines = 30 years
Steam Turbines = 30 years
Hydroelectric Projects = 50 years
C-22
Economic projections for all alternatives in each village will be
extended to the alternative having the longest life. For instance, the
economic projections of a village having hydropower and diesel generation
alternatives will be carried to 50 years in both alternatives.
Similarly, if an alternative has a subsystem coming on line in later
years which extends the economic life of the entire system, all
alternatives will be carried to that economic life.
D - SUMMARY OF FINDINGS OF ALL VILLAGES
D-1
D - SUMMARY
D.1 - General
Each of the eighteen villages investigated in this study was visited to
determine on a first-hand basis conditions regarding energy use and
village development. The results indicate that the problem of high
energy costs in the villages cannot be solved by simple substitutions of
technology. Improvements are possible which can produce cost reductions
in all but a few villages. Immediate savings can be noticeable in some
cases but will primarily be seen to develop over many years.
Significant improvements may be achievable in some villages through
simple building heating method improvements. Better sealing of
structures, without any change in fuels presently used, and use of low
cost yet more efficient furnace designs are expected to produce results
immediately. Such changes will produce substantial results as heating
generally dominates all energy use in the villages.
Major reductions in the quantity of oil used to generate electric power
will be difficult in most villages. Whatever savings are possible
generally will have little immediate impact on total energy use or costs
for oi] fuel imports. Careful system planning on a villagewide basis,
combined with coordinated operation of generators can noticeably improve
operating efficiency and reduce costs. Likewise, it becomes imperative
that each village or owner examine their maintenance and operation
procedures to insure that an effective, continual preventive maintenance
program is in place. Short of such a program, premature equipment
failure and major replacement costs can be expected. Diesel engine
generators will remain the primary source of power in nearly all villages
studied through the year 2000. Unfortunately, the rate of technical
development of those alternatives capable of replacing diesel is not
likely to be sufficient to assist most villages.
Several villages have been identified as strong candidate site areas for
renewable resource based technologies. Renewable technologies can
supplement diesel generation, reducing oi] fuel requirements. In some
isolated cases, it is possible that hydroelectric power, a renewable
resource, could completely eliminate dependency on diesel generation
except for emergency backup purposes. Passive solar heating home design
techniques appear worth considering for southeastern villages, although
normal weather conditions limit the results which can be expected.
General improvements in the design and construction of building
insulation systems can most easily provide significant reductions in
energy consumption. Photovoltaic systems do not appear attractive for
residential power, but will continue to find specialized application.
Geothermal resources reportedly exist near Ruby and Brevig
Mission/Teller. However, regional demand and distance between resource
and load provide little, if any, incentive for development.
D-2
Many villages have sufficient wind or hydropower potential to warrant
further study (Recommendations 3 and 4).
Some villages would appear to have regionally available fuels which, if
used, could reduce dependence on “imported" oi] fuels. Wood is already
used in many locations.
Waste heat recovery and energy conservation appear attractive in nearly
all villages. Conservation requires a small investment in training as to
simple heat conserving improvements for rural homes. Lifestyles should
not be noticeably altered as a result. Waste heat recovery from diesels
to heat community structures appears attractive in nearly all villages.
Fuel conversion technologies (coal, wood and biomass gasification) do not
appear sufficiently developed for rural application at this time. Wood
gasification may, however, find application in the next decade in those
locations with good wood resources.
D.2 - Individual Village Summaries
0.2.1 - Alatna
Alatna is a very small settlement of eight families located
directly across the Koyukuk River from the larger village of
Allakaket. The village is presently powered by one small 3.5 kW
(4.7 hp) air cooled diesel generator. Because of its size and
distance from Allakaket, there are no viable alternatives to their
situation. However, as Alatna is virtually a part of Allakaket, a
reconnaissance of that larger community was also conducted. There
is clearly potential for equipping the new Allakaket diesel
generators at the school with a waste heat recovery system.
D.2.2 - Atqasuk
Atqasuk is a developing community south of Barrow presently powered
by diesel generators and heated with oil furnaces. There are
presently plans to construct a transmission line from Barrow to
Atqasuk to serve their future needs. The transmission line is
clearly desirable from social, environmental and technical
standpoints. It is also more economical than diesel generation
with waste heat recovery. Heating alternatives include use of
diesel waste heat and coal stoves. Coal is abundantly available
near the village, but use of this resource requires development of
a community mine.
D-3
0.2.3 - Brevig Mission
Brevig Mission is a community on the Seward peninsula presently
generating power with oi] fueled diesels and heated by oil and wood
stoves. The school buildings presently utilize a waste heat
recovery system. Wind energy may be feasible as a supplementary
means of power generation. Wood resources are extremely restricted
on land, and driftwood supplies are unreliable.
D.2.4 - Diomede
Diomede Island, located in the Bering Straits, is totally dependent
at present on oi] fuels. Wind power potential appears good enough
to be considered as a source of nearly continuous power.
Establishment of an anemometry site atop the island of Little
Diomede is recommended. Diesel waste heat recovery is presently
used by the school in this community.
D.2.5 - Galena
Galena is located on the Yukon River due west of Fairbanks. Power
generation is by diesel engine generator, while heating is fueled
by imported oil] and local wood. The city is large enough for
consideration of gas turbine generators provided there is some
assurance of adequate support skills and power demand; an
evaluation indicated this approach to be more expensive than
present methods. Hydropower from Kalakaket Creek does not present
sufficient seasonal power production. Galena is also expected to
benefit from a regional hydro development on the Melozitna River,
but such a project requires development of mining interests or
other unidentified major loads in the area to justify its
construction.
Diesel waste heat recovery is already utilized in Galena, although
the system has yet to prove itself. Heating will continue to be
based upon wood and oil] resources. Improved stove designs may
reduce costs of heating some structures.
D.2.6 - Golovin
Golovin is located on the northern shore of Norton Sound. Electric
power is by diesel generation, and heating is by oil and wood
stoves. Waste heat recovery from the diesel is presently used to
heat the school. The present system appears to be the most viable
solution. Further analysis of wind conditions must be accomplished
to properly evaluate wind potential.
D.2.7 - Gustavus
Gustavus is located in the Sealaska area approximately 50 miles
west of Juneau. The population is highly dispersed. Electric
generation at present is primarily by individual generators for
residences and a commercial generation plant serving community
service buildings and the airport. Heating is by wood, oil, and
passive solar. The results of the evaluation indicate that a small
local hydroelectric site appears attractive. This site could
supply a centralized system as well as the nearby facilities of
Glacier Bay National Park at a savings over present costs.
D.2.8 - Karluk
Karluk is located on the western end of Kodiak Island. Electric
power is presently provided by diesel generator sets, with heating
provided by wood and oi] stoves. Wind appears to be a potential
method of generating power on a supplemental basis. A hydro site
is also available. The lack of a central distribution system
renders these approaches unattractive. Increased use of wood for
heating is recommended, as is the establishment of anemometry
stations to define the wind resource.
0.2.9 - Koyuk
Koyuk, located on Norton Bay, is presently served by a central
diesel generator plant and heated by wood and oil stoves. No
alternatives appear attractive, unless waste heat recovery from the
diesels can be exploited.
0.2.10 - New Chenega
New Chenega does not exist at present, but is planned for
construction 100 miles southeast of Anchorage on Evans Island.
Electrical generation methods appropriate for the site are diesel
and hydro. Alternative heating methods are diesel waste heat, and
wood.
D.2.11 - Ruby
Ruby is located on the Yukon River approximately 50 miles east of
Galena. Power is provided by diesel generator, with heating by
wood and oil stove. Waste heat recovery appears to be an
attractive alternative heating method. Construction of a regional
hydro plant on the Melozitna River could benefit Ruby. However,
such an alternative requires more thorough review at a regional
level to establish overall benefit to cost comparisons.
0.2.12 - Saint Michael
Saint Michael is located on the southeastern shore of Norton Sound.
Power production is by diesel generator, with heating by oi] stove.
Diesel waste heat recovery appears potentially attractive, as does
wind turbine generation. Anemometry stations should be established
to more fully define available wind resources.
D.2.13 - Shageluk
Shageluk is located on the Innoko River north of Aniak. Power is
provided by diesel generator, with heating by wood and oil stoves.
Waste heat recovery appears attractive for community buildings.
0.2.14 - Shishmaref
Shishmaref is located on Sarichef Island in the Chukchi Sea. Power
is by diesel generator and heating is by oil stove. Waste heat
recovery from the diesel plant appears attractive. Wind may be
attractive as well, but the wind resource requires evaluation.
Anemometry studies are recommended.
D.2.15 - Stebbins
Stebbins is located near Saint Michael. Power is diesel generator
supplied, and heating is by oil as well as by wood supplies
unavailable to Saint Michael. The use of waste heat recovery also
appears attractive in Stebbins if the AVEC generators are
relocated. Sufficient wind potential may be available to warrant
further study.
0.2.16 - Teller
Teller is located near Brevig Mission, and is also powered by
diesel generator and heated with oil stoves. Waste heat recovery
is a potential alternative for Teller, as is wind. Anemometry
studies are recommended.
0.2.17 - Unalakleet
Unalakleet is located on the eastern shore of Norton Sound. Power
for the city is provided by diesel electric generation sets, with
heat provided by oi] and wood stoves. Wind turbine generation
appears worth investigating beyond the present small scale
programs. Waste heat recovery from the generating plant appears
attractive.
0-6
D.2.18 - Yakutat
Yakutat is located on the coast approximately 400 miles east
southeast of Anchorage. Electric power is provided by diesel
generator sets, and oi] and wood are used as heating fuels.
Possible generating alternatives for Yakutat include wind turbines,
gas turbines, and a small wood fired steam electric plant.
However, none of these alternatives were found to be as economic as
the existing diesel system. Waste heat recovery from the diesel
generators is attractive, as is greater reliance on wood as a
heating fuel.
Table D.1 summarizes the findings of the study. Energy
alternatives for each village are ranked based upon cumulative
present value of annual costs as prescribed by the APA evaluation
method. Technologies which produce greater present value for equal
energy production than the existing system are not attractive, as
consumer costs would be increased.
D.3 - Further Recommendations
The results of this study indicate that consumer energy bills can be
reduced over the coming decades in many of the study villages. All
villages will benefit from reduction of infiltration losses and selective
improvements in building insulation. Simply put, this means gaps should
be plugged around doors and windows, at joints in walls, and in many of
the new houses within the under floor structure. This will produce
significant energy savings in many of the homes visited by field
personnel. Additional measures could include increased use of arctic
entrances and double glazed windows or storm windows. Air leakage was
caused in some cases by uneven settling of foundations on new homes.
The heating energy used in a home could also be cut significantly in many
villages through the use of more efficient wood or oi] stoves. These
need not be expensive. For example, easy to use kits are available for
conversion of oil drums to high efficiency wood stoves. Most homemade
stoves observed are cheap but inefficient, thereby causing the owner to
use far more wood than necessary.
Recommendation No. 1 - Conservation
Information regarding simple conservation improvements should be provided
to residents, preferably through a program of energy use "workshops" led
by native people from the region trained to use and teach these methods.
Such a program is recommended as the simplest way to provide significant
savings in village energy costs.
TABLE D.1 - ALTERNATIVE RANKINGS
VILLAGE 1 2 3
Alatna Base Case "B" combining Alternative "A" intertying Base Case "A" using existing
Allakaket and school district Alatna with Allakaket and dispersed power systems for
power systems and using waste school district power system Alatna, Allakaket, and school
heat recovery of Base Case "B"
Net Present Value $3,660,000 Net Present Value $3,791,000 Net Present Value $4,149,000
Over Economic Analysis Period Over Economic Analysis Period Over Economic Analysis Period
1982 through 2041 1982 through 2041 1982 through 2041
Atqasuk Alternative "A" intertying Base Case using planned diesel None Available
Atqasuk with Barrow power
grid
Net Present Value $17,863,000
Over Economic Analysis Period
1982 through 2002
power station with waste heat
recovery
Net Present Value $23,609,000
Over Economic Analysis Period
1982 through 2001
Brevig Mission Base Case using existing diesel
system equipped with waste heat
system.
Net Present Value $1,319,000
Over Economic Analysis Period
1982 through 2001
Alternative "A" using existing
diesel system with waste heat
system plus 100 kW wind turbine.
Net Present Value $1,457,000
Over Economic Analysis Period
1982 through 2009
None Available
Diomede Alternative "B" using two 250 kW
wind turbines to displace major-
ity of diesel generation as well
as heating oil.
Net Present Value $958,000
Over Economic Analysis Period
1982 through 2015
Alternative "A" using one 50 kW
wind turbine to supplement exis-
ting diesel/waste heat system.
Net Present Value $2,067,000
Over Economic Analysis Period
1982 through 2015
Base Case using existing diesel
system equipped with waste heat
system.
Net Present Value $2,127,000
Over Economic Analysis Period
1982 through 2015
TABLE D.1 - ALTERNATIVE RANKINGS
VILLAGE 1 2 3
Galena Base Case using existing Alternative "A" using hydro Alternative "B" using hydro
diesel system with waste heat power at Kalakaket Creek power at Melozitna River. Plan
recovery equipment could be most economic if
electricity demand dramatically
increases
Net Present Value $20,220,000 Net Present Value $22,463,000 Net Present Value $46,263,000
Over Economic Analysis Period Over Economic Analysis Period Over Economic Analysis Period
1982 through 2041 1982 through 2041 1982 through 2041
Golovin Base Case using existing diesel Alternative "A" using 100 kW None Available
system with waste heat recovery wind turbine to supplement
equipment. existing system
Net Present Value $1,859,000 Net Present Value $2,018,000
Over Economic Analysis Period Over Economic Analysis Period
1982 through 2007 1982 through 2007
Gustavus Alternative "B" using Base Case using existing Alternative "A" using central
hydroelectric power at Falls dispersed power generation diesel power generation
Creek
Net Present Value $3,920,000 Net Present Value $4,550,000 Net Present Value $4,922,000
Over Economic Analysis Period Over Economic Analysis Period Over Economic Analysis Period
1982 through 2035 1982 through 2035 1982 through 2035
Karluk Base Case using existing Alternative "A" using central- Alternative "B" using central
decentralized generators
Net Present Value $2,539,000
Over Economic Analysis Period
1982 through 2035
ized diesel generators
Net Present Value $2,687,000 Over Economic Analysis Period
1982 through 2035
diesel equipment with waste heat
system
Net Present Value $2,822,000 Over Economic Analysis Period
1982 through 2035 8-0
VILLAGE
Koyuk
TABLE D.1 - ALTERNATIVE RANKINGS
1
Alternative "A" using existing
AVEC system plus waste heat
equipment
Net Present Value $2,391,000
Over Economic Analysis Period
1982 through 2006
2
Base Case using existing AVEC
system
Net Present Value $2,630,000
Over Economic Analysis Period
1982 through 2006
3
Alternative "B" using 100 kW
wind turbine to supplement
diesel generation
Net Present Value $2,552,000
Over Economic Analysis Period
1982 through 2006
New Chenega Alternative "B" using hydro-
electric plant to supplement
diesel system
Net Present Value $3,401,000
Over Economic Analysis Period
1982 through 2035
Alternative "A" using diesel
generators equipped with waste
heat recovery equipment
Net Present Value $4,068,000
Over Economic Analysis Period
1982 through 2035
Base Case using diesel
generation
Net Present Value $4,750,000
Over Economic Analysis Period
1982 through 2035
Ruby Alternative "A" using the
school generator building for
village power generation and
waste heat equipment
Net Present Value $5,081,000
Over Economic Analysis Period
1982 through 2041
Base Case using existing city
diesel system
Net Present Value $5,970,000
Over Economic Analysis Period
1982 through 2041
Alternative "C" using
hydroelectric power at the
Melozitna River
Net Present Value $12,644,000
Over Economic Analysis Period
1982 through 2041
Saint Michael Alternative "A" using exis-
time AVEC system plus a waste
heat recovery system.
Net Present Value $3,413,000
Over Economic Analysis Period
1982 through 2014
Alternative "B" using existing
AVEC system plus a 100 kW wind
turbine used to supplement
Net Present Value $3,688,000
Over Economic Analysis Period
1982 through 2014
Base Case using existing
AVEC system
Net Present Value $4,045,000
Over Economic Analysis Period
1982 through 2014
TABLE D.1 - ALTERNATIVE RANKINGS
VILLAGE 1 2 8
Shageluk Alternative "A" using existing Base Case using existing AVEC Not Available.
AVEC system plus waste heat system
recovery system
Net Present Value $1,989,000 Net Present Value $2,374,000
Over Economic Analysis Period Over Economic Analysis Period
1982 through 2001 1982 through 2001
Shishmaref Alternative "A" using existing Alternative "C" using existing Alternative "B" using existing
AVEC system plus waste heat AVEC system plus waste heat re- AVEC system plus 100 kW wind
recovery system covery system plus 100 kW wind turbine to supplement diesel
turbine to supplement diesel use use
Net Present Value $4,247,000 Net Present Value $4,358,000 Net Present Value $5,042,000
Over Economic Analysis Period Over Economic Analysis Period Over Economic Analysis Period
1982 through 2001 1982 through 2001 1982 through 2001
Stebbins Alternative "B" using existing Alternative "A" using existing Base Case using existing AVEC
AVEC system plus waste heat AVEC system plus 100 kW wind system
recovery system turbine
Net Present Value $2,707,000 Net Present Value $3,214,000 Net Present Value $3,282,000
Over Economic Analysis Period Over Economic Analysis Period Over Economic Analysis Period
1982 through 2009 1982 through 2009 1982 through 2009
Teller Alternative "B" using existing Base Case using existing diesel Alternative "A" using existing
diesel generators and waste heat
recovery system plus 100 kW
wind turbine to supplement
diesel use
Net Present Value $2,830,000
Over Economic Analysis Period
1982 through 2001
generation
Net Present Value $2,917,000
Over Economic Analysis Period
1982 through 2001
diesel system plus expended
waste heat recovery system
Net Present Value $3,024,000
Over Economic Analysis Period
1982 through 2001 OL-d
TABLE D.1 - ALTERNATIVE RANKINGS
VILLAGE 1 2 s)
Unalakleet Alternative "A" using existing Base Case using existing Alternative "B" using existing
UVEC system plus waste heat UVEC system UVEC system plus two 100 kV
recovery system wind turbines to supplement
diesel use
Net Present Value $12,181,000 Net Present Value $15,660,000 Net Present Value $15,912,000
Over Economic Analysis Period Over Economic Analysis Period Over Economic Analysis Period
1982 through 2005 1982 through 2005 1982 through 2005
Yakutat Alternative "A" using existing Base Case using existing YPC Alternative "B" using existing
YPC diesel system plus waste
heat recovery system
Net Present Value $13,750,000
Over Economic Analysis Period
1982 through 2012
diesel system.
Net Present Value $18,630,000
Over Economic Analysis Period
1982 through 2012
YPC diesel system plus two
200 kW wind turbines to supple-
ment diesel use
Net Present Value $18,838,000
Over Economic Analysis Period
1982 through 2012
LL-d
D-12
Recommendation No. 2 - Make Specialized Services and Information Available to Residents
Establish a "consultant pool" of consulting firms or individual
specialists which are available to the regional corporations or villages
on an as needed basis. People with specialized knowledge could be made
available to study and provide workable solutions to specific energy
problems common to a significant number of residences or several villages
in a region. Such a group could work very closely with the regional
corporation and the native energy specialists trained to carry out the
recommended conservation program.
Recommendation No. 3 - Define Wind Resources More Completely
Establish appropriate wind anemometry stations at Diomede, Karluk,
Stebbins/Saint Michael, Unalakleet, Yakutat, New Chenega, Golovin, Koyuk,
Brevig Mission/Teller and Shishmaref. (Some of these villages are
presently targeted for such programs. )
Recommendation No. 4 - Evaluate Local Hydro Potential
Proceed with more detailed hydroelectric feasibility studies at Gustavus
and New Chenega. The Melozitna River does present potential energy for
Galena, Ruby and the surrounding area. However, this should be studied
at a regional level to determine its feasibility. Early indications
suggest the availability of substantially more potential than is needed.
Hydropower on this river clearly is not justified to serve only one
village. Prior to undertaking the hydro studies, the objectives and
purpose of a feasibility effort, and the various alternatives to be
considered should be explained to the residents and their support should
be obtained. The “owner” of the proposed mining venture should be a
participant in any studies of the Melozitna.
Recommendation No. 5 - Power Systems Consolidation
The school districts should consider transfer of power generation and
supply to some other entity primarily responsible for utility services,
thereby eliminating, in many cases, duplicate facilities and services.
This should eliminate excessive costs and will probably increase power
system reliability.
D-13
Recommendation No. 6 - Periodic Review
Each village or regional council should continually monitor the
development of the communities in light of these studies. More rapid
development than anticipated can increase the number of options open to
many villages for reduction of costs.
Energy costs are high in most of the villages studied when compared to
the amount of money spent by residents of Anchorage. Heating is the
major fuel use, and costs can be reduced by cutting down on heating needs
and more efficient use of fuels. Locally available fuels should be used
whenever the heat they can produce far exceeds the energy in the gasoline
used to gather them (i.e., to power snow machines). Electric power costs
are "high" primarily because the villages' needs can only support small
systems. The findings indicate that power cost reductions will be small
as few options are suitable for use in place of diesel engine generators.
Proper operation and maintenance and good system planning are key to
holding down costs in any electric utility system, and should receive
continuous attention for the village systems.
APPENDIX
E - TECHNOLOGY PROFILES
E - TECHNOLOGY PROFILES
INTRODUCTION
The technology profiles which follow are an attempt to provide a
consistent, appropriate, data base from which to draw when preparing
alternative plans for the individual villages. These technology profiles
contain general information on different types of power producing
technologies and attempt to assess their general applicability to Alaskan
uses. Data on siting requirements, costs, and efficiencies are made
available on a consistent basis for use later in alternative plan
development. Much of the data contained in this section was taken from a
report prepared in 1981 by the Robert W. Retherford Division of
International Engineering Company! as suggested by the Alaska Power
Authority. Their data was reviewed for its suitability for this report and
revised where appropriate. Cost estimates developed in that work were
updated to 1982 levels. Costs are expressed in estimated December 1981
dollars.
Although at least several data sources are available for each technology,
the data generally is quite variable (often based on incompatible
assumptions) and, perhaps more important, does not often apply to systems
suited for Alaskan use. Data discrepancies for the so-called alternative
energy technologies are also strongly influenced by the simple lack of
experience in constructing and operating facilities utilizing these
technologies.
EXPLANATORY NOTES
1. Factors that cause differences in electrical generating plant capital
costs per kW include:
project scope
regulatory requirements
local cost variations
plant size
single versus multiple unit plants
construction time
interest rates
1 International Engineering Company Inc., "Reconnaissance Study of
Energy Requirements and Alternatives for Buckland, Chathbaluk, Crooked
Creek, Hughes, Koyukuk, Nikolei, Red Devil, Russian Mission, Sheldon
Point Sleetmute, Stony River, Takotna and Telida," 1981.
E-2
2. The availability factor is used as a measure of reliability and is the
percentage of time over a specified period (typically one year) that
the power plant was available to generate electricity. Credit for
availability is not given if the plant is shut down for any reason.
3. Net Energy as used here is typically referred to as the "heat rate" in
the case of electric generation and is expressed as the ratio of Btu in
to kWh out in this case. For direct heat application cases, this ratio
is Btu in to Btu out.
E 1-1
E.1 - STEAM-ELECTRIC TECHNOLOGIES
E.1.1 - Direct Fired Coal for Electrical Generation
E.1.1.1 - General Description
Thermodynamic and engineering processes involved:
Coal is ground to readily combustible size and mechanically
loaded into a boiler furnace where it is burned to provide heat
to convert incoming water to steam. The steam is then expanded
in a turbine which drives a generator to produce electricity.
Figure E1.1-1 shows a simplified steam power cycle.
Current and future availability
Steam plants account for the majority of electrical generation in
the United States today. Although steam plants can accommodate a
wide range of loads, U.S. economies of scale indicate that the
cost per unit increases sharply in sizes below about 50 MWe.
It should be noted that European coal-steam generation units are
employed in the less-than-10 MWe range.
E.1.1.2 - Performance Characteristics
Energy output
Quality - temperature form
Electricity
Quantity
Unit sizes available up to 1,300 MW. Sizes appropriate to
Alaska are typically 5-50 MWe; 1 MW. (1,000 kWa).
Dynamics - daily, seasonal, annual
Coal-fired steam plants are typically used to generate power
on a continuous basis at nearly constant output without
respect to time of year.
Reliability
STEAM HEADER
MNT TOT TTT LTT
EXHAUST OUT
TURBINE
BOILER
GENERATOR
COAL f i ———>,
STORAGE PILE
STEAM COOLING
CONDENSER FLUID
oe
CONDENSATE FEED PUMP. (1)
SIMPLIFIED COAL-FIRED/STEAM POWER PLANT
FIGURE E1.I-!
E 1-3
Availability Factor
National statistics for investor-owned utility plants in the 60
to 89 MW size range (the smallest size documented) show typical
unit availability of 90 percent. Availability tends to drop as
unit size increases. Back-up required to allow both planned and
unplanned maintenance during unavailable periods.
Storage requirements
Typical fuel in storage for major coal-fired plants is sufficient
supply for 90 days of operation. For village areas, up to 12
months worth of coal storage may be required to guarantee
continuous supply irrespective of weather.
Thermodynamic efficiency
Up to 35 percent for large units; much lower efficiency expected
for 10 MW scale units
Net Energy
10,000 - 17,500 Btu input per kWh of output
En 1.3 = Costs
Capital Investment for 1 to 10 MW plant
Estimated range of $3,000 to $5,000/kW, excluding transmission
line. Cost highly variable with plant capacity and location.
Operation
50-100 $/kW/yr for small plants (less than 10,000 kW) such as at
Kot zebue
Fuel cost for $65/ton, 6,800 Btu/1lb, and 17,500 Btu/kWh works out
to 8.4¢/kWh (Kotzebue using Chicago Creek coal).
Maintenance and replacement
2.5 percent of initial investment per year in real dollars for
maintenance
2.1 percent of initial investment per year for replacement
(sinking fund @ 3 percent for 30 years).
Economies of scale
E 1-4
Economies of scale favor larger scale plants than normally
considered for Alaska, particularly with respect to coal handling
facilities. (New plants in the lower 48 are typically of 1,000
MWe size with two 500 MW units.) Full-time operator
requirements also favor large plants to reduce costs per kilowatt
hour generated.
E—.1.1.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
Coal plants require space for storage of fuel. Cooling water is
not mandatory for Alaska conditions as air cooled condensers can
be used with small plants. If the plant is sited at a mine, fuel
transport problems are reduced; storage of a month's fuel use may
be adequate.
Resource needs
Renewable
NA
Non-renewable
Typical Alaskan coal ranges from 6,500 to 8,000 Btu per
pound.
Limestone or dolomite will also be required if a scrubber
system is installed. Water may be required for condenser
cooling and for the scrubber system if a wet type design.
Construction and operating employment by skill
Requires highly skilled construction and operating personnel.
Environmental residuals
Solid wastes: include slag, bottom ash, scrubber sludge.
Gaseous wastes: NOx, SO,.
Current environmental regulations regarding sulfur dioxide
emissions from conventional coal-steam plants require abatement
processes which limit emission quantities from units with eneray
inputs equal to or exceeding 250 million Btu per hour (roughly
equivalent to a 15 to 20 MW unit).
Coal-fired plants emit the following, as yet unregulated,
atmospheric pollutants: toxic and carcinogenic trace elements,
radionuclides, and organic and metal-organic compounds. Other
Eere2
£— 1-5
considerations include impact of mining, transport and storage of
fuel, and coal pile run off.
Health or Safety Aspects
See above. Additionally, typical Alaskan coal is quite prone to
spontaneous combustion. Regular turnover of the stockpiled coal
by bulldozers would be needed to prevent this problem at
locations with extensive storage. Coal allowed to remain
undistrubed for only a matter of a few days can catch on fire.
E.1.1.5 - Summary and Critical Discussion
Cost per million Btu or KWh
Smal] Alaskan plants will generate at costs of 10-15¢/kWh at 50
percent capacity factor with $65/ton coal. Use of $130/ton coal
increases costs by 5 to 9 ¢/KWh depending upon unit efficiency.
Resources, requirements, environmental residuals per million Btu or
kWh.
For coal at 6,800 Btu per pound and plant at 17,500 Btu/kWh, 2.6
pounds of coal are needed per kWh. NO, emissions are about 0.15 1bs/million Btu.
SO, emissions are about 0.067 1bs/million Btu (with
precipitator on stack).
Particulate emissions are about 0.006 Ibs/million Btu.
Solid wastes are about 10 percent of fuel quantity burned.
Critical discussion of the technology, its reliability and its
availability.
In general, the conventional boiler-fired steam turbine system is
the most economic and technologically developed system available
to the power industry. Available coal-fired boiler sizes limit
minimum plant size to perhaps 5 MWe, however. Lead time is
significantly longer than for diesel or gas turbine
installation.
- Wood-Fired Steam for Electrical Generation
E.1.2.1 - General Description
Thermodynamic and engineering processes involved
Wood can be directly fired in traveling grate or stoker type
steam boilers to provide steam for a conventional steam turbine
cycle. Boilers designed for wood are significantly larger in
size than an equivalent coal-fired boiler, and much larger than
E 1-6
an oil-fired unit. Figure £1.2-1 shows a wood-steam plant flow
diagram.
Current and future availability
Existing commercial systems are roughly in the 1-50 MW range. A
number of U.S. manufacturers produce wood-fired boiler designs
suitable for generating electricity in the 250-1,000 kW range.
E.1.2.2 - Performance Characteristics
Energy output
Quality - temperature, form
Electricity
Quantity
Plant sizes vary from 0.5 to 50 MW, although most economies
of operation suggest a minimum size plant of 5 MW
Dynamics - daily, seasonal, annual
Future supplies can be adversely impacted by: economic
competition, distance of supplies, and needs for sustained
forest yield levels.
Reliability
Availability factor
Availability expected to be similar to a coal-fired plant; 80 to
90 percent.
Storage requirements
As for a coal plant, ninety days of fuel is typically stored; up
to 9 months storage is required if climate only permits a few
months of harvesting and transportation.
Thermodynamic efficiency
up to 21 percent
Net energy
16,000 - 30,000 Btu/kWh
WOOD & [TRANSPORT
STACK
EMISSION
CONTROL
TURBINE
CONVEY, STORAGE CONVEY BOILER
PIPING PREPARATION GENERATOR
WATER | CONDENSER TRASH ASH Pre l HANDLING
COOLING
FLUID
WOOD FIRED STEAM POWER PLANT FLOW DIAGRAM
FIGURE a Z-l
E 1-9
growth of timber in interior Alaska, it can be seen that
over the normal 30-year life of a wood-fired steam plant,
about 1,000 acres (1-1/2 square miles) would be affected.
Non-renewable
NA
Construction and operating employment by skill
Requires highly skilled construction and operation personnel.
Environmental residuals
Solids: Ash particulates
Air: SOy, NOx
Impacts of harvesting
Considerations include impact of cutting, transport and storage of fuel, and wood pile run off.
Risk of spontaneous combustion
Injury rate of wood cutting
E.1.2.5 - Summary and Critical Discussion
Cost per million Btu or kWh
Resources, requirements, environmental residuals per million Btu or KWh
Per above, at least two pounds of dry wood are required per kWh;
three to four pounds/kWh is more probable. NO, emissions are about 0.25-1.18 1bs/million Btu
SO, emissions are about 0.07-0.18 1bs/million Btu
Particulate emissions are about 0.02 lbs/million Btu
Residual ash from wood firing is not classified as a hazardous
waste; firing wood waste actually decreases the amount of solid
waste.
Critical discussion of the technology, its reliability and its
availability
Although dry wood (at about 8,000 Btu/pound) has about the same
potential heat content as much of Alaska's coal, most wood is
sufficiently moist to reduce this heat value by 40 to 50 percent.
In addition to the moisture content, the relative volume-to-
weight ratio of wood is disadvantageous as compared to coal, with
consequent increased material handling requirements. Also, as
compared to coal, the fuel gathering and transportation processes
result in the expenditure of significantly greater amounts of
energy.
Wood, a relatively clean burning fuel, is more suitable for
smaller steam power plant than is coal.
E 1-10
E£.1.3 - Geothermal - Electric (Flashed Steam)
E.1.3.1 - General Description
Thermodynamic and engineering processes involved
Geothermal power production has been proposed or demonstrated for
areas with natural steam, hot water or dry hot rock resources.
The well-known Geysers facility in California involves use of
natural steams. A facility at Heber, California is demonstrating
the use of hot water throttled to produce steam by flash
vaporization. Other methods involve extraction of heat from
geothermal water using binary cycles.
Geothermal electric generation in Alaska would be by the flashed
steam or binary processes. Binary conversion technology is
discussed generically in another profile; the flashed steam
technology is profiled here as shown schematically in Figure
E— 1.3-1. The flashed steam process applies to liquid dominated
geothermal reservoirs such as those thought to exist in Alaska.
Hot liquids are brought to the surface and partially converted to
steam in flash vessels where the fluids undergo pressure
reduction. The separated steam component is used to power a
steam turbine-generator and spent and separated fluids are
reinjected into the earth to minimize potential subsidence
problems.
Current and future availability (Flashed Steam)
Not currently in commercial practice in the United States, but
over 140 MW in operation in foreign countries. U.S.
environmental restrictions are much more severe, in general.
E.1.3.2 - Performance Characteristics
Energy output
Quality - temperature form
Electricity
Quantity
Economic California plant units are in the range of 35-50 MW.
A pilot plant at Heber, California is 10 MW size.
Dynamics - daily, seasonal, annual
Geothermal electric plants are generally used for base
(continuous) loads.
GENERATOR
COOLING TOWER
Poe
MAKE UP AAA c
FLASH
VESSEL
DIRECT CONTACT BRINE CONDENSER REINJECTIO PUMP CIRCULATING WATER PUMP
CONDENSATE
en
TO REINJECTION
WELLS
BLOWDOWN
PUMP
FROM PRODUCTION WELLS GEOTHERMAL POWER PRODUCTION BY THE
FLASHED STEAM PROCESS
FIGURE E1.3-1
E 1-12
Reliability
Need for back-up
No back-up required for a proven resource, although standby
wells are common. :
Unit back-up required in the event of outage.
Availability factor
70 percent availability factor on equipment expected.
Storage requirements
No special storage required; reservoir provides essentially
unlimited storage.
Thermodynamic efficiency
Up to 12 percent (10-12 percent typical) overall plant
efficiency; turbine efficiency alone is around 22 percent.
Net energy
27,000 - 34,000 Btu/kWh
E.1.3.3 - Costs
Capital
$1,400/kW installed (California 50 MWe)
Assembly and installation
N/A
Operation
N/A
Maintenance and replacement
N/A
Economies of scale
Economies of scale are generally advantageous over about 30 MWe
and are increasingly disadvantageous below that size.
E.1.3.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
E 1-13
Typically, 3-5 acres of land with geothermal resource are
needed for each MWe; 90 percent of this area is open space
between wells and plant facilities.
Resource needs
Renewable
Assuming geothermal is considered a renewable source, the
fluid would have typical characteristics of 340°F @ 115
psia.
Non-renewable
N/A
Construction and operating employment by skill
Highly skilled construction and operating personnel are
required.
Environmental residuals
Air: Hydrogen sulfide gas (H2S) has been a problem at
California plants.
Cooling water quantities: a function of quality of geothermal
water used
Health or safety aspects
Noise pollution can be a problem, with levels greater than 100 dB
for well venting and related activities. Other considerations
include disposal of spent fluids, HS ("rotten egg" smell), and
possible surface subsidence.
E.1.3.5 - Summary and Critical Discussion
Cost per million Btu or KWh
9.84¢/kWh has been reported as levelized busbar cost from a 50 MW
California plant. Alaskan costs will be highly site dependent.
Resources, requirements, environmental residuals per million Btu or
kWh
Solid wastes are a function of geothermal fluid composition and
can be zero.
E 1-14
Environmental residuals for the Geysers (California dry steam)
geothermal electric production are:
- Water
Bicarbonate: 0.06 pounds/million Btu
NO, : 0.02 pounds/million Btu
SO, : 0.02 pounds/million Btu
Solids: 0.13 pounds/million Btu
Organics: 0.03 pounds/million Btu
- Air
C09: 6.66 pounds/million Btu
Ammonia: 0.11 pounds/milion Btu
Methane: 0.42 pounds/million Btu HoS: 0.41 pounds/million Btu
Critical discussion of the technology, its reliability and its
availability
o Geothermal designs are nearly always site specific - technology
is not necessarily transferrable.
Requires a proven resource.
Organic ranking cycle generation is appropriate for low to
moderate temperature geothermal resource use.
Flashed steam depends upon locating a high temperature wet or dry
steam resource. Economy of small-scale flashed steam geothermal
conversion is expected to make flashed steam conversion too
costly for most village applications.
Lower temperature spent fluids may be used for direct heat
applications and are expected to favorably affect economics.
Et2=1
E.2 - HYDROCARBON BASED - ELECTRIC TECHNOLOGIES
E.2.1 - Diesel
E—.2.1.1 - General Description
Thermodynamic and engineering processes involved:
In the diesel engine, air is compressed in a cylinder to a high
pressure. Fuel oil is injected into the compressed air, which is
at a temperature above the fuel ignition point, and the fuel
burns, converting thermal energy to mechanical energy by driving
a piston. Pistons drive a shaft which in turn drives the
generator.
Current and future availability
Diesel engines driving electrical generators are one of the most
efficient simple cycle converters of chemical energy (fuel) to
electrical energy. Although the diesel cycle in theory will burn
any combustible matter, operating life considerations require
that these engines burn only high grade liquid petroleum or gas,
except for multi-thousand horsepower engines which can burn
heated residual oi]. Diesel generating units are usually built
as an integral whole and mounted on skids for installation at
their place of use.
E.2.1.2 - Performance Characteristics
Energy output
Quality - temperature, form
In addition to electricity, diesel generators produce two
sources of capturable waste heat: from the cooling water
and from the exhaust. The cooling water normally is in the
160-200°F range, but it can be 250°F or higher with slight
engine modification.
Quantity
Typically 30 percent of the fuel energy supplied to a
diesel-electric set operating at rated conditions is
converted to electricity. Typical Alaskan diesel
installations range from about 50 to 600 kW, and operate at
much lower average efficiency.
E 2-2
Dynamics - daily, seasonal, annual
Diesel units are preferably base loaded (not subject to dynamic
variations), but in most villages the units are required to
follow changing load conditions.
Reliability
Need for back-up
Typically high reliability of low speed diesels appears
advantageous for rural Alaskan areas. Although most Alaskan
installations are of higher speed ranges (1,800 rpm or
greater), proper installation and maintenance allow
continuous loading. Unit outages are accommodated through
multi-unit installations.
Storage requirements
Fuel tanks located near the power plant may contain up to 24
months supply.
Thermodynamic efficiency
Typically 17-31 percent overall plant efficiency
Net Energy
11,000 - 20,000 Btu/kWh
Bo2 se si=1) Costs
Capital
$300/kW delivered
Assembly and installation
$500/kW
Oper ation
6 percent of investment per year
Maintenance and replacement
2 percent of investment per year for maintenance
8.7 percent of investment for replacement (sinking fund at 3
percent for 10 years)
E 2-3
Economies of scale
Diesel electric unit capacities range from approximately 1 kW to
5 MW; initial cost increases significantly per kilowatt for units
over 1 MW.
E.2.1.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
A 100 kW unit is typically skid-mounted, weighs about 2 tons, is
about 5 feet high, 3-1/2 feet wide, and 9 feet long. The unit
requires a foundation, enclosure, and provision for cooling and
combustion air.
Resource needs
Renewable
N/A
Non-renewable
No. 2 diesel fuel is typically used.
Construction and operating employment by skill
Construction can be done with supervised typical local labor and
equipment. Operation requires an operator/mechanic.
Environmental residuals
The composition of the exhaust is a function of the air-fuel
ratio and the hydrogen-carbon ratio of the fuel. Residuals
include: carbon dioxide, carbon monoxide, hydrogen, and traces
of nitrogen oxides and unburned hydrocarbons.
Health or safety aspects
Fuel tanks require spill protection, often difficult in remote
installations. Potential impacts from such spills include damage
to soil, runoff to water courses, fire hazard.
E.2.1.5 - Summary and Critical Discussion
Cost per kWh is highly site specific with high average load on a
large unit for Alaskan village applications (i.e., 300 kW),
generating cost may be as low as 12¢/kWh.
E 2-4
Resources, requirements, environmental residuals per million Btu or
kWh.
From 0.07 to 0.12 gallons of fuel per kWh.
Environmental residuals per million Btu: N/A.
Critical discussion of the technology, its reliability and its
availability.
Diesel units are typically stocked by several manufacturers and,
as such, have relatively short lead times for use. While this
technology is a widely used bush application, lack of qualified
operators and availability of spare parts have posed problems in
Alaska.
E.2.2 - Gas Turbine
E.2.2.1 - General Description
Thermodynamic and engineering processes involved.
In simple cycle gas turbine plants (see Figure E2.2-1), incoming
air is compressed and heated through combustion with gas or
vaporized liquid fuel injected in a combution chamber. The
heated gas expands through and drives turbines which drive the
electric generator and the inlet air compressor. Fuel is
typically natural gas or very high grade distillate oil.
Current and future availability.
Gas turbine power plants are a proven, established technology,
chiefly used in peaking applications. Base load or cycling
applications generally involve waste heat recovery boilers to
form a combined cycle plant and require availability of low cost
fuel.
E.2.2.2 - Performance Characteristics
Energy output
Quality - temperature, form
Electricity and waste heat at typical temperature of 800°F.
Quantity
I Waste (exhaust) heat amounts to 70 to 85 percent of the Btu
value of fuel input.
HOT EXHAUST AT
LOW PRESSURE
GENERATOR
ADD FUEL IN HIGH ~
PRESSURE COMBUSTION
CHAMBER ”
a
m
FIGURE E2.2-I
E 2-6
Dynamics - daily, seasonal, annual
Typically used for (daily) peaking loads because operating costs
are high relative to fixed costs.
Reliability
Need for back-up
Reliability of petroleum based fuel supply is an issue.
Back-up for peaking applications typically approached using
multiple units, as peaking units often exhibit high
unavailability. Installation lead time is generally short.
Storage requirements
Natural gas is typically provided by pipeline. Distillate oi]
fuels require tank storage.
Thermodynamic efficiency
Simple cycle turbines have typical thermal efficiencies at rate
load of about 28 percent at sea level and 70°F. Efficiency
varies significantly with temperature, elevation, model, and
load.
Net energy
10,500-22,000 Btu/kWh
E2328 = Costs
Capital
$500/kW engine-generator, (800 KW)
Assembly and installation
$1,900/kW
Operation
Large utility units often start, run and stop by remote control.
Alaskan city applications would generally have a part-time
operator; estimate $50,000/yr.
Maintenance and replacement
2 percent of initial investment per year for maintenance
&£ 2-7
3.7 percent of initial investment per year replacement (sinkina
fund at 3 nercent for 29 years)
Economies of scale
Units range in size from 30 kW to over 100 MW. Cost per kilowatt
decreases noticeably up to unit size range of 20 MW.
2.2.4 - Special Requirements and Impacts m Siting - directional aspect, land, height
A typical 800 kw gas turbine weiahs around 17,000 pounas, is 18
feet long by 6 feet wide, and about 6 feet high. The unit comes
with its indoor enclosure, and requires fuel and air supplies an
exhaust connection, and a weather enclosure.
Resource needs
Renewable
N/A
Non-renewable
Natural gas is a near ideal fuel. Liaht distillate oils are
also satisfactory. Blade path corrosion is caused by
sulfur, vanadium, or other metals, and impurities must be
considered when selecting fuels.
Construction and operating employment by skill.
Construction can be performed with supervised local labor and
equipment. An operator/mechanic is required.
Environmental residuals
Oil fired turbines: NO,, SO,, particulates
Gas fired turbines: MQ,
Since gas turbines require clean burning fuels, most stack gas
emissions are nealigible except for NOQ,.
Health or safety aspects
Integration of gas turbine aeneratina units in a community rarely
causes any significant negative health or safety impacts. Most
noticeable impact is enaine noise, whicn can aenerally be
controlled to unobjectionable levels.
nn 2-8
E£.2.2.5 - Summary and Critical Discussion
Cost per million Btu or kwh
A hignly loadea 806 kW machine can be expected to generate power
for 19¢/kWn on oi] fuel costing $1.20/gallon.
Resources, requirements, environmental residuals per million Btu or
kWh.
Need .98 to .17 aallons of turbine fuel per kkh
Environmental residuals per million Btu: N/A
Critical discussion of the technology, its reliability and its
availability.
Gas turbines are a well established technoloay in the U.S.
generating mix. This generation plant type accounts for about
10 percent of U.S. installed capacity and is used primarily to
provide peaking power and reserve generating capacity. Operation
has been proven in much of Alaska, although time required for
maintenance and parts acquisition tend to take longer than in the
lower 48.
In its simplest form, the aas turbine is compact and relatively
light, does not require cooling water, runs unattended, and can
be remotely controlled. In order to be most efficient, however,
gas turbines should be run at or near full load.
E 3-1
£.3 RENEWABLE RESOURCE BASED ELECTRIC SYSTEMS
c &
hydroelectric Generation
.3.1.1 - General Description
Thermodynamic and enaineerinag processes involved:
In a hydroelectric power development, flowing water is directed
into a hydraulic turbine where the eneray in the water is used to
turn a shaft, which in turn drives a generator. Turbines involve
a continuous transformation of the potential and kinetic eneray
of the water into usable mechanical energy at the shaft. Water
stored at rest at an elevation above the level of the turbine
possesses potential energy (head); when flowing, the water
possesses kinetic eneray as a function of its velocity. The
return of the used water to the initial source is performed
through the hydrologic cycle of solar evaporation, rain and
runoff to a body of water for re-evaporation - a direct natural
process using solar energy (Figure £3.1-1). The ability to store
water at a useful elevation makes this energy supply predictable
and dependable.
Current and future availability.
Hydropower presently provides about 10 percent of Alaska's
electric energy needs. Worldwide developments range in size from
over a million kilowatts down to just a few kilowatts of
installed capacity. Hydropower is a time proven method of
aeneration that offers unique advantages. Fuel cost, a major
contributor to thermal plant operating costs, is eliminated.
A major advantaae of hydropower develooments is that they last
much longer than do other plant types. Hydropower developments
are, however, initially costly. Lead time can be as much as 20
years for very large projects, from initial reconnaissance to
commissioning. Licensing procedures for smaller projects, are
being streamlined. Streamlining licensing procedures can
sianificantly reduce the amount of lead time needed to bring a
project on-line.
£.3.1.2 - Performance Characteristics om Oo = > e
ai
ray output
= ity - temperature, form
= 3 z n “N < < a ee a HYDROELECTRIC PLANT
SOLAR ENERGY
EVAPORATION
FIGURE E3 -l
E 3-3
Hydropower provides readily regulated electricity. Water
quality is not affected. A slight temperature differential
may exist between discharge water and the receiving waters.
Quantity
Typical installed capacities in Alaskan power plants range
from 1-20 MW, although larger projects are deing examined.
Dynamics - daily, seasonal, annual
Hydropower plants can be base loaded and/or peak loaded
depending upon site characteristics. In smaller install-
ations, the operating mode may be adjusted seasonally,
depending on the availability of water and the demand for
electricity.
Reliability
Need for back-up
The reliability of the hydroplant itself is very hign.
The transmission lines are often routed through very
rugged terrain and are consequently subject to a variety
of natural hazards. Repairs to damaged lines can
usually be accomplished relatively quicxly. In Alaskan
applications, typical approach is to provide sufficient
installed diesel generation capacity to provide emer-
gency electricity to the utility's customers in the
event that the transmission line or the power plant
should go down. The amount of backup required can be
reduced by building an alternative transmission line.
Storage requirements
Some sites will permit behind the dam storage, allowing use
of the plant to meet variable demand. Reservoirs can range
in size from a few thousand square feet to thousands of acres
for major projects.
Thermodynamic efficiency
Net
For small plants, approximately 80 percent of the energy
stored in the water will result in saleable electricity. The
remaining 20 percent will be lost in the water conduit,
turbine, generator, station service loads, transformers, and
the transmission line.
energy
N/A
m Ww ' > BSc) = COStS
Capital
Capital cost is highly site specific.
For plants below 1 MW in capacity, cost of installation can
easily exceed $20,000 per kW. Installation - cost, therefore,
depends on both site conditions and cost of alternative
generating methods. (The plant will not be built if other
methods are available at lower life cycle cost.)
Assembly and installation
(included above)
Operation and maintenance
Operation and maintenance costs for a hydroelectric development
normally depend on the size of the installation and the method of
operation. Most larae installations will be attended full-time wnile many of the smaller installations are operated remotely and
visited only occasionally for maintenance. Tynical annual
operation and maintenance cost for large installations is
$.001/kWh produced plus $5/kW of installed capacity. For small
plants, costs may increase to as high as $.10/kWh and $10/kW.
Economies of scale
See above.
ec E£.3.1.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
A suitable site for any hydropower development must, of course,
be found. Requirements include an adequate water supply and a
reasonable proximity to the load center (consumers). Site
preparation for a hydropower development may involve modification
of the existing terrain with resulting changes in both the
topography and in the natural or existing drainage pattern.
Small run-of-the-river installations may require minimal dam
construction or disturbance of the area. The project boundary
(the outer limits of the land directly affected by the project)
may encompass several hundred acres. The impacts of a hydropower
development primarily fall within the areas of land use and
stream ecology, with severity depending on the site. A special
advantage of a hydropower development is that it is effectively
non-polluting.
E 3-5
Resource needs
Renewable
Rainfall and catchment
Non-renewable
N/A
Construction and operating employment by skill
Construction of a hydropower development requires the employment
of hiahly skilled individuals experienced with equipment
installation and startup, typical construction trades and
laborers who usally come from the local workforce. Operators of
hydroplants are often drawn from the local population and given
training to qualify them for the position.
Environmental residuals
None
Health of safety aspects
Public safety, legal liabilities, insurance, and land use issues
must be addressed prior to construction of a hydropower
development.
£.3.1.5 - Summary and Critical Discussion
Cost per million Btu or kWh
Site specific
Resources, requirements, environmental residuals per million Btu or
kWh.
Site specific
Critical discussion of the technology, its reliability and its
availability.
Hydroelectric power generation is a well established technology.
Although each project, and many of its components, are generally
"custom" design jobs (particularly with large projects),
significant progress nas been made towards producing standardized
components for small scale plants. With recent simplifications
E 3-6
of the licensing procedures, small plants (i.e., 500 kW) can now
be designed and operating within a few years.
Hydroplants can be remotely operated from a central station. At
large scale plants, an operator is usually stationed at the plant
to take care of routine maintenance. Small scale plants suitable
for supplying power to a village would normally run unattended.
Safety of large hydropower developments has long been a concern
of the Federal and State governments. Criteria for safe design
and operation of hydropower developments are well etablished and
major failures are very rare. The hydraulic turbine, and its
component parts, are designed and are built to exacting
specifications and is extremely reliable; the turbine often has a
useful life of upwards of 50 years.
£.3.2 - Wind Energy Conversion Systems
E.3.2.1 - General Description
Thermodynamic and engineering processes involved
The thermodynamic process involved stems from the sun, the
primary energy source which produces the wind. Wind energy
cannot be stored, is intermittent, generally unpredictable and
thereby undependable as a source of firm energy. Most wind
generators rely on wind flow over an air foil assembly to create
differential pressures along the air foil. This differential
pressure results in rotation of the assembly around a fixed axis
(drive shaft) to which it is attached. Power from the wind is
transmitted through the drive shaft and accompanying gear box to
an electric generator. (See Figure £3.2-1).
Three types of generators are presently in use with wind energy
systems. These are the DC generator, the AC induction generator
and the AC synchronous generator. Of the three types the AC
induction generator is the most widely used: an induction
generator is not a stand-alone generator and must be connected to
an external power system of relatively constant frequency and
voltage to operate properly.
Current and future availability
Estimation of availability of wind at useful velocities require
long-term records to estimate the potential energy. Lesser
records provide less credible estimates.
Availability of small size units in the 1.5 kW to 20 kW range is
good. Large units (100 kW and above) are currently being
demonstrated in both the government and private sectors and are
GEARTRAIN AND GENERATOR HOUSING \ 74 ALT i WIND
(Any Direction) wee IN X A. 7 \ A NZ (AZ LINZ NX HORIZONTAL AXIS WIND TURBINE GENERATOR VERTICAL AXIS WIND TURBINE GENERATOR
WIND TURBINE GENERATORS
FIGURE E3. -I
E 3-8
commercially available in sizes of 200 MW scale. Demonstrations
of multi-megawatt sizes are in process.
E.3.2.2 - Performance Characteristics
Energy output
Quality - temperature, form
Electricity
Quantity
Wind generator output generally varies as a function of the wind velocity to the third power (V3), beginning at a cut-in wind velocity (normally about 8 mph) up to a cutoff
wind velocity, i.e., a machine rated at 200 kW in a 27 mph
wind can be expected to produce the following in lighter
winds:
7 mph: machine will not operate
12 mph: 17 kW
18 mph: 59 kW
24 mph: 140 kW
30-36 mph: typical cut out speed
Actual performance will vary from one design to the next.
Reliability
Need for back-up
In general, except for the small single dwelling
wind/battery systems, wind power generation is not a stand
alone system. Diesel or another form of back-up generation
must be provided for days that the wind does not blow with
sufficient velocity to produce adequate energy from the
WECS. Additionally, normal operating mode would be in
parallel with an on line diesel. The diesel would generate
the bulk of demanded power output and adjust its load
according to the instantaneous output of the wind
generator.
Storage requirements
Batteries can be used for storage, at considerable expense. The
most cost effective way to use wind power on a utility grid
appears to be through direct displacement of fuel otherwise
required for diesel generation without attempting to store the wind energy (as described above).
E 3-9
Thermodynamic efficiency
Actual conversion efficiency of wind turbine is generally on the
order of 40 percent of available wind energy.
Net energy
N/A
E.3.2.3 - Costs
Capital
Machine size Type Cost $/kW
200 kW horiz axis $520,000 (FOB) $2,600
50 kw vertical axis $140,000 (FOB) $2,800
10 kW horiz axis $ 17,000 $1,700
Assembly and installation
One example of a 200 kW horizontal axis mchine has been
constructed in a remote area without use of a crane. The machine
was constructed (using a gin pole and electric hoist) piece by
piece from the ground up. This is considerably more expensive
than a crane (when available), but will probably be required for
most Alaskan villages. Installation costs in rural Alaskan
villages are estimated to be roughly $2,600/kW for all classes of
machine sizes. This may vary somewhat in those villages where
there exist conditions which significantly expedite or complicate
installation work. Delivered and erected cost is estimated to be
roughly double the cost of the basic equipment.
Operation and Maintenance
Barring major equipment failures, annual operating costs for
horizontal axis machines in the 200 kW class are expected to be
limited to occasional adjustment and inspection, with periodic
preventive maintenance.
E 3-10
Estimated
Operation &
Unit Size Maintenance Replacement Total/Yr.
200 kW (hor) $7,500 Est $15,000 $22,500
Economies of scale
Economies of scale generally favor installation of large centralized
wind generators over the small individually owned wind generators.
This is less the function of wind turbine cost than of system opera-
ting limitations and their effect on total system cost. Unit sizes
are, of course, restricted by village power requirements. Because of
electrical system stability limitations, the total installed WECS
instantaneous output should not exceed 25 percent of the total system
load.
Siting - directional aspect, land, heioht
Siting requires the selection of a location with average annual wind
soeeds approaching or exceeding 10 mph. Heiaht of the mounting tower
will vary depending on location and machine size and type. A 200 kW
horizontal axis unit can be expected to be 150 feet high from blade
tip to ground, with a 90 foot tower.
Resource needs
Renewable
Average annual wind speed in excess of 10 mph (typical).
Although some machines may operate in lighter winds, output
will be minimal.
Non-renewable
N/A
Construction and operating employment by skill
Certain aspects of construction (i.e., foundation, tower
installation) could be performed by unskilled labor under close
supervision. An operator would not be required for horizontal
axis turbine, as these are operated unattended. Vertical axis
designs (Darrieus) require a start-up system and, therefore, a
part-time operator.
Environmental residuals
Aside from visual impact, little environmental impact is
Ea3-S
E 3-11
anticipated when operating only a few machines within a small
geographic area. Electromagnetic communications interference and
very low frequency sound generation have been problems with
recent units.
Health or safety aspects
Public safety, legal liabilities, insurance and land use issues
must be addressed prior to installation of a utility owned or
operated WECS. Primary concerns are blade failure and tower or
foundation failure in high winds.
E.3.2.5 - Summary and Critical Discussion
Cost per million Btu or kWh
Site specific
Resources, requirements, environmental residuals per million Btu or
kWh
N/A
Critical discussion of the technology, its reliability and its
availability.
Wind power suffers from one obvious disadvantage; the
intermittent and fluctuating nature of wind. A small utility must install sufficient primary generation at additional costs to
meet demands on those days when the wind does not blow with
sufficient velocity to produce a significant output from the
WECS.
Besides the fickleness of local wind conditions, technical,
environmental, and social problems must be addressed. Technical
and social barriers that must be dealt with include power system
stability; voltage transients, harmonics; fault-interruption
capability; effects on communications and TV transmissions,
public safety; legal liabilities and insurance, and land use
issues.
- Photovoltaic Cells
£.3.3.1 - General Description
Solar cells are electric eneray generators that consume no fuel, make
no noise, pose no health or environmental hazards and produce no
waste products. These cells convert light directly into electricity
E 3-12
via light sensitive semiconductors. Since no moving parts, no high
pressures and no high temperatures (excluded focused collector
designs) are involved, this would be an ideal way of generating
electricity.
E.3.3.2 - Performance Characteristics
Efficiency of conversion to electricity is about 12 percent.
E.3.350 — Costs
Today, solar-cell power is too expensive to compete with fossil-fuel power for all but the smallest applications in unattended service
where cost of power is of little concern. The single crystal silicon
solar cell has a laboratory or rated efficiency of about 12 percent
and costs $10.00 per peak watt or $10,000 per peak kilowatt.
In-field panel efficiency is generally lower than rated efficiency
for cell arrays, due to cell and panel mismatches, elevated operating
temperature and wiring and conversion losses.
These cells must be mounted in a cell array panel, with a support and aiming structure. In addition to the cell array, storage equipment
(batteries) and inverters will be required if a "stand alone system" is desired to supply the equipment and devices presently in use with electric energy. Energy storage helps satisfy demand during periods
of little or no sunshine, as well a supplying peak power. Presently
available storage devices are lead-acid batteries, which are
expensive. The life of a lead-acid battery is limited to a few
years with daily cycling, even with a charge controller.
Costs for a complete stand alone system rated at a peak output of
5kW, based upon appropriate storage for a lower 48 state application
were estimated by a major manufacturer as $20 per peak watt, or
$100,000. The application of such a system at an Alaskan site was
seen as likely to require a significant increase in battery capacity
as latitude approached the Arctic circle and increasingly limited
usefulness in winter regardless of battery capacity. Cost breakdown
provided for the lower 48 system is as follows (on an approximate
basis):
Cell arrays $10/watt
Array support,
structure, controls $ 3/watt
Batteries $ 5/watt
Inverter $ 2/watt
$20/7watt
E 3-13
Breakthroughs in cell cost are anticipated, but will likely be offset
for stand-alone residental Alaskan applications by battery
requirements. Thus the manufacturer saw little potential for the
Alaskan market.
E.3.3.4 - Summary and Critical Discussions
The costs of both photovoltaic cells and low-maintenance storage
mediums must be reduced before they can economically compete with
conventional generation of electric energy. At $20 per peak watt,
annual replacement allowance with a 20-year life is $6,700 for a5 kW
system using the 3 percent cost of money rate assumption. This is
equivalent to 76.4 cents per kilowatt hour if the system were to
Produce an average of 1 kWh for every hour of the year. Any repair
or cleaning costs are additional. A backup generating system or
extensive battery storage will be required for extended periods of
darkness and/or cold weather, adding to initial cost beyond the $20
per peak watt figure. Batteries will also need replacement every
five to ten years if properly maintained.
E 4-1
E.4 HEATING TECHNOLOGIES
£.4.1 - Diesel Waste Heat Recovery
E.4.1.1 - General Description
Thermodynamic and engineering processes involved
The present use of fossil fuels (coal, gas, oil) to produce more
useful forms of energy (heat, electricity, motive power) is less
than 100 percent efficient. For example, if a machine burns a
certain quantity of fossil fuel and produces useful output (shaft
horsepower, electrical energy, steam, hot water or air for space
heating) equivalent to 30 percent of the fuel burned, the energy
represented by the remaining 70 percent of the fuel will appear
as unused or "waste" heat. Such heat most often appears as hot
exhaust gas, tepid to warm water (65°F-180°F), hot air from
cooling radiators, or direct radiation from the furnace, steam
power plant, diesel engine, etc.
Diesel waste heat can be recovered from engine cooling water and exhaust (as shown in Figure £4.1.1), or either source separately.
The waste heat is typically transferred to a water-qlycol
circulating system in Alaskan applications. The heated
circulating fluid can be used for space, water, or process heating.
Current and future availability
Recovery of diesel waste heat in Alaska is growing as a result of
sharp increases in diesel fuel costs.
Recovery of jacket water heat only is most common in Alaska and is shown in Figure £4.1.2.
Diesel waste heat availability is directly related to the
location and operating cycles of the engine installation.
E.4.1.2 - Performance Characteristics
Energy output
Quality - temperature, form
Cooling water is typically 160-200°F. Exhaust heat varies
with engine speed and load and ranges from about 300-600°F.
TO REMOTE FROM REMOTE HEAT LOOP HEAT LOOP
EXHAUST GAS co m= (ols SILENCER
CHECK VALVE
ENGINE THERMOSTAT
ENGINE - BOOSTER THERMOSTATIC
PUMP CONTACTOR
JACKET WATER & EXHAUST WASTE HEAT RECOVERY SYSTEM
FIGURE E4.!-!
SPACE HEAT
THERMOSTATIC
THERMOSTATIC VALVE
2 ENGINE |
(v) Sg age | SW | aaemee eee, THERMOSTATIC — SWITCH
JACKET WATER WASTE HEAT RECOVERY SYSTEM
FIGURE E4.!-2
E 4-4
Quantity
Diesel engines generally convert about 30 percent of the fuel
input to shaft power which can be converted to electricity, 30
percent as cooling water heat, 30 percent as exhaust heat, and
10 percent as radiation loss. All of the cooling water heat,
about half of the exhaust heat, and all of the radiation can be
usefully captured if space heat needs are in economic proximity.
AVERAGE ANNUAL HEAT LOAD FOR VARIOUS COMMUNITIES
Average Average Annual! Degree Temperature Heat Load
Location _Days | (°F) (Btu X 10°)
Anchorage 10,814 35.24 147.9
Barrow 20,174 9.73 256.4
Bethel 13,196 28.85 175.10
Cordova 9,764 38.25 135.1
Fairbanks 14,279 25.88 187.7
Juneau 9,075 40.14 127.0
King Salmon 11,343 33.92 153.5
Kotzebue 16,105 20.88 209.0
Nome 14,171 26.18 186.4
1 Based on a "standard" 10,000 t3 building, 35' X 35' X 8'. Walls of
2" X 4" construction on 16" centers, with R-11 insulation, U factor .07.
Roof and floors 2" X 8" or 2" X 12" on 16" centers, unheated attic, 6
inches of insulation, U factor .07. Two 24" X 40" windows, 1 1/2 air
changes per hour.
E 4-5
Table E4.1.1 indicates the annual recoverable waste heat for
various diesel unit sizes and generating efficiencies (i.e.,
kWh/gal and heat rates in Btu/kWh) and assumes that one-third of
the fuel heat is recoverable.
TABLE £.4.1.1
WASTE HEAT AVAILABILITY2/
106 Btu/year Available at Indicated Generating Efficiency
12 kWh/gal 10 kWh/gal 8 kWh/gal kW kWh/year (11,500 Btu/kWh) (13,800 Btu/kWh) (17,250 Btu/kWh)
50 175,200 671.6 805.9 1,007.4 75 262,800 1,007.4 1,208.9 1,511.1 100 350,400 1,343.2 1,611.8 2,014.8 200 700,800 2,686.4 3,223.6 4,029.6
1/ Assumes 138,000 Btu/gal fuel, 0.40 load factor.
Dynamics - daily seasonal, annual
Waste heat is available whenever the electrical generation source
it is dependent upon is in operation.
Reliability
Need for back-up
Heat recovery systems require a back-up heat source in case
of system shutown. This is typically provided by boilers
and heaters that existed prior to installation of the
recovery system and were consequently idled by it.
Storage requirements
Waste heat is generally utilized as it is recovered: storage of
heat is atypical.
Thermodynamic efficiency
Net
N/A
energy
N/A
E 4-6
E.4.1.3 - Costs
Capital
Waste heat utilization is not free, even though there may not
actually be a direct charge for the heat. The equipment for
utilizing this heat requires a sizeable capital investment and is
feasible only when the cost for associated equipment is less than
the cost of the fuel saved.
The cost of heat exhanaers, waste heat boilers and associated
equipment depends on the generator installed at the location.
These costs can be determined by contacting the qenerator's
manufacturer and obtaining the price of the specific models of
waste heat recovery equipment specifically designed for that
generator. Using some typical prices as a guideline, we can
estimate that the component price for a heat recovery silencer
will range from $4,600 for a 55 kW engine-generator set to
$20,000 for an 850 kW engine-generator. These units would allow
capture of waste heat equivalent to approximately one-sixth of
the fuel supplied to the engine-aenerator. To these prices must
be added the cost of installation and auxiliary equipment with a
potentially major investment required in distribution systems.
A heat exchanger for the jacket water system will range from
perhaps $1,200 for a 55 kW engine-aenerator set to perhaps $5,000 for the 950 kW engine-generator set. These theoretically can
capture waste heat equivalent to approximately one-third the fuel
supplied to the engine-generator.
Overall cost is site specific: a complete system recently
installed in Galena to provide heat to 3 buildings from 3 diesel generators cost $325,000 installed (1981). Estimated system
capability based upon available data is 2 million Btu/hr,
resulting in a cost per therm of some $16,000.
Operation
N/A
Maintenance and replacement
2 percent of capital investment per year for maintenance
3.7 percent of investment per year for replacement (sinking fund
using 3 percent for 20 years)
E 4-7
Economies of scale
Small systems may be as beneficial economically as very large
systems because required equipment is less sophisticated and
consequently less costly. Cost of redundant system is typically
lower (per unit recovered) in smaller systems, also.
E.4.1.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
Should be immediately adjacent to diesel engine (or other heat
source).
Resource needs
Renewable
N/A
Non-renewable
Waste heat recovery uses an otherwise lost resource
Construction and operating employment by skill
Jacket water heat recovery systems can be installed and operated
by local personnel qualified for similar work with diesel
generators.
Environmental residuals
Environmental residuals are only those associated with the means
of electical generation employed, the reduction of waste heat
release is a net benefit.
Health or safety aspects
No negative health or safety aspects except those previously
associated with the heat source.
£.4.1.5 - Summary and Critical Discussion
Cost per million Btu or kWh
Site specific
E 4-8
Resources, requirements, environmental residuals per million Btu or
kWh.
These items are a function of the heat source.
Critical discussion of the technology, its reliability and its
availability.
Waste heat capture, while not a fuel for generation, can provide
savings in overall fuel use.
Engine cooling water can be used in two ways: 1) the hot coolant
from the engine or industrial process can be piped directly to
radiators in the space to be heated, or to other processes which
can use the heat; or 2) the hot coolant can, via heat exhanger,
heat a medium, probably water, which will be used for space
heating or other processes.
Most engine manufacturers advise against the first approach. A
leaking radiator can destroy the engine, whereas in the second
system the engine will be less affected. Engine water must be
soft and free of impurities that could reduce the heat transfer
in the engine. This can be controlled in a small system using
the same water over and over, but is much more difficult in a
system where engine water is circulated through the heating
system. The second approach involves lower effectiveness of heat
recovery, but is the most common method employed when utilizing
the waste heat from the engine cooling water.
The critical point of any effort to evaluate waste heat recovery
is that point at which the equivalent annual cost of recovering
heat will be less than the cost of generating heat by other
means. Low grade waste heat cannot be transported very far for
its actual resale value.
£.4.2 - Electric Heating
£.4.2.1 - General Description
Thermodynamic and engineering processes involved
Electricity is passed through resistance wiring thereby
generating heat. The heat is transferred to air or water.
Current and future availability
Electric heat is clean, noiseless, easily controllable and
relatively efficient. Electric heat is a recognized means of
heating buildings where heat losses are held to a low level and
the cost of electricity is not prohibitive.
E 4-9
E£.4.2.2 - Performance Characteristics
Energy output
Quality - temperature, form
Heat or hot water for space heating applications
Quantity
3,412 Btu out per kWh in.
Dynamics - daily, seasonal, annual
Available whenever there is electricty.
Reliability
Need for back-up
Typically, none with a highly reliable electric supply
system.
Storage requirements
None
Thermodynamic efficiency
So far as the conversion of electric energy into heat is
concerned, all types of electric resistance heaters are equally
efficient. They all produce 3,412 Btu per kilowatt-hour of
electrical energy used. From a thermodynamic efficiency
standpoint, electric heaters are 100 percent efficient at the
place of use.
E.4.2.3 - Costs
Capital
Approximately $2,000 for a central home system (installed).
Operation
A function of the cost of electricity
Maintenance and replacement
Virtually maintenance free; replacement life estimated to be 20
years.
E 4-10
Economies of scale
Not appropriate.
E.4.2.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
In typical residential installations, a metal casing, in the same
configuration as conventional baseboard along walls, contains one
or more heating elements placed horizontally. The vertical
dimension is usually less than 9 inches, and projection from wall surface is less than 3.5 inches. Units are available from 1 to
12 feet long with ratings from 100 to 400 watts per foot of length and are designed to be fitted together to make up any
desired continuous length or rating.
Resource needs
Renewable
N/A
Non-renewable
Electricity
Construction and operating employment by skill
Simple to install and effectively automatic
Environmental residuals
None
Health or safety aspects
None with proper installation.
E.4.2.5 - Summary and Critical Discussion
Cost per million Btu or kWh
Cost is a function of the cost of electricity
The most economical electric heating systems from an operating
standpoint are of a decentralized type, with a thermostat
provided on each unit or for each room. This permits each room
£.4.3
E 4-11
to compensate for heat contributed by sources auxiliary such as
sunshine, lighting, and appliances. This arrangement also gives
a better diversity of the power demand due to noncoincidence of
electric load from all units of an installation. Manual switches
are often provided to permit cutting off heat or reducing
temperature in rooms when not in use.
Resources, requirements, environmental residuals per million Btu or
kWh.
A function of the resource used to generate electricity. See eC appropriate Appendix C profiles.
Critical discussion of the technology, its reliability and its
availability.
In summary, a simple list of some of the benefits and advantages
of electric heat includes the following:
Dependable
No fuel deliveries
No fuel storage problems
Clean
No venting required
No oxygen consumption
Individual room-by-room control
Quiet
Easy to install
Space-saving
"Flameless"
- Passive Solar Heating
E.4.3.1 - General Description
Passive solar heating makes use of solar energy (sunlight) through
energy efficient design (i.e., south facing windows, shutters, added
insulation) but without the aid of any mechanical or electrical
inputs. Space heating is the most common application of passive
solar heating. Because such solar heating is available only when the
sun shines, its availability is intermittent (day-night cycles) and
variable (winter-summer cloudy-clear).
£.4.3.2 - Performance Characteristics
The central Alaska area is located roughly between 61° and 66° North
latitudes. The possible insolations shown on Table £4.3.1 for Bethel
and Fairbanks are considered to approximate conditions within this
TABLE 4.3.1
CENTRAL ALASKA - SOLAR ENERGY
Average insolation/sq fc / ; : 2
a Vertical South Facing Surface 200 Sq Ft South Facing Windows Heating Degree” Days 600 sq.ft. Residence
Fairbanks(64°49'N) Bethel(60°47') ‘Fairbanks Bethel Fairbanks Bethel Fairbanks Bethel
JAN 864 832 172.8 X 10° 166.4 X 10° 2,384 1,857. 412.6 X 10° 321.4 x 10°
FEB 1,149 1,224 229.8 X 163 244.8 x 203 1,890 1,590 370.9 X 10° 311.6 x 10°
MAR 1,808 1,892 361.6 X 10° 278.4 x 10° 1,721 1,662 283.0 X 10° 251.7 x 10%
APR 1,679 1,689 335.8 X 10° 337.8 x 10° 1,083 1,215 185.8 X 10° 108.5 x 10°
MAY 1,323 1,176 254.6 X 10° 235.2 x 103 549 772 90.3 X 10° 127.0 x 10°
JUN 1,271 1,021 254.2 X10? 204.2 x 102 211 492 40.1 xX 102 76.5 x 10°
JUL 1,158 886 231.6 X 102 177.2 x 102 148 319 23.8 x 107 = 51.4 x 102
AUG 1,094 715 218.8 X 10? 143.0 x 10° 304 394 44.1 x 102 57.2 x 102
SEP 912 874 182.4 xX 10° 174.8 x 10° 618 600 115.1 x 10° 111.8 x 10%
oct 723 823 114.6 X 102 164.6 X 10° 1,234 1,079 197.8 X 10° 173.0 x 10%
NOV 513 518 102.6 X 10° 103.6 x 10° 1,866 1,434 327.0 X 109 ~— 251.3 xX 10° DEC 263 502 52.6 X 10° 100.4 x 10° 2,337 1,879 395.7 X 10° 318.1 x 109
ANNUAL 388.9 X 10° 368.9 X 10° 77.8X 10° 73.8 x 10° 14345 13203 75.2 x 10° 69.2 x 10°
1 "Solar Energy Resource Potential in Alaska" by J.P. Zarling, R.D. Seifort for U of A Institute of Water Resources, 1978.
2 “Monthly Normals of Temperature, Precipitation and Heating and Cooling Degree Days 1940-70 for Alaska," U.S. Department of
Commerce National Oceanic and Atmospheric Administration Environmental Data Service. el-b 4
£.4.4
E 4-13
area. The Bethel and Fairbanks data has been developed with the
F-chart computer program and takes climate and typical weather
conditions into account. The annual amount of solar energy available
can satisfy all heating needs of an average home if enough collecting
surface area and adequate storage could be installed. Heat storage
or supplement heating by other means would be necessary for about 6
months of the year when the available insolation cannot satisfy the
heating needs. If passive solar heating is considered, where the
solar energy is sufficient and with energy efficient design
(increased insulation, south facing windows with shutters, etc.) it
is conceivable that even in the months of November, December and
January approximately 20-40 percent of the required heat can be
supplied by the sun if 200 square feet of south facing windows can
collect energy for an average size (600 sq.ft.) residence found in
the Alaskan bush.
£.4.3.3 - Costs
The integration of passive solar heating into the design and
construction of a new residence adds little to the overall structure
cost. Typical increases in structure costs range for 0 to 5 percent.
In general, it is not economical to extensively remodel existing
residences to take advantage of passive solar heating.
- Coal Fired Furnace
E.4.4.1 - General Description
Thermodynamic and engineering processes involved.
Coal is manually or automatically fed to a controlled combustion
chamber equipped with heat exchange surfaces and an exchange fluid circulating system. Designs are available for either
forced hot air or hydronic (hot water) systems.
Current and future availability
Units are commercially available.
E.4.4.2 - Performance Characteristics
Energy output
Quality, temperature, form
Heat
E 4-14
Quantity
Unit sized range upwards from approximately 100,000 Btu/hr
for "high technology" units; combination wood/coal stoves
are also available.
Dynamics
N/A
Reliability
Need for backup
A portable oi] heater might be kept as a standby
Storage Requirements
Adequate coal in storage for full heating season (including
reserve) in moisture protected bin.
Thermodynamic efficiency
50 to 70 percent for "high technology" units; 30 to 70 percent
for stoves.
Net Energy
N/A
E.4.4.(3:--) Costs
Capital
Investment can range up to $30,000 per million Btu/hr for fully
automated home sized hot air system.
Commercial building sized systems approach $40,000 per million
Btu/hr.
Installation
Transport and installation expected to equal equipment cost.
Operation; maintenance and replacement
Depends upon system and coal used. Maintenance not expected to
exceed $500 per year of use. Replacement sinking fund payment
per year (at 3 percent for 20 years) is 3.7 percent of initial
installed cost.
£.4.5
E 4-15
Economy of Scale
N/A
E.4.4.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
Building heating system must be compatible; building layout must
accommodate size of unit and access requirements to coal bin
location. Ash disposal area required.
Resource needs
Renewable
N/A
Non-renewable
Coal must be available in adequate quantities
Construction and Operating Employment by skill
Factory representative might provide direction to local labor for
the more elaborate designs.
Environmental Residuals
Solids: stack particulate, ash for diposal
Health or Safety aspects
Normal care required around heated surfaces.
- Wood Fired Furnace
E.4.5.1 - General Description
Thermodynamic and engineerng processes involved
Wood is manually fed to a combustion chamber designed for
radiant/convective heating, radiant forced convective heating or hydronic heating.
Current and future availability
Commercially available and widely in use.
E 4-16
E.4.5.2 - Performance Characteristics
Energy Output
Quality, temperature, form
Heat
Quantity
Usable stove outputs range from 10,000 Btu/hr and up.
Dynamics
Depend upon operator
Reliability
Need for backup
Generally reliable with reasonable attentiveness to fire and
stack cleaning. Portable oi] heats might be kept as
standby. Subject to wood availability.
Storage Requirements
Wood storage requirements are site specific
Thermodynamic Efficiency
Perhaps 20 percent for some homemade designs up to nearly 80 percent for some airtight designs.
Net Energy
N/A
E.4.4.5 - Costs
Capital
Minimal for homemade stoves, can approach $20,000/million Btu/hr
for some airtight designs on market.
Installation
From negligible to equal to equipment cost
E 4-17
Operation, Maintenance and Replacement
Widely variable maintenance needs with operating practices, unit
design and wood used; replacement sinking fund payments (at 3
percent for 15 years) are 5.4 percent of initial cost per year.
Economy of Scale
N/A
E.4.4.6 - Special Requirements and Impacts
Siting - directional aspect, land, height
Building design must accommodate stove type selected.
Resource needs
Renewab 1e/Non-renewable
Wood requirements will be site specific based upon heating value,
desired heat level, stove operating practices. Wood supply may
be effectively non-renewable with overcutting of a slowly growing
tree stock.
Construction and Operating Employment by skill
No special skills generally required unless high efficiency
masonry designs are to be installed.
Environmental Residuals
Solids: particulates, ash for disposal
Land: tree cutting and transport impacts.
Health or Safety Impacts
Primary impacts are safety hazards of cutting and splitting wood;
normal care around heated surfaces.
ENS:
£.5 - FUEL CONVERSION TECHNOLOGIES
E.5.1 - Coal Gasification
£.5.1.1 - General Description
Thermodynamic and engineering processes involved
Low or medium Btu gas (100-300 Btu/scf) can be manufactured from
coal in commercially available equipment. However, the use of
this gas for power generation is a very complex process, as depicted in Figure £5.1-1.
Current and future availability
The prospect of coal gasification contributing to Alaska power in
the next 10 years is remote for other than demonstration type
plants. Existing commercial facilities and development projects
are far too large in scale for village applications.
£.5.1.2 - Performance Characteristics
Energy output
Quality - temperature, form
Gas of 100-300 Btu/scf
Quantity
Depends on quantity of feedstock available and desired
output. Process equipment is generally custom built.
Dynamics - daily seasonal, annual
Gasifiers are best operated on a continuous basis.
Reliability
Need for back-up
Fossil power systems displaced by gasification would
typically be used for back-up.
Storage requirements
Like coal-fired steam plants, a 3-month fuel supply is typical.
Extreme climates may require up to 9 months worth of coal in
storage.
E 5-2
(5) GENERATOR
C\- —-— — —air
EXHAUST \__/ TURBINE He SiGdS
v Gi
SATURATOR
secceetlllp
Sami)
as OIL
COAL
FEEDWATER
CLEAN FUEL GAS FROM COAL FOR POWER GENERATION
FIGURE E5.1-1
E 5-3
Thermodynamic efficiency
65 percent to 85 percent conversion of fuel feedstock to usable
energy form.
Net energy
N/A
ECO LoS iCOStS
Capital
N/A
Assembly and installation
N/A
Operation
N/A
Maintenance and replacement
N/A
Economies of scale
"Small" commercial units produce about 2 billion Btu per day.
E.5.1.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
As for coal-steam plants, fuel storage is the major land
requirement. Gasification at the mine can cut storage
requirements to 30 days.
A representative 1,000 kW gasifier is reported to be about 60
feet high and 8-10 feet in diameter.
Resource needs
Renewable
N/A
Non-renewable
Coal of virtually any quality can be utilized.
Construction and operating employment by skill
Hiahly skilled construction and operating personnel are
required.
E 5-4
Environmental residuals
Solids: ash, sulfur
Air: SO, and particulates
Health or safety aspects
The low Btu gas is highly flammable and generally contains high
levels of toxic carbon monoxide.
£.5.1.5 - Summary and Critical Discussion
Cost per million Btu or kWh
Lower 48 costs of a "small" commercial unit is $3.00 per million
Btu per a manufacturer's estimate for 5 billion Btu per day.
This cost may increase by a factor of 2-3 for Alaska.
Resources, requirements, environmental residuals per million Btu or
kWh
Need 1.2 Btu in fuel (or more) for each Btu of aas generated.
Environmental residual figures are based on an ash agglomeratina
fluidized bed low-Btu gasification process:
Sulfur: 2.77 pounds/million Btu
NO, : 0.02 pounds/million Btu SO, : 0.04 pounds/million Btu
Particulates: 0.14 pounds/million Btu
CO; 0.01 pounds/million Btu
Solids: Ig pounds/million Btu
Critical discussion of the technology, its reliability and its
availability.
While coal could be gasified in a so-called synthetic fuel plant,
the state of the art and associated economics make it appear
doubtful that a fuel facility would be constructed solely for the
purpose of providing fuel for limited electrical generation.
Suitable low-Btu gasifiers are air blown units of the fixed bed
type operating at atmospheric pressures. These units are
"small": daily production is less than 2 billion Btu of hot, raw
gas. Low-Btu gas is economically attractive only if produced
near its usage - nominally within a half mile. The cost of the
gas in the lower 48 is expected to range up to $5.00 per million
Btu. Actual cost as a specific location is influenced by the
price of coal (about half the production cost), the load factor,
the gas cleanup requirements for specific process use, and clean
air requirements.
E 5-5
E.5.2 - Wood Gasification
E.5.2.1 - General Description
Thermodynamic and engineering processes involved
Low Btu gas (100-300 Btu/scf) has been manufactured from wood in
equipment under development in Alaska. Gas is produced through
partial combustion at high temperature in an oxygen starved
atmosphere.
Current and future availability
The prospect of wood gasification contributing to Alaska power in
the next 10 years is remote for other than demonstration type
plants. Very few commercial facilities operating in conditions
equivalent to village applications are known to exist.
E.5.2.2 - Performance Characteristics
Energy output
Quality - temperature, form
Gas of 100-300 Btu/scf
Quantity
Depends on quantity of feedstock available and desired
output. Process equipment is generally custom built.
Dynamics - daily, seasonal, annual
Gasifiers are best operated on a continuous basis.
Reliability
Need for back-up
Fossil power systems displaced by aasification would tyically
be used for back-up.
Storage requirements
Application in the extreme climates common to Alaskan villaaes
may require up to 9 months worth of wood storage.
Thermodynamic efficiency
65 percent to 85 percent conversion of fuel feedstock to usable
eneray form.
E 5-6
Net energy
N/A
5.2.3 - Costs
Capital
N/A
Assembly and installation
N/A
Operation
N/A
Maintenance and replacement
N/A
Economy of scale
Will be limited by proximity and difficulty in harvesting of
forest reserves.
E.5.2.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
Gasifier will need to be close to wood source to reduce cost of
transport.
Resource needs
Renewable
Wood as well as other cellulosic biomass can be utilized.
Other biomass includes: straw, almond shells, and peach pits,
for example.
Non-renewable
N/A
Construction and operating employment by skill
Skilled construction and operating personnel are required.
E5523)
E 5-7
Environmental residuals
Solids: ash, tars
Health or safety aspects
Low Btu gas is flammable and generally contains high levels of
toxic carbon monoxide.
5.2.5.- Summary and Critical Discussion
Wood gasification is presently under development for application to
Alaskan village diesel generators in an AVEC administered program.
Anticipated program progress indicates a possible infield
demonstration no earlier than 1986, with commercial service
introduction perhaps by 1988.
At present, success of the development program is not certain, thus
availability of wood gasifiers for diesel electric application is
uncertain.
Existing gasifier designs as applied to provide heating fuel would
appear to offer no benefit over direct wood fired heating.
- Biogas Generation
E.5.3.1 - General Description
Biogas (two-thirds methane and about 600-700 Btu/scf) can be produced
from organic waste. In a biogas generation system, heat is used to
promote anaerobic bacterial digestion. Figure £5.3.1 depicts the
biogas generation process.
Anaerobic fermentation of organic products results in methane, carbon
dioxide, hydrogen, traces of other gases, and the production of some
heat. The residue remaining is hygienic, rich in nutrients, and high
in nitrogen. Potentially harmful organisms are killed by the absence
of oxygen during the fermentation process.
There are over 50,000 small scale biogas producers in rural India and
over half a million reported in mainland China. A demonstration unit
in Alaska works on crab processing wastes. The technology is quite
well established.
Units range from "one cow" size (20,000-30,000 Btu/day) to over 3 billion Btu/day.
m or 1 foe) GAS OUT
WATER IN
ORGANIC SLURRY FERTILIZER
WASTE IN _—
SLURRY
BIOGAS DIGESTER PADOLE OR OTHER AGITATION
BIOGAS GENERATION
FIGURE E5.3-!
E 5-9
E.5.3.2 - Performance Characteristics
Energy output
Unless organic wastes (other than human) are available,
production for a village will be quite limited. For example,
based on a population of 100, an average human waste of 3
pounds/day, 11 percent solids in that waste, 84 percent of solids
being volatile (gas producing), production of 5 cubic feet of
biogas at 600 Btu/cubic foot per pound of volatile solids, the
theoretical biogas energy production is about 80,000 Btu/day,
equivalent to a heat content of six-tenths of a gallon of diesel
fuel per day.
Biogas generators can be designed for continuous or batch (4 days
- 2 weeks) operation, depending on the mode of digester loading
utilized.
The biogas producing digestive activities are optimal in two
temperature ranges: 85°-105° and 120°-140°F, although digestion
will occur from freezing to 156°F. Fermentation, however, is
less stable in the higher of these two ranges and, consequently,
the biogas units should usually be designed to be maintained in
the lower optimal range.
Typically, biogas generation in lower 48 climates requires
one-third to one-half of the enegy content of the gas generated
to heat the process. This efficiency of 50-67 percent could drop
to zero in severe Alaska climates.
Reliability
Need for backup
Fossil fuels displaced by the gasifier would typically be
used for backup
Storage requirements
The tank will permit a modest amount of gas storage in the void
above the digesting wastes.
Thermodynamic efficiency
65 percent to 95 percent conversion of fuel feedstock to usable
energy form.
Net energy
N/A
E 5-10
E.5.3.3 - Costs
Capital
N/A
Assembly and installation
N/A
Operation
N/A
Maintenance and replacement
N/A
Economies of scale
N/A
E.5.3.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
The waste feedstocks are water based slurries which are subject
to freezing in transport lines. Consequently, the digester
facility should be located as near to the waste source as
possible to minimize exposure to cold temperatures.
Resource needs
Renewable
Appropriate feedstocks for consideration are manure, fish
and shellfish wastes.
Non-renewable
N/A
Construction and operating employment by skill
Skilled construction and trained operating personnel are
required.
Environmental residuals
Solids: inert sludge
B51.
Health or safety aspects
The gas is highly flammable.
E.5.3.5 - Summary and Critical Discussion
Cost per million Btu or kWh
Lower 48 costs of a manure based commercial unit is projected at
$10,000 per 1,000 scf/d of capacity in smaller sizes to $3,000
per 1,000 scf/d for units in the range of 100,000 scf/d.
Resources, requirements, environmental residuals per million Btu or
kWh.
N/A
Critical discussion of the technology, its reliability and its
availability.
The application of biomass digesters is highly dependent upon the
availability and reliability of adequate feedstock materials.
Seasonal waste supplies will present problems of storage for
produced gas, (unless allowed to freeze and rethawed) as the
digestion process proceeds regardless of demand for gas.
Large quantities of waste must be available if a spark ignition
engine generator of reasonable size is to be fueled with biogas.
Assuming 500 Btu/scf gas production from a digester with an
efficiency of 75 percent, and a heating value of 5,000 Btu/1b for
the waste in the as produced condition, a 100 kW continuous
generator output from a 20 percent efficient machine would
require a continuous input of 256 lbs of waste per hour (93 tons
per month), exclusive of the gas requirement to maintain digester
tank temperture. Overall, application to Alaskan village
conditons would appear to be worth considering only under
exceptionally favorable circumstances.
£.5.4 - Waste Fired Boiler
E—.5.4.1 - General Description
While refuse (waste) can be used as an alternate boiler fuel, large
quantities are required on a continuous basis to justify the large
capital investment for a facility providing either heat or power. As
only the Anchorage (and possibly Fairbanks) area approaches the
production quantities required, this option is dismissed for the
villages.
E 5-12
E.5.5 - Peat
E.5.5.1 - General Description
Peat is an early stage in the transformation of vegetation to coal
and results from the partial decomposition and disintegration of
plant remains in the absence of air. Peat is generally formed in
water bogs, swamps, and marsh lands. Generally, peat is low in
nitrogen, sulfur, and ash.
A study to estimate Alaskan resource potential was recently performed
for the State of Alaska, Division of Energy and Power Development.
Numerous peat deposits were located and outlined in the study.
Undrained bog peat usually contains between 92 and 95 percent
moisture, but moisture is reduced to about 25 to 50 percent when peat
is harvested (by large earth moving equipment) and air dried. At
these reduced moisture levels, the bulk density of the resulting peat
is about 15 to 25 pounds/cubic foot and its heat value is
approximately 6,200 8tu/pound.
Wood is less difficult to gather and burn and contains a greater
heating value per pound. This has kept peat out of the energy market
in Alaska.
E.5.5.2 - Performance Characteristics
Performance is similar to burning low-grade coal.
E.5.5.3 - Costs
Peat-fired boilers require larger furnace volumes than are required
for gas, oil, or even low grade coal. Consequently, initial cost
will be greater. The harvesting and drying operation is also more
equipment and fuel intensive than coal. Investment and operating
costs will, therefore, be higher than for coal-fired plants on a per
kilowatt of capacity/kilowatt-hour generated basis.
E 6-1
E.6 - OTHER TECHNOLOGIES
£.6.1 - Binary Cycle for Electrical Generation
E.6.1.1 - General Description
Thermodynamic and engineering processes involved
The binary conversion process requires only heat quantity (heat
eneragy/unit time) and quality (temperature) to provide power. A
heated primary fluid of insufficient quality for direct use in
electrical production passes through a heat exchanger to transfer
heat to a working fluid. The working fluid has a lower boiling
point than water and is vaporized in the heat exchanger. The
vaporized working fluid then expands through a turbine, or in a
cylinder-piston arrangement, is condensed, and returns to the
heat exchanger. The primary fluid is returned to its heat source following heat exchanae. Figure £6.1-1 shows a generalized binary cycle.
Current and future availability
Binary cycle generation equipment in unit sizes suitable for
village applications are not expected to be available until the
late 1980's.
E.6.1.2 - Performance Characteristics
Energy output
Quality - temperature, form
Electricity
Quantity
A function of unit size
Dynamics - daily, seasonal, annual
Power can be generated whenever the heat source is
available.
Reliability
Need for back-up
When powered by waste heat, binary cycles are typically used
for peaking. If used for base loads, the binary-system would typically be backed up by the fossil system it displaces.
Storage requirements
Fuel storage requirements are those of the heat source technology.
PRIMARY FLUID
WORKING GENERATOR FLUID
HEAT EXCHANGER
CONDENSER
COOLING FLUID
GENERALIZED BINARY CYCLE
FIGURE E6.!-1
E 6-3
Thermodynamic efficiency
- around 10 percent to a reported 27 percent
- the organic Rankine diesel or Homing binary cycle can increase
plant output power by 15 percent
Net energy
3-10 units in to 1 unit out
E.6.1 3 - Costs
Capital
N/A
Assembly and installation
N/A
Operation
N/A
Maintenance and replacement
N/A
Economies of scale
Commercially utilized systems range from 1 to about 100 kW
£.6.1.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
Units are relatively small and light and require only an
enclosure and connection to the (nearby) heat source.
Resource needs
Binary cycles per se have no resource needs as heat is provided
from some other resource technology profiled herein. Hence,
solar geothermal, nuclear, and radiation, as well as any
combustion material, such as wood or coal are potential fuels.
Construction and operating employment by skill
Initial village installations would involve factory personnel for
most work. Operation can be relatively unattended, although a
qualified mechanic should be available.
E 6-4
Environmental residuals
Closed binary cycles in and of themselves cause no environmental
residuals; normal residuals are a result of the heat source.
Seal failure would cause leakage of the binary working fluid.
Health or safety aspects
Seal failures may cause release of gases which are generally toxic and/or flammable.
£.6.1.5 - Summary and Critical Discussion
Cost per million Btu or kWh
N/A
Resources, requirements, environmental residuals per million Btu or
kWh.
No resources are required other than those required for the
source of heat (typically diesel for engine-generators) nor are
any additional environmental residuals created.
Critical discussion of the technology, its reliability and its
availability
There are both domestic and foreign suppliers of appropriate size
binary cycle systems and product development is being vigorously
pursued.
Binary cycles for village electrical application could involve
so-called diesel "bottoming" - use of exhaust gas heat. Both
Rankine and Stirling cycle equipment in the less than 100 kW range are available and at least two manufacturers have sought
funding and assistance for an Alaska demonstration.
Binary bottoming cycle equipment is in operation in the
Trans-Alaska Pipeline utilizing waste heat to produce
electricity.
E.6.2 - Conservation
£.6.2.1 - General Description
Thermodynamic and engineering processes involved
Conservation measures considered here are mainly classified as
"passive". Passive measures are intended to conserve energy
E 6-5
without any further electrical, thermal, or mechnical energy
input. Typical passive measures are insulation, double glazing
or solar film, arctic entrances and weather stripping. Energy
conservation characteristics of some passive measure degrade with
time, which must be considered in the overall evaluation of their
effectiveness for an intended life cycle. Other conservation
measures include improvement in efficiency of utilization devices
(such as motors) and "doing without", energy by disciplines
(turning off lights, turning down thermostats).
Current and future availability
Passive measures are commercially available and increasing in use
all over the United States due to the rapidly escalating cost of
energy.
E.6.2.2 - Performance Characteristics
Energy output
Quality - temperatures, form
No energy output per se; rather a reduction of energy types
input.
Quantity
See above
Dynamics - daily, seasonal, annual
Passive conservation measures “operate” year round
Reliability
Need for back-up
None required
Storage requirements
None required
Thermodynamic efficiency
Not appropriate
Net energy
Not appropriate
E 6-6
E.6.2.3 - Costs
Capital
Residential installations run from several hundred to several
thousand dollars.
Assembly and installation
See above
Operation
None
Maintenance and replacement
Effectively maintenance free; 10-15 year life for major methods
Economies of scale
Amenable and appropriate to single dwellings or large industrial
complexes.
E.6.2.4 - Special Requirements and Impacts
Siting - directional aspect, land, height
No special requirements
Resource needs
Renewable
Solar insolation for passive solar methods
Non-renewable
Materials used for conservation modes employed.
Construction and operating employment by skill
Can often be installed by the resident; locally specialized
services (for example, insulation skills) may be employed. No
operation required.
Environmental residuals
Generally none. Excessive sealing of structures can produce
toxic or carginogenic gas concentraitons due to inadequate
ventilation.
E 6-7
Health or safety aspects
Care should be taken to assure proper air change rates for
occupant health.
£.6.2.5 - Summary and Critical Discussion
Cost per million Btu or kWh
N/A
Resources, requirements, environmental residuals per million Btu or
kWh.
N/A
Critical discussion of the technology, its reliability and its
availability.
Residences generally require the availability of energy at all
times. Before 1973, the cost of household energy was 3 to 10
percent of total annual expenses; now that percentage has soared
to perhaps 40 percent.
Although some dynamic measure (notably solar energy) merit
consideration in this class of structure, the prime emphasis
should be on passive energy conservation measures. As a whole,
this market is not geared to sophisticated or costly equipment or
to any measure that requires special operating or maintenance
procedures or attention. Generally, simplicity and low cost,
with moderate energy benefits, should be pursued.
The State of Alaska has high interest in energy conservation by
weatherization (passive conservation), particularly for
residences. The State has a $5,000, 5 percent loan program for
upgrading residences for conservation of energy.
APPENDIX
F - SAMPLE VILLAGE TECHNOLOGY ASSESSMENT
F - SAMPLE VILLAGE TECHNOLOGY ASSESSMENT
The following illustrates application of the Cost and Resource Criteria of the Technology Screening Methodology
discussed in Section C, as applied to the City of Galena.
(1) Coal-Fired Steam Costs:
Resources:
(2) Wood-Fired Steam Costs:
Resources:
Investment - maximum expected load less than 1 MW: investment wil]
probably exceed $5,000/kW - 1 pt.
Operating - expect $200,000/yr; O&M assume 400 kW average load = 3.5 x 10° kbh/year ($22 = $71,000/GWh) = 1 pt.
Fuel - shipping costs and purchase at Healy mine expected to result
in $140 - 150/ton price (or approx. 80 percent of oil); multiply times
estimated heat rate of 20,000 Btu/kWh, divide by 15,000 for diesel;
use factor of 1 pt.
Energy - coal available by barge from Nenana; 7 pts.
Socioeconomic - no infrastructure exists to staff, run, repair coal-
fired steam plant; 0 pts.
Investment - costs expected to be 20 percent higher than coal; 1 pt.
O&M - operating costs expected to be 10 - 20 percent higher than
coal; 1 pt.
Fuel - cost of gathering and processing wood: present price per cord
is roughly equal to $6/106Btu (or half oil) no outside market, some
sensitivity to oil price for transport - 2 pts.
Energy - wood available in surrounding area and downstream - but tree
growth is slow, limiting renewal rate; 7 pts.
Socioeconomic - as with coal, no infrastructure to run plant; 0 pts. Led
(3) Geothermal
(4) Diesel
(5) Gas Turbine
(6) Hydroelectric
Costs:
Resource:
Costs:
Resource:
Costs:
Resource:
Costs:
Investment - initial costs will likely exceed $5,000/kW; 1 pt.
Operating - O&M costs will be as significant as with coal or wood -
can expect well operating problems; 1 pt.
Energy - limited value resource available miles away towards Ruby;
1 pt.
Socioeconomic - no infrastructure to build, operate or repair plant
exists; O pts.
Investment - available capacities well matched to load, $800/kW;
4 pts.
O&M - annual costs for diesel approach $100,000/GWh; 1 pt.
Energy - Oil fuel imported; 7 pts.
Socioeconomic - Diesels presently operated; 2 pts.
Investment - approaches $1,000/kW if 800 kW capacity required, but
for Galena, inadequate load until 1990's; 2 pts.
O&M - O&M costs will be equal to diesel in general magnitude because
of reduced demand compared to capacity; 1 pt.
Fuel - lower efficiency at part load will increase per kWh fuel costs
over diesel; 0 pts.
Energy - imported fuel; 7 pts.
Socioeconomic - questionable support skills for O&M; 1 pt.
Investment - Kalakaket Creek estimated $15 - $20,000 per kW; 0 pt.
O&M - unattended plant expected, perhaps $5,000/year expense and say $5,000 annual replacement for 760 kW plant - perhaps $3,000/GWh; pts.
(6)
(7)
(8)
Hydroelectric (contd)
Wind
Photovoltaic
Costs:
Resources:
Costs:
Resources:
Costs:
Resources:
Fuel - none; 3 pts.
Energy - Creek freezes in winter and installation may be available
only 4 - 5 months of year; 3 pts.
Socioeconomic - limited skills needed for unattended plant - diesel
operator level; 2 pts.
Investment - installed costs per rated kW of close to $5,000/kW; with
Tow average wind of Galena cost would exceed $10,000/avg. kW; 0 pts.
O&M - expect more maintenance than with hydro - estimate $5 - $8,000
+ $15,000 replacement year (for 200 kW unit); at 20 percent capacity
factor = $62,000/GWh or 62¢/kWh; 1 pt.
Fuel - none; 3 pts.
Energy - Galena wind resources are poor - avg. windspeed
approximately 3.9 mph/high of 4.6 (avg.) in spring. Storms bring
higher winds; 1 pt.
Socioeconomic - city should be able to support a WIG; 2 pts.
Investment - over $20,000/peak kilowatt expected, even with storage
removed; 0 pts.
O&M - estimate negligible-maintenance perhaps $500/year; replacement
cost = $6,700, thus $7,200/yr; if 25 percent capacity factor (CF) on
devices - (include clouds and rain, derate for latitude in winter),
yields $660,000/GWh; at 100 percent CF = $164,000/GWh or 16.4¢/kWh;
0 pts.
Fuel - none; 3 pts.
Energy - Limited by night/day, cloud cover, winter sun - no storage
assumed for system, unreliable source; 2 pts. to be generous u Socioeconomic - no problems foreseen = 2 pts. €=3
(9) Diesel Waste Heat
(10) Electric Resistance
(11) Passive Solar
Costs:
Resources:
Costs:
Resources:
Costs:
Investment - existing Galena system cost $325,000 to heat three
buildings, presently undergoing startup; capacity estimated at
2 million Btu/hr; 175,000/106 Btu/hr residential heat load estimate
is 20,000 Rtu/hr peak for typical house, thus "cost per home" =
$3,500 = 1 pt.; since already installed; 4 pts.
O&M - annual O&M costs expected to be approximately $7,000/year and
replacement of $13,000 = $20,000; heat production - est. 25 percent
“capacity factor" or 3.2 GWh of heat/year = $/GWh of 6,200; 3 pts.
Fuel - none; 3 pts.
Energy - within the limits of the generating plant capacity,
avai tobi lity is excellent with the system already in place and
doubtfully fully loaded; 9 pts.
Socioeconomic - capable of support; 2 pts.
Investment - 4 pts.
O&M - 4 pts.
Fuel - electricity is most expensive form of energy available; 0 pts.
Energy - generating capacity is limited - off peak energy available
in some quantity but not enough to heat more than a few homes
intermittently; 2 pts.
Socioeconomic - no problems foreseen; 2 pts.
Investment - retrofit to existing homes expected to cost upwards of
$10 - $15,000, therefore, not considered; new homes might include
passive design features which would be useful in summer at less than
$5,000; 2 pts. for new homes only.
O&M - generally negligible for operation, house replacement normally Ts not considered by homeowner; 4 pts. v-4
(11) Passive Solar (contd) Costs:
Resources:
(12) Wood Costs:
Resources:
(13) Coal Costs:
Resources:
Fuel - none; 3 pts.
Energy - northern latitude limits winter usefulness; only new homes
considered; 2 pts.
Socioeconomic - although lifestyles might be altered, no problems seen
in absorbing technology if included in new home design package; 2 pts.
Investment - wood stove kits range from $50 (to modify oil drums to short
life/high efficiency systems) up to $1,000; 4 pts.
O&M - periodic cleanout, flue cleanout required; 3 pts.
Fuel - wood estimate at $100/cord is approximately 1/2 price of oil;
2 pts.
Energy - as with wood fired steam - local resources limited by growth
rates; 7 pts.
Socioeconomic - established heating method; 2 pts.
Investment - stove designs available at costs up to $10,000 for fully
automated feed and ash discharge; 3 pts.
O&M - similar to wood; 3 pts.
Fuel - cost from Nenana approaches the price of oil; 1 pt.
Energy - available via Yutana Barge; 7 pts.
Socioeconomic - no existing system in village for large scale handling,
warehousing, etc.; 1 pt. S-4
(14) 011
(15) Coal Gasification
(16) Wood Gasification
Costs:
Resources:
Costs:
Resources:
Costs:
Resources:
Investment - Existing stove designs in use and available at less than
$1,000 per unit; 4 pts.
O&M - ininimum annual expenses replacement and maintenance less than $1,000/yr; 4 pts.
Fuel - oil; 1 pt.
Energy - imported; 7 pts.
Socioeconomic - existing system; 2 pts.
Investment - small scale requirements from a large scale technology;
0 pts.
O&M - large scale expenses for commercial size equipment; 0 pts.
Fuel - poor efficiency compared to direct coal fired steam; 0 pts.
Energy - Yutana Barge; 7 pts.
Socioeconomic - no existing capability to support technology in city; 0 pts.
Investment - Marenco estimate for 250 kW gasifier diesel system approaches or exceeds $2,000/kW with all equipment; 3 pts.
O&M - full time operator required, plus fuel handler - 2 men x 168 hr/wk x 52 wks/yr x $20/hr = $350,000 + add perhaps $100,000 for
maintenance = $450,000. Generation @ 70 percent C.F. = 1.5 GWh, or
$300,000/GWh; 0 pts.
Fuel - wood, as before; 2 pts.
Energy - availability as before; 7 pts.
Socioeconomic - no capability to operate gasifier exists, no service
structure exists; 0 pts. or
(17) Biogas
(18) Waste-Fired Boiler
(19) Peat
Costs:
Resources:
Costs:
Resources:
Costs:
Investment - as minimal materials are available as feedstock, output
will be very small for initial response; 0 pts.
O&M - minimal expenses, but still significant compared to expected
output; 3 pts.
Fuel - were it available, nearly free; 3 pts.
Energy - too little to make it worthwhile; 0 pts.
Socioeconomic - systems are simple, within city capabilities; 2 pts.
Investment - modular systems are available, but in sizes much larger
than can be supported. 40 tons/day will produce approximately 4,000
lbs/hr of low pressure steam around the clock - and facility will
cost close to $3 million or $300,000 per GWh of heat; therefore, use
0 pts.
O&M - full time operator required, plus significant maintenance is
typical; 0 pts.
Fuel - refuse/garbage must be collected from all homes and sorted for
most systems; 2 pts.
Energy - population is inadequate to support any economical waste to
energy facility; O pts.
Socioeconomic - operation and maintenance skills, service support ee ; existing in village or nearby are inadequate; 0 pts.
Investment - boilers are more expensive than for wood; harvesting,
drying and storage equipment will not be cheap; 0 pts.
O&M - operating costs will involve one full-time and probably one
part-time employee (1/2 man) per shift, plus significant regular
maintenance, high capital cost results in high replacement expense;
0 pts. iss
(19) Peat (contd) Costs:
Resources:
(20) Binary Cycle Generator Costs:
Resources:
(21) Conservation Costs:
Resources:
Fuel - assuming location is nearby, harvesting labor and fuel used
for drying will be significant expenses, particularly for smal]
operation. Boiler efficiency is also expected to be low; 1 pt.
Energy - Ekono report indicates peat may exist in area. A generous
3 pts.
Socioeconomic - No existing trained workforce to gather peat, no
source Of equipment or maintenance; 0 pts.
Investment - initial costs are very high - often approach and likely
to exceed $10,000/kW for equipment only; 0 pts.
O&M - some maintenance or inspection expected on a daily basis - but
minimal; 3 pts.
Fuel - "Free" energy; 3 pts.
Energy - waste heat already used in Galena but some might be
available; 3 pts.
Socioeconomic - runs basically unattended; as unit would not be a
critical item adequate support should be available; 2 pts.
Investment - minimal investments are expected to produce major
savings in many Galena homes; 4 pts.
O&M - annual inspection generally will be adequate; 4 pts.
Fuel - none; 3 pts.
Energy - waste energy savings; 9 pts.
Socioeconomic - minimal instruction would be all that is required -
materials generally easy to obtain and apply. (Major fixes such as
wall/ batt insulation are not being considered in this instance but
are also possible.) 2 pts.
(22) Regional Hydro - Costs: Investment - if load exists, cost per usable kilowatt can fall to
Melozitna River $15,000 range; 0 pts.
O&M - plant can be largely unattended or with one operator, yet
remain in 4 pt. category (including replacement expense)
Fuel - renewable and "free"; 3 pts.
Resources: Energy - site is available but somewhat distant; 7 pts.
Socioeconomic - no existing infrastructure to build, operate or
service plant; 0 pts. 6-4
F-10
TABLE 1
VILLAGE TECHNOLOGY ASSESSMENT
FOR
GALENA
TECHNICAL COST RESOURCE
FACTORS FACTORS
TECHNOLOGY
Electric
Coal Fired Steam
Wood Fired Steam
Geothermal
Diesel (base)
Gas Turbine
Hydroelectric
Wind
Photovoltaic own pr F&F KF fF nyo FY FF ww BF Fe mor rF OH YF CO CoO ON PK Ke oOo Fr FP RP RR Re wWwwwodre wNDr we Nr WN NPY NN nm ne HY CO OO Ts
as
3
4.
Be
6.
1
8.
Heating
Diesel Waste Heat Recovery
Electric Resistance
Passive Solar
Wood
Coal
Oil (base)
Other
Coal Gasification
Wood Gasification - Diesel
Biogas
Waste Fired Boiler
Peat
Binary Cycle Generator
Conservation a nr & FW Fe Ww ON NFP KF DY BH Be oN NM OO NM KF CO oP OOO OW Oo PrP FP WwW OoOOwW oO Oo WwW We % WH NM WOW WWOON N So Wm: 2 Oo 9 (oc ro Regional Hydro
NOTE: Higher numbers are more favorable.
BIBLIOGRAPHY-1
BIBLIOGRAPHY
1
3:
4,
10.
Le
12s
132
Alaska Department of Commerce and Economic Development, Division of
Energy and Power Development. 1981 State of Alaska Long Term Energy
Plan, 1981.
Alaska Department of Community and Regional Affairs, Divison of
Community Planning. Community Profiles for Gustavus, Karluk,
Stebbins, St. Michael, Unalakleet, Koyuk, Golovin, Teller, Brevig Mission, Little Diomede, Shishmaret and Atkasook.
Alaska Department of Transportation and Public Facilities. Alaskan
Wind Energy Handbook, 1981.
Battelle. Alaskan Electric Power, An Analysis of Future Requirements
and Supply Alternatives for the Railbelt Region, 1978.
R. W. Beck and Associates. Small-Scale Hydropower Reconnaissance
Study Southwest Alaska, 1981.
CH2M Hill. Regional Inventory and Reconnaissance Study for Small
Hydropower Sites in Southeast Alaska, 1979.
Dames and Moore. Assessment of Coal Resources of Northwest Alaska,
1980.
Ebasco Services Inc. Regional Inventory and Reconnaissance Study for
Small Hydropower Projects Aluetian Islands, Alaska Peninsula, Kodiak Istand, Alaska, 1980.
Ekono Inc. Peat Resource Estimation in Alaska, 1980.
Mark Fryer. Utility and Environmental Planning for the Townsite of
Atkasook, Alaska, ToT
Geo-Heat Utilization Center. Geothermal Energy in Alaska: Site Data
Base and Development Status, 1977.
Holden and Associates. Reconnaissance Study of Energy Requirements
and Alternatives for Kaltag, Savoonga, White Mountain, Elim, 1981.
Grant and Ireson. Principles of Engineering Economy, 1976.
14.
15%.
16.
fs
18.
19.
20.
eave
22.
23)
24,
25.
26.
Cie
BIBLIOGRAPHY-2
International Engineering Company Inc. Reconnaissance Study of Ener
Requirements and Alternatives for Buckland, Chathbaluk, Crooked treet
Hughes, Koyukuk, Nikolai, Red Devil, Russian Mission, Sheldon Point,
STeetmute, Stony River, ltakotna and Telida, 1981.
Joint Federal-State Land Use Planning Commission. Forest Resources of
the South Central Region, 1974,
Kramer Associates/Kevin Waring Associates. Rural Energy: Problems
and Prospects, 1981.
Marks Engineering, Brown and Root, Inc. Reconnaissance Study of
Energy Requirements and Alternatives for Tanana, 1981.
Northern Technical Services. Reconnaissance Study of Energy
Requirements and Alternatives, Togiak, Goodnews Bay, Scammon Bay and
Gray ing, 198T.
Ott Water Engineers, Inc. Regional Inventory and Reconnaissance Study
for Small Hydropower Projects Northwest Alaska, 1981.
Reid, Collins Alaska Inc. Use of Wood Energy in Remote Interior
Alaskan Communities, 1981.
Robert W. Retherford Associates. Long Range Utility Master Plan for
North Slope Borough, Draft Report, TBI.
Robert W. Retherford Associates, Howard Grey Associates, Jack West
Associates. Project Planning Report, Barrow-Atgqasuk-Wainwright
Transmission Line, 1081.
Robert W. Retherford Associates. Waste Heat Capture Study for State
of Alaska, 1978.
U. S. Army Corps of Engineers. Feasibility Studies for Small Scale
Hydropower Additions, 1979.
U. S. Army Corps of Engineers, North Pacific Division - Portland
District. Hydropower Cost Estimating Manual, May 1979.
U. S. Department of Energy. Hydroelectric Plant Construction Cost and
Annual Production Expenses - 1978, 1979.
University of Alaska, Institute of Social and Economic Research. The
Impact of Rising Energy Costs on Rural Alaska, 1980.
28.
29.
BIBLIOGRAPHY -3
Wind Systems Engineering. Shungnak, Kiana, and Ambler Reconnaissance
Study of Energy Requirements an Alternatives, 1901.
Arthur Young and Company. A Concept for Power Production Assistance to Electric Utilities, 1980.