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Executive Summary to Volume IV
Candidate Electric Energy
Technologies for Future
Application in the Railbelt
Region of Alaska
Volume III
November 1982
Prepared for'the Office of the Governor
State of Alaska
Division of Policy Development and Planning
and the Governor's Policy Review Committee
under Contract 2311204417
C)Battelle ,
Pacific Northwest Laboratories
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LEGAL NOTICE
This report was prepared by Battelle as an account of sponsored
research activities.Neither Sponsor nor Battelle nor-any person acting
on behalf of either:.
MAKES ANY WARRANTY OR REPRESENTATION,EXPRESS OR
IMPLIED,with respect to the accuracy,completeness,or usefulness of
the information contained in this report,or that the use of any informa-
tion,apparatus,process,or composition disclosed in this report may not
infringe privately owned rights; or
Assumes any liabilities with respect to the use of, or for damages result-
ing from the use of, any information,apparatus,process,or composition
disclosed in this report.
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CANDIDATE ELECTRIC ENERGY TECHNOLOGIES FOR FUTURE
APPLICATION IN THE RAILBELT REGION OF ALASKA
Executive Summary
Volume III
November 1982
Prepared for the Office of the Governor
State of Alaska
Division of Policy Development and Planning
and the Governor's Policy Review Committee
under Contract 2311204417
Battelle
Pacific Northwest Laboratories
Richland,·Washington 99352
L~_~_
RAILBELT ELECTRIC POWER ALTERNATIVES STUDY
Volume I -Railbelt Electric Power Alternatives Study: Evaluation of
Railbelt Electric Energy Plans
Volume II -Selection of Electric Energy Generation Alternatives for
Consideration in Railbelt Electric Energy Plans
Volume III - Executive Summary - Candidate Electric Energy Technologies
for Future Application in the Railbelt Region of Alaska
Volume IV - Candidate Electric Energy Technologies for Future Application
in the Railbelt Region of Alaska
Volume V -Preliminary Railbelt Electric Energy Plans
Volume VI -Existing Generating Facilities and Planned Additions for the
Railbelt Reqion of Alaska
Volume VII -Fossil Fuel Availability and Price Forecasts for the Railbelt
Region of Alaska
Volume VIII -Railbelt Electricity Demand (RED)Model Specifications
Volume VIII -Appendix -Red Model User's Guide
Volume IX Alaska Economic Projections for Estimating Electricity
Requirements for the Railbelt
Volume X Community Meeting Public Input for the Railbelt Electric
Power Alternatives Study
Volume XI -Over/Under (AREEP Version)Model User1s Manual
Volume XII - Coal-Fired Steam-Electric Power Plant Alternatives for the
Railbelt Region of Alaska
Volume XIII - Natural Gas-Fired Combined-Cycle Power Plant Alternative for
the Railbelt Region of Alaska
Volume XIV -Chakachamna Hydroelectric Alternative for the Railbelt Region
of Alaska
Volume XV -Browne Hydroelectric Alternative for the Railbelt Region of
Al aska
Volume XVI -Wind Energy Alternative for the Railbelt Region of Alaska
Volume XVII -Coal-Gasification Combined Cycle Power Plant Alternative for
the Railbelt Region of Alaska
iii
TABLE OF CONTENTS
INTRODUCTION • • • • • • • • • • • • • . • . •••1
COAL-FIRED STEAM-ELECTRIC GENERATION • • • • • • • .0 ••3
NATURAL GAS AND DISTILLATE-FIRED STEAM-ELECTRIC GENERATION.•••7
BIOMASS-FIRED STEAM-ELECTRIC GENERATION.•••••••11
NUCLEAR LIGHT WATER REACTORS.• • • • • • • • • • •15
GEOTHERMl\L GENERATION • • • .0 • • •19
PEAT-FIRED STEAM-ELECTRIC GENERATION • • •0 • • • • •••23
COMBUSTION TURBINES.0 •• •• •• • •• • •• •••27
COMBINED-CYCLE POWER PLANTS • • • • • • • • • • • •31
DI ESEL GE NE RATION • • • • • •• • • • ••.35
CONVENTIONAL HYDROELECTRIC • • ••••••••39
.FUEL CELLS.• • • • •• • • • • .•.47
STORAGE TECHNOLOGIES • • • • • • • • • • • •••51
PUMPED HYDROELECTRIC •••••••.•••51
STORAGE BATTERIES.• • • • • • • • • • • • •••53
COMPRESSED AIR ENERGY STORAGE (CAES)• • • • • • •54
COGENERATION • • • • • • • • • • •••••••57
TIDAL POWER • . • • • • • ••••••59
LARGE WIND ENERGY SYSTEMS.••••••••63
SMALL WIND ENERGY SYSTEMS.• • • • • • • • • • • •67
SOLAR ELECTRIC POWER • • • • • • • • • • • •••71
SMALL HYDROELECTRIC AND MICROHYDROELECTRIC POWER • • • • •75
LOAD MANAGEfiE NT • • • • • • • • • • • • • • •0 77
ELECTRIC ENERGY CONSERVATION IN BUILDINGS • • •81
ELECTRIC ENERGY SUBSTITUTES • • • • • •83
PASSIVE SOLAR SPACE HEATING • • • . • • • • • •0 0 83
ACTIVE SOLAR SPACE AND HOT WATER HEATING ••••85
WOOD-FIRED SPACE HEATING • • • • •87
v
L
·INTRODUCTION
The State of Alaska commissioned Battelle,Pacific Northwest Laboratories
in its Railbelt Electric Power Alternatives Study to investigate potential
strategies for future electric power development in Alaska's Railbelt region.
The results of the study will be used by the Office of the Governor to
formulate recommendations for electric power development in the Railbelt.
The primary objective of the study is to develop and analyze several
alternative long-range plans for electric energy development in the Railbelt
region.Each plan is based on a general energy development strategy
representing one or more policies that Alaska may wish to pursue.The analyses
of the plans will produce a forecast of electric energy demand,a schedule for
developing generation and conservation alternatives,an estimate of the cost of
power,and a discussion of the environmental and socioeconomic characteristics
for each plan.
In the development of these plans,38 electric energy alternatives to be
included as potential future Alaskan sources were identified (Table 1).Eight
of these were identifi ed to be inappropri ate for further cons iderat ion either
for technical or availability reasons.This report,Volume III of
seventeen volumes (see page iii),summarizes the study findings on the 30
remaining energy alternatives.Except for solar electric power and load
management,where the discussion of alternatives within these two categories
has been consolidated,the summary of each alternative typically contains a
discussion of the following areas:a general description of the alternative,
possible Railbelt applications,commercial availability,conversion efficiency
(or performance), estimated cost of power,resource availability,environmental
consequences,and socioeconomic consequences.
The estimated cost of power for each alternative is presented as levelized
lifetime costs for 1990 operation in 1980 dollars,using a 3%discount rate.
Costs are adjusted for the Alaskan construction cost environment.Further
technical detail for each alternative can be found in Volume IV of this report
series.Additional information on fuel price is available in Appendix B in
Volume IV and in Volume VII of this report series.
1
TABLE 1. Candidate Electric Energy Alternatives
Baseload Generating,Alternatives
Coal-Fired Steam-Electric Generation
Natural-Gas/Distillate-Fired Steam-Electric Generation
Biomass-Fired Steam-Electric Generation
Peat-Fired Steam-Electric Generation
Combined-Cycle Plants
Magnetohydrodynamic Generators
Nuclear Light Water Reactors
Fast Breeder Fission Reactors
Geothermal Generation
Fusion Reactors .
Ocean Current Energy Systems
Salinity Gradient Energy Systems
Ocean Thermal Energy Conversion System
Space Power Satellites
Baseload/Load-Following Generating Alternatives
Combustion Turbines
Diesel Generation
Conventional Hydroelectric
Small Hydroelectric and Microhydroelectric
Fuel Cells
Fuel-Saver (Intermittent)Generating Alternatives
Ocean Wave Energy Systems
Tidal Power
Large Wind Energy Systems
Sma 11 Wind Energy Systems
Solar Photovoltaic Systems and Solar Thermal or Control
Receiver Systems
Cogeneration
Energy Storage Alterantives
Pumped Hydroelectric
Storage Batteries
Compressed Air Energy Storage
Load Management
Direct Load Control
Passive Load Control
Incentive Pricing
Education and Public Involvement
Dispersed Thermal Energy Storage
Electric Energy Conservation in BUildings
Electric Energy Substitutes
Passive Solar Space Heating
Active Solar Space and Hot Water Heating
Wood-Fired Space Heating
Candidate
Electric
Energy
Alternative
Yes
Yes
Yes
Yes
Ye~Nola)
Yes
No
Yes
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Selection Criteria
Conmercial Technical
Availability Feasibility
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
2000-2005 Yes
Available Yes
2005-2025 Yes
Available Yes
2025 Yes
Beyond 2000 No (Resource Limited)
Beyond 2000 No (Resource Limited)
2000 No (Resource Limited)
Beyond 2000 No (Resource Limited)
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
1990s No (Resource Limited)
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
Available Yes
(a)"No"indicates that this technology was not analyzed in the study.
2
COAL-FIRED STEAM-ELECTRIC GENERATION
A coal-fired steam-electric generating plant consists of a coal-fired
furnace and boiler to generate steam, a steam turbine-generator unit for
production of electric energy,and a condensor feedwater system to return
process water to the boiler.Also required are a flue gas pollution control
system to trap particulates and to control the emissions of sulfur oxides and
coal handling facilities to receive,store,and prepare the coa l for firing.
Available plant sizes range from 20 to 1200 MW;200-MW units appear to be
appropriate for Railbelt applications.
POSSIBLE RAILBELT APPLICATIONS
Coal is currently available from Nenana field near Healy and is
potentially available from the Beluga field east of Cool Inlet.Coal-fired
generation shows promise as a major source of baseload power in the Railbelt
region.Units are already operating in the region (Healy,Chena,University
of Alaska).The size range of most interest in the Railbelt system is 20 to
200 MW.These units,as well as larger sizes,are commercially available.
Mine-mouth generation would have the advantage of minimizing transportation
and storage costs and impacts, but these gains would be partially offset by
the requirement for longer transmission facilities.
COMMERCIAL AVAILABILITY
Coal plants and their associated pollution control equipment are
commercially available.Some special provisions may have to be made for cold
weather operation of coal handling and scrubber equipment,but this is not
considered a major complication.Acoal plant can be constructed in 7 years,
including time to obtain necessary permits.A plant could be on line by 1989
with a 1982 decision to build.A 20-MW unit could be constructed in a shorter
time if the boiler were a package design and auxiliary equipment were skid
mounted.
3
.~.~--------------------------------
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CONVERSION EFFICIENCY
The conversion efficiency of coal-fired plants varies with unit size and
the scrubber system used. A range of efficiencies from 26 to 36%can be
expected with units from 20 to 600 MW capacity,respectively.
ESTIMATED COST OF POWER
Estimated electric energy costs are shown below for 200-MW plants
operating at a 29%conversion efficiency and a 65%capacity factor.Smaller
plants would demonstrate higher costs.Some cost savings would be realized in
plants larger than 200 MW.
The cost components are as follows:
Capita 1
Fuel
Operating and Maintenance
Total Production Cost
Coal-Fired Steam-
E1ectr i c (mi 11 s IkWh )
Beluga Nenanna
23 23
27 30
7 7- -
57 60
Approximately 50%of the capital expenditures of a coal-fired plant would
flow outside the Railbelt,but only 10%of the operating and maintenance costs
would leave the region.Fuel would be purchased within the region.
ENVIRONMENTAL CONSEQUENCES
Coal-fired power plants generate large quantities of solid waste derived
from the combustion process.These wastes include fly ash and bottom ash.
The desulfurization of stack gases generates more solid wastes. All of these
wastes require careful disposal to ensure the protection of water resources.
The combustion of large amounts of coal potentially leads to a
significant deterioration of the local air quality.Therefore,siting of
future plants using Nenana coal will probably be either to the north or south
4
of these coal deposits to meet the Class 1 air-quality standards that apply in
Denali National Park.Because Alaskan coal is generally very low in sulphur,
Class 2 standards should not be difficult to meet with commercially available
scrubbing equipment.
Because of the large land area needed for construction and operation,
preemption or alteration of terrestrial biota habitat can be a significant
environmental impact at some sites.These land requirements are generally
greater than those for other types of fossil-fueled power plants.
Coal-fired plants will use the same,or less,water per unit of capacity
than any other thermal plant except a combined-cycle facility.A 200-MW plant
(a suitable plant size for the Railbelt)would require about 90,000 gpm for a
once-through cooling system or 1,800 gpm for a recirculating system.Waste
water from ash transport and flue gas desulfurization processes demand
sophisticated treatment to reduce toxicity to aaceptable discharge levels.
Zero discharge plant designs are available.
SOCIOECONOMIC CONSIDERATIONS
A 200-MW plant is estimated to require a construction work force of 600
and an operating work force of 85. For a 200-MW plant,any community other
than Anchorage would experience a severe strain on community services,
schools,and housing during the construction period.
5
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NATURAL GAS AND DISTILLATE-FIRED
STEAM-ELECTRIC GENERATION
Natural gas and oil-fired steam-electric plants are similar in concept to
coal-fired steam-electric plants except natural gas or distillate fuel oil is
used to fire the furnace to generate steam. Flue gas pollutant control
systems and fuel and solid waste handling systems are typically less complex.
Available plant sizes range from 10 to 200 MW.The 200-MW units appear
to be appropriate for Rai1be1t applications.
POSSIBLE RAILBELT APPLICATION
Oil-fired steam-electric plants may be fueled with either distillate (#2)
or residual (#6) fuel oil.Residual fuel oil is typically less expensive but
often requires use of flue gas desu1furization equipment.
The present sources of fuel oil in the Rai1be1t are confined to the
refineries of Kenai and Fairbanks. Petroleum pipelines carry imported refined
products from the port at Whittier to Anchorage.Because the fuel refining or
pipeline transmission systems are already in place,these areas are prime
sites for plant construction.Gas-fired units can be located near wells or
gas pipelines.The Anchorage,Cook Inlet,and Kenai regions are well suited
in this respect.
COMMERCIAL AVAILABILITY
Natural gas and distillate-fired steam-electric plants are a conmercia11y
available mature technology.The Powerp1ant and Industrial Fuel Act of 1978
(PIFUA),however,prohibits the use of oil or natural gas for continuous duty
generating units exceeding 10-MW capacity.Exemptions under PIFUA may be
granted only when a utility can show that no reasonable alternatives exist.
The possibility exists that synthetic or gaseous fuels may be derived from
coal in the future (these fuels would be exempt from the restrictions of
PIFUA)•
7
L .~_
CONVERSION EFFICIENCY
Units of this type exhibit a conversion efficiency that ranges from 28 to
30%.
ESTIMATED COST OF POWER
The cost of power is a function of both the size of installation and fuel
type.Distillate fuel-fired plants require more storage and pollution control
equipment than do the gas-fired plants.Estimated costs for 200-MW distillate
fuel oil and natural gas-fired steam-electric plants operating at 31 and 30%
conversion efficiencies,respectively,and a 65%capacity factor are as
fo 110ws:
Capital
Fuel
Operating and Maintenance
Total Production Cost
Distillate
Oil
(mi 11 s/kWh)
13
103
4
120
Natural Gas
(mills/kWh)
9
48
4
61
An estimated 70%of the plant capital costs and 16%of operation and
maintenance costs would be spent outside of Alaska.Fuel would be purchased
within the region.
ENVIRONMENTAL CONSEQUENCES
A 200-MW capacity distillate plant would require 20 acres compared to
13 acres for gas,respectively.The difference is due to the distillate tank
storage facilities.Water requirements are about the same as those for other
thermal plants of the same size.
Of all combustion processes,air pollution problems are the least when
gas is burned.If residual fuels are used, stack scrubbers may have to be
installed to remove sulphur dioxide.Nitrogen oxide emissions may be
significant enough to require control techniques such as two-stage
combustion.
8
The impacts on aquatic species caused by cooling water intake and
discharge systems will be about the same as any other comparably sized
combustion steam generating plant.A minimal impact on terrestrial biota can
be expected from the loss of habitat.
SOCIOECONOMIC CONSIDERATIONS
A 200-MW plant is estimated to require a peak construction force of 580
and an operating force of 70.These work forces could strain facilities,
particularly housing, in many of the small communities along distribution
pipelines.
9
L~_
BIOMASS-FIRED STEAM-ELECTRIC GENERATION
Biomass fuels available in the Railbelt region for power generation
include sawmill wood waste and fuel derived from municipal waste.Small
quantities of waste oil are also available.Wood waste has been used as an
energy source for many years,particularly in the timber industry.Use of
refuse-derived fuel is a more recent concept and is less well developed in the
United States.
POSSIBLE RAILBELT APPLICATIONS
In the Railbelt region,biomass power plants using municipal refuse
supplemented by wood residue and coal potentially may contribute up to 5%of
future power needs.These units would be central station plants serving
single load centers or connected to a Railbelt power grid.Relatively small
plants at Anchorage and Fairbanks may be feasible,making full use of the
municipal refuse,waste oil,wood residue,and supplemental coal available in
the respective areas.
COMMERCIAL AVAILABILITY
Direct-fired steam-electric plants that are designed to use biomass fuels
as the primary feed material or that have the capability to be supplemented by
fossil fuels are commercially operating.Processes for converting biomass to
a gas as fuel for power heat and power generation could be available in five
years.Wood-to-methanol (wood alcohol)plants are commercially available,
while herbage-to-methanol processes remain to be demonstrated.
CONVERSION EFFICIENCY
The typically high moisture content of biomass fuels and small scales of
operation introduce thermal inefficiencies into a biomass-fueled power plant.
Heat rates can range between 20,000 Btu/kWh and 14,000 Btu/kWh for rated
capacities of 5 and 50 MW,respectively.(This compares to heat rates of
9,000 Btu/kWh for many coal-fired plants.)Operated as base-loaded units,
biomass facilities have demonstrated high reliability.
11
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ESTIMATED COST OF POWER
The power costs of dual,direct-fired refuse/coal electric-generating
plants of 25-MW rated capacity and 24%conversion efficiency in Anchorage and
20-MW rated capacity in Fairbanks are estimated to be 67 and 78 mills/kWh,
respectively.The cost components are as follows:
Capital
Fuel
Operations and Maintenance
Total Prpduction Cost
Biomass -F ired
Anchorage
(mills/kWh)
32
o
35
67
Steam-Electric
Fairbanks
(mi 11 s/kWh)
36
7
35
78
The high construction costs of small-scale biomass power plants are a major
factor in the relatively high power costs of this option.Coal is used as a
supplement to refuse-derived fuel,with the latter proportion increasing over
the life of the facility.The capacity factor used in estimating costs for
these units is 65%.
RESOURCE AVAILABILITY
,
Potential sources of biomass fuels in the Railbelt region include mill
residue (bark chips,slabs,sawdust and planer shavings)from saw mills in the
area and municipal waste from Fairbanks and Anchorage.A major consideration
of using biomass for power generation is its availability near (within
approximately 50 miles) the power plant.The high moisture content and low
bulk density of most biomass material make shipping it long distances for fuel
use economically prohibitive.
ENVIRONMENTAL CONSEQUENCES
Water resource impacts of biomass-fired power plants are not expected to
be significant because of the small plant capacities that are considered
likely.Proper siting and design of intake and discharge should minimize
12
withdrawal and discharge impacts.The burning of biomass could significantly
impact ambient air quality.Facilities of approximately 5-MW capacity or more
will require an air pollution control system that meets federal New Source
Performance Standards.Land requirements for biomass-fired plants are
expected to be similar to coal-fired plants.Because of the relatively small
plant capacities involved, the impact on the terrestrial biota is expected to
be minimized through the plant siting process.
SOCIOECONOMIC CONSIDERATIONS
A relatively small labor force is required to construct and operate
biomass-fired facilities.For 15- to 30-MW plants,a construction and
operating staff would be approximately 65 and 25,respectively.The effect of
plant construction and operation in the Anchorage,Fairbanks,and Soldotna
areas would be minimal,while the impact on smaller communities,such as
Nenana,could be significant.
13i;
I;
~.1 _
NUCLEAR LIGHT WATER REACTORS
Nuclear steam-electric generation converts heat generated in the
fissioning of uranium atoms into steam.The steam is used to drive turbine
generators,which generate electricity.Nuclear steam-electric generation has
two basic design concepts: the boiling water reactor (BWR)and pressurized
water reactor (PWR).Both concepts employ designs based on the use of natural
water ("light water") as the reactor coolant.In the BWR design, cooling water
circulates through the reactor core where it is heated to steam that is used
directly to drive the turbogenerator.In the PWR concept, water is heated
under high pressure in the reactor core.Steam used to drive the
turbogenerator is generated in a secondary heat exchanger in this concept.
POSSIBLE RAILBELT APPLICATION
Nuclear steam-electric generation is not considered applicable to the
Railbelt region,primarily because the available sizes of nuclear plants are
too large for forecasted Railbelt loads.Because of the large economies of
scale in nuclear technology,plant sizes are large.These plants are designed
for baseload operation and are available from domestic vendors in the 800 to
1200 MW range.Because the forecasted Railbelt interconnected load in 2010
would require a capacity of only 1800 MWe,even the smallest nuclear plant
would contribute about 50%of the total capacity requirement.Because of
reliability and reserve considerations,a plant exceeding 20%of the system
total capacity is not recommended.
In addition to the technical/economic considerations impacting the use of
nuclear power in Alaska,current State statutes specifically exclude nuclear
energy production from the definition of power projects that can be funded
through the Power Development Fund (see Power Authority Act as amended
4483 •230 (4))•
COMMERCIAL AVAILABILITY
Nuclear technology is well developed.Nuclear steam supply systems are
commercially available from four different vendors.Due to protracted
licensing and construction requirements,12 years currently are required from
the decision time to bringing a nuclear plant on-line.Therefore,the earliest
on-line date would be 1994,assuming a 1982 decison.
15
~~~."~--~~it"'"
CONVERSION EFFICIENCY
The light water nuclear plants considered here demonstrate a conversion
efficiency of 32.5%and a capacity factor of 65%.
ESTIMATED COST OF POWER
The estimated cost of power from a"1000-MW nuclear plant constructed in
the Railbelt region is 31 mills/kWh.The cost components are as follows:
19
8
4
31
Nuclear Steam-Electric
(mi 11 s/kWh )
Capital
Fuel Cycle
Operating and Maintenance
Total Production Cost
About 60%of the capital expenditures would be outside the Railbelt and most
of the labor would be imported from the lower 48 states.
RESOURCE AVAILABILITY
The available nuclear capacity is essentially unlimited from the
standpoint of resources.By the time U.S.low-cost uranium resources are
exhausted, the fast breeder reactor (FBR),whose costs are insensitive to
uranium supply,is anticipated to be commercially available.
ENVIRONMENTAL CONSEQUENCES
Nuclear plants typically require 250 to 2,000 acres of land for the plant
site and exclusion area.Less than 50 acres of terrestrial biota habitat is
usually lost.As with all large thermal generation plants,significant
quantities of cooling water are required.For a 1000 MWe-plant,310,000 gpm
is needed for a once-through system or 6,200 gpm for a recirculating system.
The withdrawal and discharge of water quantities of this magnitude cause some
impact on aquatic species.Routine radioactive releases present a minimal
16
environmental impact. A major reactor accident that would release enough
radioactivity to contaminate the surrounding area is an extremely small
possibility.This type of accident did not occur, for example,even in the
case of the Three-Mile Island accident.With nuclear plants the radioactive
waste and air pollution problems are minor compared to combustion thermal
plants.
SOCIOECONOMIC CONSIOERATIONS
Construction of a nuclear plant can have adverse affects on nearby small
communities.Housing,public services,and facilities would be potentially
strained.The migration of skilled construction workers and their families
would require an expansion of community services for the 7- to 10-year
construction period.Only within the vicinity of Anchorage could a nuclear
facility be constructed without major socioeconomic impact.Communities of
5000 or less population would experience severe impacts.
17
GEOTHERMAL GENERATION
The design of a geothermal electric plant depends highly on the
characteristics of the particular geothermal resource used.Three basic
generating technologies currently are available:1) dry steam, in which the
geothermal reservoir produces high-quality steam that can be used directly in
turbines;2) flashed steam, in which the hot pressurized water from the
reservoir is flashed to steam for use in turbines;and 3) binary cycle,in
which the low temperature of the geothermal water is used to heat a secondary
working fluid with a low boiling temperature (such as freon or isobutane).
This fluid is used to drive special turbines.Combinations of these basic
designs also have been proposed.The cooled geothermal fluids are generally
reinjected into the underground reservoirs.
Techniques are being developed for extracting energy from IIhot dry rock
ll
geothermal resources.Although this concept shows promise,it is probably 15
to 20 years away from comnerc ta l availability.
POSSIBLE RAILBELT APPLICATIONS
The power plant must be located near the geothermal reservoir.Only hot
dry rock and low-temperature, liquid-dominated hydrothermal resources have
been identified near the Railbelt.Known hydrothermal resources are too low
temperature to be suitable for generation.Hot dry rock technology is as yet
unproven and the resources are remotely located.Because of the presence of
active igneous systems in the Railbelt region,further exploration for
geothermal resources suitable for electrical development appears to be
warranted.
COMMERCIAL AVAILABILITY
The dry-steam and flashed-steam plant technologies are well developed and
commercially available.Both binary cycle and combined-cycle techniques are
currently in the development stage.As just stated,commercial recovery of
energy from hot dry rocks appears to be 15 to 20 years away.
19
CONVERSION EFFICIENCY
A plant operating on dry steam has a conversion efficiency of about 16%.
Depending on the resource temperature,binary cycle designs may operate in a
range of 5 to 10%conversion efficiency.
ESTIMATED COST OF POWER
The cost of geothermal electric energy is highly dependent on the
resource's characteristics.High-temperature dry steam found at shallow
depths can be used to generate electricity at about one fifth the cost of
low-temperature water.The costs for three types of 50-MW geothermal energy
sources operating at 10%conversion efficiency and a 65%capacity factor are
as follows:
Capital
Fuel
Operating and Maintenance
Total Production Cost
Vap or -Domi nated
Hydrothermal
(mi 11 s /kWh 1
9
o
26
35
Binary
Cycle
(mill s /k Wh )
16
o
26
42
Hot Dry Rock
(miUsjkWh)
31
o
26
57
An estimated 55%of the capital expenditures for a geothermal plant would
be spent outside the Railbelt region.About 12%of the operating and
maintenance expenditures would go outside the Railbelt.
RESOURCE AVAILABILITY
Low-temperature liquid-dominated resources have been discovered near
Fairbanks where they have been used for space heating.Exploratory drilling
has located another low-temperatue (170
0F)resource in the Willow area.
Other more remote resources have been located in the Wrangell and Chigmit
Mountains.Currently,geothermal electric generation in the Railbelt seems to
be resource limited.
20
ENVIRONMENTAL CONSEQUENCES
The biggest impact to terrestrial biota from geothermal electric
generation is the effects of drilling numerous production/reinjection wells.
Some loss of habitat from the plant and the reservoir system would occur.If
air emissions (H 2S,radon,methane)are not controlled,they can be
hazardous to both humans and various biota.
Aquatic species can be affected by the accidental release of geothermal
fluids.(Heavy metals and boron are particularly hazardous.) In normal
operation,however,most of the hazardous compounds are reinjected into the
ground.As long as the reinjected material is confined to the geothermal
reservoir,little impact would occur on other water resources.Cooling water
demands per unit of capacity are unusually high for geothermal plants because
of their low conversion efficiencies.
SOCIOECONOMIC CONSIDERATIONS
A 50-MW geothermal electric plant is estimated to require a construction
work force of 90.Because of the remoteness of the areas where the resources
are found,construction camps for the workers probably would be necessary.
21
I•
PEAT-FIRED STEAM-ELECTRIC GENERATION
Peat consists of partially decomposed plant matter and inorganic minerals
that,over time,have accumulated in a water-saturated environment.Peat can
be burned directly to fire a steam-electric plant or can be converted to a gas
for use in a combustion turbine unit.Extensive experience has been gai"ned
using peat burned directly in a steam-electric power plant.
POSSIBLE RAILBELT APPLICATIONS
The Matanuska-Susitna Valley and Kenai Peninsula appear to have peat bogs
that could possibly be suitable for energy production.One site,at Nancy
Lake East, could provide fuel for a 30-MW cogeneration plant for about
15 years.However,significant peat use for power purposes most likely will
not occur in the Railbelt in this decade for two reasons.First,the most
known Alaskan peat has higher than desired ash content.Secondly,more
site-specific resource availability and plant siting information needs to be.
obtai ned.
COMMERCIAL AVAILABILITY
The technology for using peat for a fuel in a steam-electric generating
plant has been well demonstrated.Large plants in the 440-MW to 1000-MW range
are operating or under construction in Ireland,Northern Europe and the Soviet
Union.Little peat has been used in the United States.Boilers ranging from
20 to 300 MW of thermal output to handle peat are commercially available from
European manufacturers.Peat gasifiers are currently under advanced research
and development in the United States and elsewhere.
CONVERSION EFFICIENCY
Peat,because of its inherent high moisture content,introduces thermal
inefficiencies into the combustion process.However,efficiencies improve
with plant size.The heat rate for peat-fired plants of 50 MW is
approximately 14,000 Btu/kWh.This rate compares to a heat rate of about 9000
Btu/kWh for a comparable coal-fired plant.
23
ESTIMATED COST OF POWER
The estimated cost of energy for a peat-fired steam-electric power plant
of 30-MW rated capacity and operating at a 24%conversion efficiency is
79 mills/kWh.The cost components are as follows:
Cap ita1
Fuel
Operating and Maintenance
Total Production Cost
Peat-Based
Steam-Electric (mills/kWh)
11
32
36
79
This estimate compares favorably with a 40-MW peat-fired power plant scheduled
to be built in New Brunswick,where power costs are estimated to be about 55
mills/kWh.
RESOURCE AVAILABILITY
Although the quantity of peat resources is not well defined,significant
fuel peat resources exist.The high ash content of much of Alaska peat could
limit it use,however.Use of peat for power generation will require a
careful matching of peat quality and quantity to power needs on a
site-specific basis.Further resource assessment is necessary before the
potential of peat or a power source alternative in the Railbelt can be fully
evaluated.
ENVIRONMENTAL CONSEQUENCES
The use of peat as an energy resource will impact the region's air,
water,and land resource.A careful matching of power plant location and peat
processing,energy conversion,and emission control methods will be necessary
to minimize environmental impacts.
24
SOCIOECONOMIC CONSIDERATIONS
A construction force of 65 an~an operating staff of up to 25 would be
required for a 15- to 30-MW plant.If the power plant is located at a "bog
site"and construction and operation is associated with bog preparation and
peat harvesting operations,additional staff would be required.Construction
and operation of a facility in a remote location,such as Matanuska-Susitna
Valley,could have significant impact on the small communities (Houston,
Wi llow,and Knick)located nearby.
25
COMBUSTION TURBINES
Combustion turbines can burn natural gas,#2 fuel oil,or coal-derived
fuels.Incoming air is compressed in the first stage of the turbine and fuel
is injected into the combustor stage.The hot gases are expanded through the
power turbine,which drives the compressor and the generator.The hot gases
then are exhausted to the atmosphere.Considerable waste energy in the
exhaust gases can be recovered by using alternative cycles.These cycles will
be discussed under combined-cycle and cogeneration technologies.
POSSIBLE RAIL BELT APPLICATION
Gas turbine plants are commercially available in sizes ranging from
0.5 MW to over 100 MW.Because they require no cooling water,that siting
restriction is removed.If the plants are near a pipeline or refinery,they
are ideally suited to the Railbelt application.Although gas turbines are
designed for peaking operation,they can be used for intermediate or even
baseload operation.Due to their low conversion efficiency,however,they are
not normally used for baseload operation.Regenerative cycles that preheat
the incoming air can enhance combustion turbine efficiency.
Although future installation of oil or gas-fired electrical generating
equipment of over 10-MW capacity is banned by the Fuels Use Act (PIFUA),
Alaska may be able to obtain exemptions because of its unique situation.
Since many of the turbine components are shipped assembled, a plant that burns
gas probably can be on-line 2 years after the decision to build is made •.A
Railbelt plant could be operating by 1984 if a decision were made in 1982.
COMMERCIAL AVAILABILITY
As mentioned earlier,gas turbines are commercially available in a
variety of sizes.
27
28
RESOURCE AVAILABILITY
ESTIMATED COST OF POWER
#2 Fuel
Oi 1
(mi 11 s/kWh)
7
111
7
125
Natural
Gas
(mills/kWh)
7
44
7
58
Cap ita1
Fuel
Operation and Maintenance
Total Production Cost
ENVIRONMENTAL CONSEQUENCES
Because combustion turbines do not require the use of water cooling,
aquatic species should not experience any significant impacts.
Air pollution problems also should be minimal,particularly if natural
gas is used to fire the turbines.Due to the relatively low firing
Although supplies of natural gas and distillates suitable for use in
turbines exist in the Railbelt,their future use is uncertain because of the
present version of the Fuel Use Act.After 1990 the use of natural gas for
electrical generation is prohibited,unless an exception can be obtained.
Combustion turbine plants,however,will be allowed to operate on fuels
derived from coal,biomass products,or distillate oil.
Because most of the plant is preassembled, about 80%of the capital
expenditures would be spent outside the Railbelt.
Depending on size and design,conversion efficiencies of gas turbines
range from 28 to 34%.
Overall power costs from 70-MW gas turbines are estimated at a 65%
capacity factor and a conversion efficiency of 28%.The cost components are
as follows:
CONVERSION EFFICIENCY
Sulphur emissions are no
distillate firing by
temperature,nitrogen oxides are easily controlled.
problem with natural gas; they can be controlled in
controlling the fuel's sulphur content.
Land losses are only 3 acres for a 170-MW plant;therefore,the loss of
habitat should be small.Probably the most serious impact on both terrestrial
biota and humans is the "no ise po l lut ton"caused by turbines.Even with
baffling,these plants tend to give off an offensive high decibel,high pitch
sound.
SOCIOECONOMIC EFFECTS
Because combustion turbine plants can be built with a relatively small
work force,30 construction workers for a 170-MW plant,the socioeconomic
impacts will be minimal.The siting restrictions are few,so construction
near the very small towns that would have difficulty in absorbing even
30 workers should be able to be avoided.
29
COMBINED~CYCLE POWER PLANTS
A combined-cycle power plant uses two thermodynamic cycles to generate
electricity.The prime mover is a combustion turbine that drives a
conventional combustion turbogenerator.The exhaust from the turbine is used
in a heat recovery boiler to generate steam that drives a steam turbine.
Combustion turbines maybe retrofitted to convert them to combined-cycle
generation.Likewise, the steam boilers can be bypassed in a combined cycle
and operate only on the combustion turbine cycle.This mode of operation
allows considerable flexibility both in constructing new capacity and in
operating existing capacity.
The combined-cycle power plant should not be confused with the various
cogeneration designs in which waste heat from the electrical generation is
used for process and/or space heat applications.
POSSIBLE RAILBELT APPLICATIONS
Combined-cycle plants currently are operating in Fairbanks and
Anchorage.Further construction of this type of plant will be restricted by
the Fuel Use Act,which limits the construction of new generating capacity
burning gas or oil after 1990,unless an exemption can be obtained.If coal
gasification plants were built in the Railbelt,then large combined-cycle
plants could be built to operate on the coal-derived gas.The combined-cycle
plants operating on coal-derived gas can operate as intermediate duty or
baseload capacity and would have no restrictions under the Fuel Use Act.
COMMERCIAL AVAILABILITY
Combined-cycle plants currently are available in a wide range of sizes.
Assuming an exemption for a natural-gas-fired design,a 200-MW plant could be
installed in about three years and therefore could be on-line in 1985 with a
1982 decision.Coal gasifier -combined-cycle plants are not yet commercially
available.The earliest such a plant could be on-line in the Railbelt is
estimated to be 1991.
31
CONVERSION EFFICIENCY
The conversion efficiency of a combined-cycle plant is approximately
40%.
ESTIMATED COST OF POWER
The capital costs of combined-cycle plants are markedly higher than the
combustion turbines,but because of higher efficiency,their operating costs
are considerably less.A 200-MW combined-cycle plant operating at a 40%
conversion efficiency and a capacity factor of 15%could generate electricity
in the Railbelt at the estimated costs shown below:
Capital
Fuel
Operation and Maintenance
Total Production Cost
Natural
Gas
(mi 11 s/kWh)
10
33
6
49
#2 Fuel
Oil
(mill s/kWh)
10
79
6
95
Approximately 70%of the capital costs would be spent in the lower 48 states.
ENVIRONMENTAL CONSEQUENCES
Combined-cycle plants are expected to have the same environmental impacts
as those of a combustion turbine.Air emissions would consist of some carbon
monoxide and nitrogen oxides,but ample control technology is available to
keep these emissions within standards.The steam turbine requires cooling
water for the condensers, although much less than a comparably sized plant
operating only on the steam cycle.Loss of habitat will affect terrestrial
biota.About 12 acres of land are needed by a 200-MW plant when fuel storage
is included.
SOCIOECONOMIC CONSIDERATIONS
The construction of a 200-MW combined-cycle plant requires a work force
of 45 for about two years.Severe socioeconomic impacts would be expected
32
only in s~a11 communities where the infrastructure is insufficient to meet new
demands.Because operating and maintenance can be performed with 15 people,
few impacts should result.
33
D1ESEL GENERATION
A diesel generating plant uses an internal combustion engine operating on
a diesel cycle to drive an electric generator.These units are commonly used
for standby or peaking capacity.Some 36 MW of utility capacity and 17 MW of
military capacity presently are installed in the Railbelt.Diesel units are
reliable,with forced outage rates of 10%or less.Also, they can operate
efficiently at less than full load.
POSSIBLE RAILBELT APPLICATION
Diesel generation presently accounts for about 5%of Railbelt
generation.Station sizes typically range from 2 to 18 MW in the Railbelt,
although 30 MW units are available.Few siting constraints exist.Because
cooling systems are usually closed,a constant water supply is not required.
Diesel units require a weatherproof structure that is designed to suppress
noise and also require access to a fuel supply via barge,rail,or truck.
Diesels can start up rapidly under most weather conditions.Thus, they are
useful for emergency power,peaking,and supplemental (to wind or tidal power)
applications.
COMMERCIAL AVAILABILITY
Diesel units are readily available in a wide variety of sizes.Since
they are largely prefabricated,they can be installed in a short time.
Including permits,a 12-MW unit could be on-line in two years or less.
Therefore,a diesel unit could be generating power by 1984 with a 1982
decision.
CONVERSION EFFICIENCY
The conversion efficiency of diesels is sensitive to both design and
size.Typically,diesels in the Railbelt exhibit efficiencies of about 33%.
Very small units have conversion efficiencies as low as 30%,whereas large,
slow-speed units are as'high as 40%.The diesel has excellent load-following
35
characteristics because the efficiency of a 900 kW unit changes only 7.5%over
the entire load range of 400 to 900 kW.A comparable combustion turbine unit
changes more than 100%over the same range.
ESTIMATED COST OF POWER
The estimated costs of power from a 12-MW diesel unit constructed in the
Railbelt and operating at 65%capacity factor and 38%conversion efficiency
are as follows:
Cap ita 1
Fuel
Operation and Maintenance
Total Production Cost
Distillate
Oil
(mi 11 s/kWh)
7
87
6
100
About 80%of the capital c~st of a diesel unit would be spent outside of
Alaska because these units largely are factory assembled and require a minimum
of site labor.
RESOURCE AVAILABILITY
Diesel units can be fueled by a variety of liquid and gaseous
hydrocarbons,but most Alaskan units are presently fueled by distillate oils.
Synthetic fuels,such as 'low and medium Btu gas from coal and biomass,and
methanol, also have been proposed for diesel units.Ample fuel should be
available from one or more of these sources.
ENVIRONMENTAL CONSEQUENCES
Diesel units should cause very small environmental impacts because they
do not require continuous sources of cooling water and because they have a
small land requirement (usually less than 5 acres including tank storage).
Air emissions are mostly carbon monoxide (controlled with catalytic
converters)and particles.Except in the nonattainment areas of Fairbanks and
36
Anchorage,siting approval should not be difficult.Noise pollution is a
problem that can be controlled by noise-suppressing housing for the units.
SOCIOECONOMIC CONSIDERATIONS
Socioeconomic impacts should be minimal because of these units'small
size and because few siting constraints exist.A large diesel generator
(12 MW)would require a construction crew of about 25 workers for a year.
Much of this force could be made up of local laborers,so the impact on even
small communities should be easy to absorb.
37
CONVENTIONAL HYDROELECTRIC
Hydroelectric plants convert the potential and kinetic energy of water
into electrical energy.The two basic types of hydro plants are conventional
and low head.By definition,conventional plants have a head of 20 meters
(65 ft)or more.Conventional hydroelectric plants use a dam to store water
and to establish a hydraulic head, a penstock to convey the water from the
reservoir to the turbines,hydroelectric turbines to generate the electricity,
a tailrace into which the water is discharged after leaving the turbines,and
a spillway over which water not needed for the turbines can be released.Fish
passage equipment may also be required.
Low-head hydroelectric installations have little or no reservoir storage
capacity.They operate essentially as run-of-river generation.They often
use propeller type hydroelectric generators.
POSSIBLE RAILBELT APPLICATION
Over 700 potential hydropower sites have been identified by the Federal
Power Commission,the U.S.Army Corps of Engineers, the U.S.Bureau of
Reclamation,the U.S.Geological Survey,and the State of Alaska.The sites
were assessed based on economic environmental characteristics.The 16 most
promising sites in the Railbelt were selected on this basis.Added to this
list are the two Upper Susitna Sites (Devil Canyon and Watana)plus two other
Railbelt sites (Bradley Lake and Grant Lake),which are being seriously
considered for development.The location of these sites are shown in
Figure 1.The estimated annual energy generation of these 20 dams is over
14,000 GWh,which is greater than five times the current Railbelt energy
demand.Because these sites would be high-head dams with storage capacity,
they are capable of supplying either peaking or baseload capacity.
39
,
PIGURE 1. Candidate Hydroelectric Sites
41::>
IOOMiln50
SCALE
o
40
CANDIDATE
HYDROELECTRIC
SITES
1.SNOW
2.BROWNE
3.CHAKACHAMNA
4.ALLISON
5.WATANA
6.DEVIL CANYON
7.BRANDLEY LAKE
8.STRANDLINE LAKE
-9.KEETNA r
10.GRANT LAKE
11.BRUSKASNA
12.CACHE
13.HICKS
14.JOHNSON
15.LANE \
16.LOWER CHULITNA
17.SILVER LAKE
18.TALKEETNA II
19.TAKACHITNA
20.TUSTUMENA
(I
COMMERCIAL AVAILABILITY
Hydroelectric generation is a well developed technology; the first plant
in the U.S.was put into service in 1882.Two significant hydro plants are
currently operational in the Rai1be1t.One is at Eku1tna (30 MW)near
Anchorage and the other is at Cooper Lake (15 MW)on the Kenai Peninsula.
Solomon Gulch (19 MW)near Valdez is under construction.The type of
conventional hydro plants considered here requires 5 to 10 years to
construct.An estimated 3 to 5 years must be added to construction time for
preconstruction field studies,licensing and design.Therefore,a hydro plant
might be available from 8 to 15 years after a decision to proceed.With a
1982 decision date,a plant could be on-line from 1990 to 1997.
PERFORMANCE
Hydroelectric generators are very efficient -90%or higher.A hydro
plant will characteristically convert to electrical energy 80%or more of the
energy in the water passing through the turbines.A more significant measure
of a hydro project's contribution to a system is the average annual energy
generation divided by the nameplate generator capability (the theoretical
maximum generation).This measure of efficiency (utilization or capacity
factor)takes into account the upstream water storage capacity,the necessity
to spi 11 water during the spring runoff and other factors .that affect the
energy delivered to the system.Hydro projects typically demonstrate a
uti 1ization factor of 45 to 60%.
ESTIMATED COST OF POWER
The cost of power from a hydro project is highly dependent on the
specific site.Major cost variables are type,size head,and location of the
project.An ideal site is located reasonably close to a labor center in a
narrow,deep canyon with a minimum of excavation needed to reach bedrock.
Low-head hydro development requires relatively less expenditure for dams and
spillways than do the conventional high head developments.Estimates have
41
been made of the 20 promising Rai1be1t sites shown in Figure 1.These costs
are shown in the last three columns of Table 2,which summarizes the
characteristics of these sites.An estimated 65%of the costs of a large
hydro project would be spent in the Rai1belt.For a small hydro project,only
about 35%of the expenditures would be made in the Rai1be1t.
ENVIRONMENTAL CONSEQUENCES
The most obvious environmental impact of a hydro project is the loss of
land caused by the impoundment.Conversely,if the river on which the project
is located is subject to flooding,the dam can enhance the usage of downstream
property by controlling the runoff.The reservoir created for a hydro project
causes a fundamental change in the hydrologic system from a flowing-water to a
still-water environment.Evaporation losses and groundwater seepage are then
increased.In the low runoff regions of the northern Rai1be1t,these losses,
if substantial,could cause significant impacts by reducing downstream flow.
The operation of the dam can have adverse ecological impacts.When the
hydro project is used for peaking generation,large diurnal fluctuations in
river flow result.These fluctuations can impact both the aquatic and
terrestrial biota.They can also be hazardous to recreationists.Conversely,
when designed with adequate storage capacity,the dams attenuate flood flow.
They can improve water quality and aquatic habitat by augmenting low river
flow. This flow regulation can be a large positive impact in the Rai1be1t
region where many rivers exhibit wide variations in natural flow.
Water quality is affected by reservoir operation.The large still-water
areas of the reservoir cause stratification during the summer months.Under
these conditions the surface layer is heated to a higher temperature than
would be found under natural free-flowing conditions.Lower layers are not
aerated as much as they would be under free-flow conditions;therefore,a low
dissolved oxygen (DO)content results.Both of these effects (high water
temperature and low DO)can have adverse impacts on aquatic biota,especially
cold water fish.These impacts can be minimized by designing the reservoir
intake structure to take water from several different levels.
42
TABLE 2.Summary of More Favorable Potential Intermediate(a~d Large-
Scale Hydroelectric Sites in the Ra ilbe1t Regi on a
Waterfowl,Est Imated Est Imated Estimated
Raptors Anadr~us Agr Icu Itura 1 Wilderness CuItural,Recreatlona I CapItal Cost(b)O&M cosl Cost of Power
Site ~Game Present Endangered Species Fisher les Potential PotentIal and ScI entl flc ~atures --(S/kW)(S/kw/n:Lc:L -!&!l~
Bradley lake Black Bear PeregrIne FaIcon Hone 25-301 Marginal Soils Good to High Boating 2,900(d)58 49
Grizzly Bear High-Quallty Forests QuaIIty Scenery
Browne Black Bear low Density Hone Hore than 501 Hone Boat Ing Potential 6,245 125 95
Gr III Iy Bear of WaterfowI Marginal Solis
Moose
Caribou (winter)
Bruskasna Black Bear low OensIty of Hone Hone Good to High Boating Potential,Proposed 7,933 160 126
Grizzly Bear Waterfowl,Nest Ing Identified Qua11ty Scenery fco log lea I Reserve
Moose and Holtlng
Caribou (winter)
Cache Black Bear Hone Spawning Hone Good to High Boating Potential 11,275 225 179
Gr III Iy Bea·IdentifIed Area_Identified QuaIlty Scenery
Hoose (wInter)Prl..ltlve lands
Caribou (winter)
Chakachan",a Black Bear Waterfowl Present Spruce and Good to High Quality Boating 2,997 60 4B
Moose Hest Ing and Holt Ing Hardwood Forest Scenery,Prl..ltlve
and Natural Forest
OevII Canyon(f)Black Bear low Popu lat Ion of Spawning Unknown Wilderness Quality Hunting,I,B9O 3B 23(9)
Brown Bear Waterfowl,Cliff Nest-Areas lands Boating
Moose ing Areas for Ravens Oownstream
Car.lbou and Raptors
.j:>o HIcks Black Bear Waterfowl Present Hone Average Qua11ty lluntlng 8,B17 180 141
W Gr III Iy Bear Hestlng and Holtlng Downstream Identified Scenery
CarIbou
Moose (winter)
Johnson Black Bear low Oens tty Waterfowl Spawning 25-501 Suitable Salls Hone Identified BoatIng Hot AvalIab Ie Hot Available 120(e)
Grizzly Bear Nest Ing and Holt Ing Area Spruce-Hardwood
Area Forest
TABLE 2.(contd)
Waterfowl,Est Imated Est Imated Est I,..ted
Raptors AnadrOOIOus Agricultural Wilderness Cultural,Recreational Capital Cosd b)O&M Cost Cost of Energy
Site ._.!!9..Game Present Endangered~~Fisheries Potential Potential and Sc !!..nt1f1~.Fea~r.!tL __t!l~!!l __t$j!!:'/l.'~J.mills/kWIlI _
Keetna Black Bear Hone Spawning Hone Good to High Qualtty High 4,161 95 11
GrIzz Iy Bear Identified Area Identified Pr Imltlve Lands Boat Ing Potent lal
Caribou (winter)
Moose (Fait &Winter)
Lane Black Bear Low DensIty Waterfowl Spawning More than SOli Hone Ident If led
Boating Potential Hot Available Hot Avallab Ie 65(e)
Hoose Hest Ing and Molting Area SuItab Ie Soils
Car Ibou Area Spruce-Poplar Forest
Lower ChuII tna Black Bear Hedlum Oens Ity Water-Spawning More than 5011 Se lected for Wtlder-Boating Potent la I Hot Available Hot Aval lab Ie 59(e)
Grlzz Iy Bear fowl Hestlng and In Vicinity Suitable Solis ness Consideration
Caribou Mo 1tlng Area
Snow BIdck Bear Nest Ing and Mo Itlng Hone Hone Hone Identified Chugach H.F.Proposed 5,092 100 nB
Oall Sheep Area Ident Ifled Blo logical Reserve
Hoose (winter)
Strand Itne Lake Black Bear Hestlng and Molting Hone 25-SOI1 Marginal Soils Good to HIgh QualIty Hone Identified 6,300 130 94
Grizzly Bear Area Scenery,Primitive
Hoose Lands
Talkeetna II Black Bear Hone Spawning Hone Good to High Quamy Boating Potential 9,993 200 15B
Grtzzly Bear Identified Area Identified Scenery,Primitive
Hoose (foil &winter)Lands
Cartbou (winter)
Tokach Itna Black Bea,'Hedlum DensIty Water-Spawning In 5011 of Upland Nearby Prlmlt Ive Boat In9 Potential Hot Avallab Ie Hot Avallab le 64(e)
Hoose fowl Hestlng and Vicinity Soils Sultahle Area~Caribou Molting Area~
lustumena Black Bear Hone Hone None
Selec ted for Wtlder-Hone Identified Not Available.Not Available l25(e)
Dall Sheep
Identified Identified Identified ness Consideration
Good to High Quality
Scenery,Primitive
Lands.Hatural
Features
Watana(f)Black Bear Low Populatlon Spawning Unknown Wtldemess Quality Hunting 3,890 (I)1B (I)SO (n(f)
Brown Bear of Waterfowl Areas lands Boating 4,030 (III BI (III 80 (II )(f)
Moose Downstrea ..
Cartbou
la,Environmental and land-use characteristics and capitol cost est Imates taken from Acres American (198Ib)unless otherwise noted.
b Costs are overnight construction costs In .Iuly 1980 dollars.
c)211 of capital costs used for all projects.
(dl Preferred a lternat tve,Provided In a telephone conversation with John Dennlger from the Alaska Power Administration,Juneau,Alaska.
(e Power costs were determined using cost Indices provided In APA (1980)with Chakachamna estl...te as a base.
(f Devil Canyon and Watana dams comprise the Upper Susltna project,which Is planned to be constructed In three stages,Watana I (680 MY),Watana Ii
(1020 MY),Devil Canyon \600 141).Average cost of power following construction of all stages Is 56 mills/kWh.
(9) Corps of Engineers (1980 .
As water is spilled over the spillway (typically during the spring
runoff),it entrains atmospheric gases (nitrogen and oxygen).When the gas
levels reach the supersaturation point,they can cause death to fish.
Similarly,the high velocity of water in the spillways and outlet structures
can cause scouring of the dam structures and river banks.Both of these
effects can be mitigated by proper spillway design.
Alteration of streamflow characteristics by hydroelectric projects can
have a serious impact on aquatic biota.Of particular concern in the Railbelt
region is the effect on the anadromous salmonids.Major impacts that are
difficult to mitigate include the following:loss of spawning areas above and
below the dam;loss of rearing habitat;reduction or elimination of upstream
access to mitigating fish;increased mortalities of downstream migrants;and
altered timing of downstream migration.An initial assessment of potential
hydropower sites in Alaska indicates that major impacts on anadromous fish
could be expected on such salmon streams as the Tanana,Beluga,Skwentna,
Susitna,and Copper Rive~s.
The major impact on terrestial biota is the inundation of large land
areas of wildlife habitat.Big game animals can be affected by loss of
seasonal ranges and interrupt~on of migratory routes.Winter ranges are
particularly critical.Flood control by dams may significantly reduce the
extent of wetland habitats because of the elimination of seasonal inundation
of large areas downstream of the dams.This action can be expected to
adversely affect moose and other wetland species.Fish-eating raptors and
bears could be affected by the loss of andromous fish if passage is reduced or
eliminated by the dams.
Mitigative measures can be taken to reduce many of these impacts, except
the loss of habitat.However,some new habitat,such as nesting islands,
could be created by spoils or channels.Impacts on wildlife can be minimized
by selecting only those sites where wildlife disturbances would be the least.
Table 1 summarizes the environmental impacts that could be anticipated at the
20 most promising Railbelt hydro sites.
45
SOCIOECONOMIC CONSIDERATIONS
The combination of remote sites and a large number of construction
workers can be expected to cause a boom/bust cycle for most conventional hydro
projects in the Railbelt.These sites are located at or near communities with
a population of 500 or less.The in-migration of the 250 to 100 workers
required for a project in the range of 100 to 1000 MW would more than
quadruple the present population.Table 3 shows the representative labor
forces and construction periods for small and medium-sized projects.The
installation of a construction camp would not mitigate the impacts on the
social and economic structure of a community.
TABLE 3.Representative Manning Requirements for Hydroelectric Projects
j
I.~
Rated Capacity
Small Hydro (5 MW)
Conventional Hydro
(100 MW)
(a)To first power.
Construction
Period
(years)la)
2
5 to 10
Construction Personnel
(number of persons)
25 to 35
200 to 400
46
Operation Personnel
(number of persons)
2 to 3
10 to 12
FUEL CELLS
The fuel cell is a solid state device for producing electricity by
electrochemically combining hydrogen and oxygen.The hydrogen is supplied by
reforming a hydrocarbon fuel such as oil,natural gas,or low or medium Btu
synthetic gas derived from coal or other biomass sources.The oxygen is
obtained from the atmosphere.Two basic fuel cell designs are currently under
development:a cell using phosphoric acid as an electrolyte and a more
advanced cell using molten carbonate as an electrolyte.Current demonstration
fuel cell plants range in size from 25 kW to 11 MW.
POSSIBLE RAILBELT APPLICATION
When commercially available,fuel cell power plants could potentially
playa useful role in the Railbelt electric power system as peak power
generating units.The superior heat rate of fuel cell power plants over
traditional natural gas combustion turbines peaking units is largely
responsible for this potential.In the Anchorage area,fuel cell stations in
the 10- to 25-MW size range fueled by natural gas could serve in a peaking and
intermediate load-following capacity.Similar-sized fuel cell units could be
an appealing follow-on system to existing combustion turbine power plants in
the Fairbanks area.Coal gasifier or natural gas fired - fuel cell -combined
cycle plants also hold future promise in a baseload capacity role.
COMMERCIAL AVAILABILITY
Fuel cells are an emerging technology.No commercial units are currently
operating,although several demonstration units in the commercial size range
are currently being tested.Most demonstration plant experience has been
achieved using phosphoric acid as the electrolyte.Several small plants (1 MW
or less)using the phosphoric acid'fuel cells have demonstrated satisfactory
operation.Units incorporating this technology are expected to be
commercially available in the mid 1980s.Fuel cell power stations
incorporating molten carbonate electrolytes and combined-cycle technology are
not expected to be commercially available until the late 1980s and early
47
1990s. Early introduction of fuel cell power plants could be con~trained by
technical problems,insufficient orders,and national fuel policy.
CONVERSION EFFICIENCY
Fuel cell efficiencies are typically better than conventional methods of
converting thermal energy to mechanical energy for power generation.
Stand-alone fuel cell stations should exhibit conversion efficiencies in the
range of 38 to 47%.If fuel cell stations are operated in the combined-cycle
mode,efficiencies should range from 48 to 60%.
ESTIMATED COST OF POWER
The estimated costs of power from dispersed fuel cell stations using
phosphoric acid electrolyte and operating at a 38%conversion efficiency are
est imated as fo 11 ows:
Cap ita 1
Fuel
Operation and Maintenance
Total Production Cost
Dist ill ate
(mi 11 s/kWh)
9
81
7
97
Natural Gas
(mi 11 s/kWh)
9
32
8
49
These costs are for 10-MW units operating at a 65%capacity factor located in
an urban area.Only rough estimates of coal gasifier and natural gas
combined-cycle plants are available.Power costs for these plants are
expected to be 45 and 31 mills/kWh,respectively.
RESOURCE AVAILABILITY
Fuel cells can be fueled by a variety of liquid and gaseous hydrocarbons.
Synthetic fuels,such as low and medium Btu gas from coal and biomass,are
also being evaluated.The most fully developed process uses naphtha and
methane in phosphoric acid fuel cells.If current availability of
competitively priced natural gas in the Railbelt region continues,fuel cell
stations could serve well as peaking and intermediate load-following units.
48
In the 1990s coal deposits in the Railbelt area (e.g.,Beluga,Nenana)could
provide the fuel for gasifier -combined cycle - fuel cell plants operated as
baseload stations.
ENVIRONMENTAL CONSEQUENCES
Fuel cell plants are not expected to have major environmental impacts.
Because of the high efficiencies of fuel cells and ease of controlling
potential pollutants,fuel cells represent a dramatic improvement in
air-quality impacts over combustion technologies.Water is produced by fuel
cells during normal operation,minimizing the need for water during
operation.Additional cooling water may be required by fuel cells operated as
combined-cycle plants,however.Appropriate water-wastewater management
planning will assure that thermal discharges comply with receiving stream
standards.Impact on the terrestrial ecosystem is expected controlled to
acceptable levels by proper siting.
SOCIOECONOMIC CONSIDERATIONS
Because of the availability of fuel and the absence of major
environmental effects,small-scale (10 MW)fuel cell plants would be located
in or near load centers to minimize transmission losses.Construction of
these plants would extend over a year and would involve a work force of
90 persons. A construction force of this size could have a significant impact
on a small community but little on a large community.Construction of a
larger combined-cycle fuel cell plant could have a relatively greater impact.
49
STORAGE TECHNOLOGIES
Energy-storage technologies provide a way to use baseload electrical
generating capacity to meet peak power demands.Energy-storage technologies
have three major applications:1)storage of energy from baseload plants
during off-peak hours for release during peak periods,2)storage of energy
from intermittent operating generating facilities,and 3) standby power supply
in case of power station or transmission system failure.
PUMPED HYDROELECTRIC
A hydroelectric pumped-storage plant consists of an upper and a lower
reservoir,a reversing turbogenerator,and interconnecting piping.Water is
pumped from a lower reservoir to the upper reservoir during off-peak hours.
During peak demand periods,the water is allowed to flow from the upper
reservoir through turbines to the lower reservoir,generating power in the
process.
Possible Railbelt Applications
No hydroelectric pumped-storage projects have been developed in the
Railbelt region.Circumstances under which development of pumped storage and
other energy-storage projects might be attractive in the Railbelt region
include the following:
1.use of energy-storage projects in conjunction with natural-gas-fired
combined-cycle baseload plants to meet peak loads
2.use of energy-storage projects in conjunction with coal-fired
baseload plants to meet peak loads
3.use of energy-storage projects to retime output of the proposed Cook
Inlet tidal power project
4.use of energy-storage projects in conjunction with dispersed
smaller-scale intermittent power projects (solar or wind)to provide
firm power
5.use of energy-storage projects to enhance system reliability.
51
Commercial Availability
,Hydroelectric pumped-storage is a well-developed technology.
Pumped-storage plants had their commercial origin in the United States in
1929.Commercially operating pumps/turbines have been built with capacities
ranging from 1.5 to 400 MW,with larger units expected in the future.
Conversion Efficiency
The overall conversion efficiency of hydroelectric pumped-storage plants
is about 72%.
Estimated Cost of Power
Estimated costs for pumped-storage installations are highly site
specific.Costs can vary significantly.Electric energy costs with 20-mill
baseload power is estimated to be 56 mills/kWh for a 100-MW plant facility
operating at a 21%capacity factor.The cost components are as follows:
Cap ita1
Fuel
Operation and Maintenance
Total Production Cost
Pumped Storage
(mi 11 s/kWh)
23
28 .
5
56
Resource Availability
Although pumped-storage sites have not been identified in the Railbelt
region, the significant hydro potential in the region indicates that such
future development is possible as fossil fuel availability,load,and
alternative energy generating conditions permit.
Environmental Consequences
The impacts of a hydroelectric pumped-storage facility on water resources
are significant and are similar to those of a conventional hydroelectric
facility.The major impacts occur from basin flooding and alteration of the
natural hydraulic regime of both surface water and groundwater.Biological
impacts are also potentially significant and will require detailed evaluation
52
to assure minimum impact.The impacts on the terrestrial ecology are
primarily loss of natural habitat and wildlife disturbance from potential
increased human intrusion.Overall,the environmental impact of
pumped-storage facilities will be a major consideration in plant siting,and
to a degree, in operations.
Socioeconomic Considerations
Construction of a pumped-storage plant is labor intensive,involving as
many as 350 workers for a 100-MW plant and a construction period of 4 to
5 years.The impact from construction of a 100-MW plant would range from
minimal to major,depending on site selection.
STORAGE BATTERIES
In periods of low demand,electricity can be converted from high-voltage
AC into lower voltage DC and stored in batteries.During peak load periods
the process can be reversed to carry part of the utility's load.
Possible Railbelt Application
Circumstances under wh ich development of storage batteries mi ght be
attractive in the Railbelt region are the same as those listed under "Possible
Railbelt Applications"for hydroelectric pumped storage.
Commercial Availability
Utility-scale use of storage batteries is an emerging technology.
Development of advanced batteries systems specifically designed for
load-leveling applications is under way at several companies.
Commercial-scale systems are expected to become available for utility use in
the 1988-1992 time period.Thus,any Railbelt application will be in the
midterm to long term.
Performance
Station-equivalent annual availability is estimated to exceed 90%.A
30-year economic lifetime with several replacements of batteries is estimated.
53
Estimated Cost of Power
The incremental power costs for a variety of advanced storage batteries
for 20-, 40-,and 80-mill baseload power costs are estimated to range between
38 and 130 mills/kWh.These are tentative costs because actual manufacturing,
O&M costs and lifetimes are only rough estimates.
Environmental Considerations
Advanced battery facilities are designed to have minimum impact on their
surroundings.Land area required for a 100-MW station would be only about
one-half acre.
Socioeconomic Effects
The maximum construction force for a battery-storage faCility would be 20
to 40 persons.Because a battery power would logically be located near a load
center,the impact of construction would be small.Out-of-state capital
spending is estimated to be 85%.
COMPRESSED AIR ENERGY STORAGE (CAES)
In compressed air energy storage during off-peak hours,surplus energy
from a utility grid is used to compress air for storage underground in manmade
or natural geologic structures.During peak-demand periods,the air is
released from the storage area,reheated and then expanded in turbines to
generate electricity.
Possible Railbelt Applications
Presently,the Railbelt region does not have a suitable baseload
generating capacity to warrant consideration of CAES.Circumstances under
which use of CAES systems may become feasible in the Railbelt region are the
same as those listed under "Possible Railbelt Applications"hydroelectric
pumped storage.(CAES would be less suited for dispersed system backup
capacity.)
Commercial Availability
The first (and only)CAES plant started operation in West Germany in
1978.Operating results on this 290-MW facility have been excellent.In the
54
United States,several sites have been evaluated for possible CAES
facilities.Although the cost effectiveness of these conceptual plants
generally has been confirmed,no decision has been made to build a plant.
Performance
The electrical input/output ratio of a conventional (reheat)CAES plant
is about 0.75:1.0.
Estimated Cost of Power
For 924-MW rated capacity hard rock CAES plant,the estimated incremental
electric energy cost will be 54 mills/kWh.This cost assumes a 1990 startup
date,30-year economic life,Cook Inlet Natural Gas for reheat and a
20-mill/kWh baseload cost.The estimated cost components are as follows:
Compressed Air Storage
(mills/kWh)
Capital
Fuel
Operation and Maintenance
Total Production Cost
21
27
6
54
Resource Availability
Siting a CAES plant is a major task.Finding a suitable geologic
structure requires the most effort.A variety of competitively priced fossil
fuel resources are available in the Railbelt region to meet CAES reheat
needs.However,before a CAES plant can be constructed,the baseload
generating capacity in the region must be expanded and the CAES options must
be reviewed in detail.
Environmental Consequences
The environmental impacts of a CAES plant depend upon the type of storage
medium employed •.The most serious impacts may result from the construction
activities themselves.The excavated material from salt domes and hard rock
cavern systems pose significant storage/disposal problems. Aquifer CAES
systems'impact on groundwater quality will also have to be carefully
55
assessed.Standard air-quality control measures will have to be incorporated
to minimize impact from the fossil-fuel-fired reheat facility.
Socioeconomic Consequences
Construction of a large CAES plant is labor intensive.A construction
force of 150 to 300 would be required over a five-year period.Significant
impacts can be expected on small communities located near the construction.
The operating staff for a CAES facility is very small and should not impact
local communities.
56
COGENERATION
Cogeneration is the sumultaneous production of electricity and useful
heat.The heat,in the form of steam or hot water,may be distributed to
commerci~l or residential users in district heating systems or to industrial
users for process heat applications.
Cogeneration systems can be classified into two thermodynamics cycles:
• topping cycle - High-temperature steam, gas or diesel power is used
to generate electricity and the rejected energy is used for process
heat or space heating.
•bottoming cycle - High-temperature steam is used for process heat
and the rejected steam is used in a special saturated steam turbine
to generate electricity.
POSSIBLERAILBELT APPLICATIONS
Significant potential for cogeneration exists in the Railbelt.Because
cogeneration must be located adjacent to industrial or large residential
users,the refineries on the Kenai peninsula,and Fairbanks have the greatest
potential.Other petroleum-related activities such as oil and gas pumping
stations also have potential applications.If natural gas liquefaction (LNG)
facilities are installed,they would have a high potential.Other industrial
and military installations could use cogeneration designs.Hospitals,large
apartment complexes and other institutions in the high population areas of the
Railbelt also are potential users.
COMMERCIAL AVAILABILITY
A variety of cogeneration designs are commercially available.The time
required to license and install a plant may be dictated more by process heat
use than by the electrical generation.The possible combinations of prime
energy source and process heat use are so numerous that estimating a date by
which this type of capacity could be on-line would be difficult,but a range
of 2 to 6 years after the date of decision p,robably would cover most
applications.
57
CONVERSION EFFICIENCY
The best measure of the efficiency of cogeneration should be percent of
heat use.The electrical generation part of the cycle will convert the
thermal energy of the primary heat source to electrical energy at an
efficiency that is characteristic of the particular generation design (steam,
gas turbine,or diesel).In addition,the waste or reject heat will be
further used.The overall efficiency is usually in the range of 65 to 85%.
COST OF POWER
The cost of power from cogeneration is hard to define precisely.For
example,if a refinery generates surplus electricity,which it supplies to the
grid,the value of that power is the price the utility will pay for it.
Alternatively,the power costs can be calculated by assigning a value to the
process heat and deriving power costs as a by-product.An estimated 60 to 70%
of the capital expenses of such installations would be spent outside the
Railbelt.
ENVIRONMENTAL CONSEQUENCES
A cogeneration facility should have the same environmental impact as a
simple generating station of the same capacity and type. For example,a 12-MW
diesel cogeneration facility would be expected to discharge the same air
emissions as would a comparable diesel generating station.The land-use
factor would be higher in cogeneration if the acreage used by the process heat
part of the facility is included.
SOCIOECONOMIC CONSIDERATIONS
Work forces may vary from 25 to 250 for the construction of cogeneration
plants.Since the plants would probably be built in large industrial zones,
little socioeconomic impact should occur.
58
TIDAL POWER
Tidal power uses the ebb and flow of tidal movement in an estuary to
drive turbogenerators.The estuary is dammed to convert the potential energy
from this movement to electricity.Because the available head is limited by
the tidal rise,the turbines are of a special low-head design.The design of
the dam and associated equipment is specific to the site.Only two tidal
facilities are operating in the world.One is the Rance Project (240 MW)in
northwest France and the other is the Kislogubsk station (0.4 MW)on Kislaya
Bay,USSR.
POSSIBLE RAILBELT APPLICATION
Tidal power is intermittent;the tidal cycle goes from peak to peak every
12.9 hours. Unless some auxiliary pumped-storage capacity is added, a tidal
power facilit~is capable of generating electricity less than 12 hours per day.
Cook Inlet is one of the few sites in the world with a significant tidal
power potential.Estimates indicate that up to 2600 MW may be available on
the Knik and Turnagain Arms of Cook Inlet.Although tides are regular and
predictable,the timing constantly changes.Therefore,tidal facilities
deliver peak power approximately twice a day but at differing times.Peak
generating capacity also changes with the seasonal tides.Because tidal power
is intermittent,it is useful primarily as a supplementary source of energy
unless storage capacity is provided to allow consistent energy production.In
short,tidal power is a renewable source of energy, but without storage it
presents unique system problems.
COMMERCIAL AVAILABILITY
The material,design and equipment required to construct a tidal power
plant are currently available.Plants have been constructed in France and the
Soviet Union and are currently in the planning stage in eastern Canada.A
Cook Inlet tidal plant would require a lengthy construction period,from 15 to
20 years.Railbelt system demand would have to grow considerably before
59
it could accommodate an intermittent source of power in the 700 to 1500 MW
range that is characteristic of the Cook Inlet.Based on system
considerations,the Railbelt would not be able to accommodate such a facility
before 2000 and possibly not before 2025.
PERFORMANCE
A tidal power facility converts the potential energy of the rising and
falling tides into electrical energy.Although hydrogenerators are very
efficient,the change in generating efficiency as the head drops and the down
time while the reservoir is filling must be considered.One measure of design
efficiency is to compare the electrical energy actually generated in a year to
the energy that would be converted if all generators were to operate at full
capacity the entire year.Preliminary analyses show that from 32 to 36%of
the nameplate generation (theoretical maximum output)will be realized.
ESTIMATED COST OF POWER
A rough estimated power cost from a tidal station on Cook Inlet ranges
from 46 to 129 mills/kWh depending on the site chosen and assumptions made on
the disposition of off-peak power.
ENVIRONMENTAL CONSEQUENCES
The largest effects of a tidal power plant probably would be felt by the
marine ecology. Short-term impacts would arise from dredging some 30 million
cubic yards of sediments to prepare the foundation.About 7 million cubic
yards of fill rock would be needed.Long-term effects could be expected from
the change in water circulation patterns and the movement of glacial sediments
deposited during the summer runoff.Anadromous fish migrations would be
affected,as would the smelt runs.
The terrestrial ecology would be affected by the construction of access
roads,by the dumping of dredge materials,and by the acquisition of fill.
60
SOC IOECONOMIC CONSIDERATIONS
A tidal power station of the 700 to 1500 MW size envisioned for Cook
Inlet would require 2000 to 3000 construction workers for a 7- to 12-year
period.Most of this labor force would be based in Anchorage.This size
labor force could put a severe strain on housing and community infrastructure
if employment were already high at the time of peak construction.
61
LARGE WIND ENERGY SYSTEMS
Wind energy is converted into electrical energy in two steps.In the
first step the kinetic energy of the wind is converted into rotational energy
of the blades.In the second step,the rotational energy of the blades is
used to drive an electrical generator.Small wind energy devices have been
used for many years,but 1arge systems (over 0.1 MW capacity)are sti 11 in the
developmental stage.
Three basic configurations of wind machines exist.They are classified
according to the axis of rotation relative to wind direction as horizontal
axis,vertical axis,or cross-wind horizontal axis.Vertical axis machines
are generally less efficient than horizontal axis ones, but because they do
not require a tower, they have a lower capital cost.They have the added
advantage of being insensitive to wind direction.Cross-wind horizontal axis
machines do not represent an improvement over either of the other two types.
At the current stage of development,horizontal axis designs probably will be
preferred for megawatt-scale machines.
POSSIBLE RAILBELT APPLICATIONS
Wind energy conversion units from 0.1-to 5-MW capacity would be well
suited to the Railbelt.The power generated is,however,intermittent and
requires backup capacity.Isolated communities that have diesel or gas
turbine generation might profit from supplementary wind power.In combination
with a hydro or pumped-storage system, a wind energy farm could make a
significant energy contribution because it could store energy.
COMMERCIAL AVAILABILITY
Large wind turbines in the range of 1 to 2.5 MW are commercially
available.A MOD-1 turbine (2 MW)has operated at Boone,North Carolina,
since 1979. Three MOD-2 (2.5 MW apiece)turbines went into operation in 1981
near Goldendale,Washington.These and other wind turbines are available,but
the benefits of assembly line production have not yet been realized.
63
PERFORMANCE
Capacity factor is typically used as a measure of a wind turbine's
efficiency.Capacity factor is the actual power generated in a year divided
by the theoretical maximum that would be generated if the wind were to blow at
the optimum speed all year long. Since the output of a wind turbine is
sensitive to both the velocity and steadiness of the wind, the capacity factor
is highly site dependent.For a good site a capacity factor of 30 to 40%can
be expected.
ESTIMATED COST OF POWER
64
ENVIRONMENTAL CONSEQUENCES
The estimated costs of power from a 2.5-MW wind turbine installed in the
Rai1be1t are as follows:
Large Wind Systems
With 30%Capac tty
Factor (mills/kWh)
65
o
7
72
Large Wind Systems
With 40%Capacity
Factor (mills/kWh)
49
o
5
54
Capital
Fuel
Operation and Maintenance
Total Production Cost
Approximately 80%of the capital cost of a wind turbine installation would be
spent outside Alaska.
Since wind turbines extract energy from the atmosphere, they can be
expected to have a small impact on the climate in the immediate vicinity.The
affected zone would be limited to a distance equivalent to 5 rotor diameters,
which is 1500 feet for a MOD-2 turbine.
Rotation of the turbine blades can interfere with television,radio,and
microwave transmission.Low-frequency sound also has been detected downwind
of some installations.This impact is potentially stressful on human and
animal populations.
For maximum efficiency,a smooth,flat site is desirable.Any trees or
shrubs that cause air turbulence may have to be removed.The large land areas
required (particularly for mu1titurbine wind farms)could affect terrestrial
biota through loss of habitat.
Shoreline development could affect both harbor seals and migratory
birds.The effect of such installations on harbor seals,which use much of
the coastline,is unknown.If the turbines are located in the flyways of
migrating waterfowl, bald eagles,peregrine falcons,or other birds,
collisions with the rotating blades would be possible.
SOCIOECONOMIC CONSIDERATIONS
Erection of a 1- to 2-MW wind turbine would require approximately 2 years
for site selection,including time to procure fabricated components,and about
6 months for construction.A crew of 10 to 15 would be required during
construction,but no permanent onsite operating force would be needed.
Because of the small size of the construction force,the socioeconomic impacts
on even the smallest community should be minimal.
The construction of a 100-MWwind farm is expected to require a work
force of about 60 over a 2-year period.This size labor force could cause
some strain on small communities.
65
SMALL WIND ENERGY SYSTEMS
Small wind energy conversion systems (SWECS)are wind turbines with rated
capacities of 100 kW or less.Both horizontal and vertical axis machines
exist.The horizontal machines have a higher efficiency but require a tower,
which adds to capital costs.The vertical axis machines have the advantage of
not being sensitive to wind direction •.Machines may be equipped with either
alternating current (AC)or direct current (DC)generators.Alternating
current generators will allow the power from the turbines to be used at the
installation or to feed a utility grid.Direct current generators are usually
used to recharge at offgrid installations where batteries are provided for
backup power during calm periods.
POSSIBLE RAILBELT APPLICATION
The small capacity of SWECS installations makes system additions
convenient.SWECS is,however,an intermittent energy source.Unless it is
used in conjunction with a hydro,pumped storage,or some other storage,it
can be regarded only as a fuel saver.
Some Railbelt sites may have the necessary wind conditions to use SWECS.
Macro wind energy surveys,however,indicate that the most promising areas are
outside Railbelt population centers.It thus appears that SWECS have only a
limited potential in the Railbelt.
COMMERCIAL AVAILABILITY
Currently,small wind turbines are available from over 50 manufacturers.
A Railbelt dealership and a repair network is already in place.
CONVERSION EFFICIENCY
The electrical generation that can actually be realized over a year's
time is of primary interest in evaluating a SWECS.That figure is a function
67
68
ESTIMATED COST OF POWER
ENVIRONMENTAL CONSEQUENCES
SWECS
0.002 MW
(mi 11s/kWh)
50
o
7
57
SWECS
0.01 MW
(mi 11 s/kWh)
40
o
6
46
Cap ita1
Fuel
Operation and Maintenance
Total Production Cost
The estimated cost of power from a SWECS installed in the Railbelt
operating a 40%capacity factor are shown below.These costs are somewhat
sensitive to the size of the installation.
of the wind turbine design,the installation site,and the equipment's
reliability.If the SWECS electrical generation over a year is divided by the
theoretical maximum output (the nameplate rating)the capacity factor ranges
from 25 to 40%.
If the SWECS were manufactured in the Railbelt,essentially all of the capital
costs would be expended in the Railbelt.Almost all the O&M expenditures
would be spent in the Railbelt.
A potential hazard to low flying migratory birds could result from a
SWECS,although this possibility is not considered serious.A compensating
wildlife enhancement can be expected due to downwind sheltering from the
turbines.Noise is not a problem with SWECS.Radio and microwave
interference can be mitigated by proper blade design and the use of
nonmetallic materials.
SOCIOECONOMIC CONSIDERATIONS
Land use in the cities would present significant problems for SWECS
because of safety and building code considerations.In the rural areas,which
make up most of the Railbelt,these factors would not be expected to weigh
very heavily.
Typically,a two-to four-man crew can complete a SWECS installation in a
few weeks.No construction socioeconomic impacts should occur in even the
smallest community.Operation and maintenance also present no problems.
69
SOLAR ELECTRIC·POWER
Two basic methods for generating electric power from solar radiation are
under development:solar thermal conversion and photovoltaic systems. Solar
thermal systems convert solar energy to heat via a working fluid such as
water t steam t air t various solutions and molten metals.Energy is extracted
from this working fluid to drive a turbine.In photovoltaic systemst solar
energy is converted into electric energy in a photo sensitive substance.
POSSIBLE RAILBELT APPLICATIONS
The lack of winter sunshine in the Railbelt clearly limits solar energy
as an alternative for electric power generation.Solar radiation data
collected at Fairbanks and near Anchorage revealed-that mid-winter values were
a maximum of only 48 Btu/ft2 in December and 1 t969 Btu/ft 2 in June. This
compares with Minnesota (a relatively poor site)where the year-around range
is 550 Btu/ft 2 to 2tOOO Btu/ft 2•
COr+1ERCIAL AVAILABILITY
Photovoltaic cells are commercially available from several firms.The
cells are assembled in modular units of varying voltages and current outputs.
Solar thermal feasibility is currently being evaluated in test and
demonstration facilities in Albuquerque t New Mexico t and Barstow t California.
CONVERSION EFFICIENCIES'"
Photovoltaic system conversion efficiencies currently range from
approximately 2 to 13%.Advanced concepts point to efficiencies approaching
40%.Conversion efficiencies for a power tower solar thermal system range
from 10 to 70%t depending on climatic conditions.
ESTIMATED COST OF POWER
The estimated power cost for a 10-MW photovoltaic power plant operating
at a 15%conversion efficiency is 620 mills/kWh.A comparably sized solar
71
thermal system also operating at Q 15%conversion efficiency could expect to
generate electricity at 92 mills/kWh.The cost components are presented below:
Capital
Fuel
Operating and Maintenance
Total Production Costs
RESOURCE AVAILABILITY
Photovo1taic (10 MW)
(mills/kWh)
593
o
27
620
Solar Thermal (10 MW)
(mills/kWh)
65
o
27
92
Low sun angles,characteristic of Alaskan latitudes,provide less solar
radiation per unit area of the earth's surface than in other areas of the
country.This creates the requirement for greater collector areas to achieve
a given rated capacity.Increasing the "t i l t "of collectors increases solar
power densities but shades,adjacent collection devices at low sun angles.
These factors,plus low solar radiation availability during the months of
greatest demand,severely constrains solar ~nergy development in the Rai1be1t
region.
ENVIRONMENTAL CONSEQUENCES
Air-quality impacts for photovo1taic and solar thermal systems are
expected to be minimal.Water resource effects are also not expected to be
significant for photovo1taic systems. Solar thermal conversion systems would
produce water resource effects similar to those of other steam-cycle
facilities.Many of the working fluids being proposed for solar thermal
systems will require special handling to avoid undesirable ecological
effects.Because of the land-intensive characteristic of solar systems, a
significant environmental effect could be the loss of habitat.
SOCIOECONOMIC CONSIDERATIONS
Both solar photovo1taic and solar thermal systems require a relatively
large constructi.on force but a small operating staff.A lO-MW photovo1taic
72
J
plant would require a construction force of about 100 and an operati-ng staff
of 10.Little socioeconomic impact could be expected if a solar plant were
located near a major load center.
73
SMALL HYDROELECTRIC AND MICROHYDROELECTRIC POWER
Small-scale hydroelectric plants are facilities having installed
capacities of 100 kW to 15,000 kW.Units with 100 kW or less of capacity are
classed as microhydroelectric units.Small-scale hydroelectric and
microhydroelectric power plants are similar in principle to conventional
hydroelectric facilities but differ from these installations in several
important ways.First,the small-scale hydroelectric and microhydroelectric
units usually operate with a hydraulic head of 100 ft or less.They are also
typically single-purpose (power only)facilities.Finally,they operate as
run-of-the-river units,having no working storage.While small hydro power
facilities may be the most economically feasible alternative to meet a
particular power need, the above characteristics can lead to relatively high
per-kilowatt capital costs.
POSSIBLE RAILBELT APPLICATIONS
Although 16 small-scale hydro·power plants are currently operating in
Alaska, only one, the 15-MW Cooper Lake project on the Kenai Peninsula,is
operating within the Railbelt region.Feasibility studies have been completed
on potential small-scale hydro projects at Grant Lake,near Seward,and
Allison Creek,near Valdez. Thirteen additional technically feasible small
hydro sites have been identified.The potential for microhydro development in
the Railbelt region is estimted to be 9 MW in generating capacity.Most of
these sites could be expected to be developed in the Anchorage load center
area.
COMMERCIAL AVAILABILITY
Packaged turbo-generator units for small-scale and microhydroelectric
power plants are available from many domestic and foreign manufacturers.
CONVERSION EFFICIENCY
Efficiencies for hydroelectric facilities range from 50 to 85%,depending
on the type of equipment used and scale of operation.As flow rate and/or
75
off from a maximum of 90%at
Microhydro system
Grid-connected microhydro
savers at a 60 to 100%plant
head vary, the efficiency of the turbine can drop
100%capacity to about 75%at 20%rated capacity.
efficiencies generally range between 50 and 70%.
and small-scale hydro units are operated as fuel
capacity factor.
ESTIMATED COST OF POWER
The estimated cost of power for grid-connected small hydro and microhydro
plants ranges widely from 14 to 254 mills/kWh for local,and from 111 to 343
mills/kWh for remote facilities.The broad cost difference is the result of
major costs of access roads and transmission systems.The broad range within
each category is largely the result of varying system operating conditions and
equipment types used in these installations.An estimated 60%of the capital
expenditures can be expected to be spent outside of the Railbelt area.
ENVIRONMENTAL CONSEQUENCES
Special consideration will have to be given to mitigating potential
problems with the passage of anadromous fish.The presence of power
transmission and access road corridors through the forest could potentially
disrupt wildlife migration patterns.The aesthetic aspects may become
significant if numerous microhydro and small hydro plants were developed
within a limited area.Because of the relatively small plant capacities
involved and limited number of feasible sites,impacts should be minimized
through careful site selection.
SOCIOECONOMIC CONSIDERATIONS
Socioeconomic impacts should be minor to modest,as a relatively small
labor force for construction and operation will be required.The construction
force for a small-scale plant could range up to 20 individuals for a 12- to
24-month period.Small towns with undeveloped infrastructure could experience
some detrimental impact.
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LOAD MANAGEMENT
Load management is any action taken by a utility to directly affect
customer loads or to influence customers to alter their electrical use
characteristics.The objective of load management is to shift,shed, or shave
peak loads to derive a more economical load profile.
POSSIBLE RAILBELT APPLICATION
The Railbelt utilities are currently employing load management
alternatives.However,opportunities for additional load management in the
Railbelt region appear to be limited,mainly because few loads are
controllable.If low-cost power becomes widely available in the future,with
resulting increased space and water heating electrical loads,aggressive load
management programs may become desirable.
COMMERCIAL AVAILABILITY
Load management techniques were first used in Europe.Recently, in the
United States,many load management programs have been implemented or are
under development.Although many of these programs have proved to be cost
effective,they are generally still in the experimental or demonstration
phases.
Examples of load management methods include direct load control,passive
controls,incentive pricing,education and public involvement,and dispersed
thermal energy storage.
1. Direct load control is the control of specific customer loads by the
utility.Residential loads for water heating can be controlled
directly but can cause customer inconvenience or discomfort.The
use of clothes dryers can often be shifted to off-peak hours.
Direct control devices include clock timer switches,temperature
sensing controllers,and photo controllers.Control can also be
obtained remotely using the existing transmission and distribution
system to transmit a signal.
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2. Passive controls are load-control devices that are owned and
controlled by the customers themselves.They can be used to control
water heaters,and most significant electrical loads within a home.
3.Incentive pricing of electricity allows the customer to take
advantage of reduced electricity rates by voluntarily shifting his
use of electricity to off-peak periods where rates are less.This
is a means of achieving load management objectives through the
market mechanism.
4.Education and public involvement programs are designed to appeal to
the public to voluntarily reduce and change electricity consumption
patterns for their own benefit and for the overall public economic
well being
5.Dispersed thermal energy storage stores heat produced during
off-peak periods for use in space or water heating during peak
periods.Thermal storage systems may range in size from large
central storage units to residential-scale devices.Water is the
most commonly used fluid for storage because of its abundance,low
cost,nontoxic nature,and relative ease of handling.
COST-EFFECTIVENESS OF LOAD MANAGEMENT ALTERNATIVES
Load management programs are effective if the energy cost savings exceed
the added cost of alternative electricity generation and transmission plus the
costs of implementing load management techniques.Effective load management
will reduce operating requirements for peak and possibly intermediate load
capacity.The need for new peaking capacity may also be deferred.
SOCIAL AND ENVIRONMENTAL CONSIDERATIONS
Successful load management rests on the premise that certain individual
choices can be opted in favor of a "fatr "program developed for all
customers. In most areas where load management has been tried,programs have
been well accepted.With an effective public communications program by local
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utilities,similar results can be expected in the Railbelt region as the need
for such programs grow in the future.Delays or elimination of new electric
generation facilities can be expected to defer associated environmental
problems.
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ELECTRIC ENERGY CONSERVATION IN BUILDINGS
Four factors determine the energy efficiency of any building and,if
implemented,offer the greatest potential for energy savings in both new
construction and retrofit of existing structures:
1.an insulation envelope to reduce conduction of heat through the
building structure
2. adequate sealing to minimize in filtration of air
3. a vapor barrier to retard moisture transfer
4.efficient space heating and hot water systems.
POSSIBLE RAILBELT APPLICATION
Most buildings constructed in the Rai1be1t use materials and techniques
better suited for temperate climates.Only recently have builders and
designers begun to recognize the need for an "Alaska-spectflc''approach for
designing a building's thermal envelope.Some individuals in the Rai1~e1t
have reduced their fuel bills as much as 70%by adding extra insulation and by
thorough sealing.Energy-conserving retrofit methods in existing structures
and energy-conserving measures in new construction will receive increased
emphasis as the cost of energy increases.Electricity demand through
conservation will not be significantly reduced while low-cost electricity is
widely available.
COMMERCIAL AVAILABILITY
Energy conservation measures are widely used, although most people are
still not aware of the techno10gy's economic benefits.Well-developed
technology is available on optimizing the use of insulation to reduce
conduction on sealing to reduce air in.filtration,on constructing properly to
retard moisture transfer,and on optimizing space heating and hot water
systems.
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COST AND PERFORMANCE
Conservation benefits are difficult to measure on an area-wide basis due
to its dispersed nature.Retrofit costs can vary substantially,depending on
each dwelling1s age and type of construction.When comparing a "typ tca l'
existing Alaskan house in the Railbelt region,adding retrofit conservation
measures could return savings of 41.8%of the typical annual heating load.
For new construction on a house costing $100,000,"superinsul at ton"can cost
an additional $7,000. In an Alaska-specific designed residence,where
conservation (llsuperinsulation ll
)was built into the structure,savings
amounted to 72.3%over the "typ tcal"Alaskan home.
ENVIRONMENTAL IMPACTS
BUilding conservation technologies have few detrimental environmental
impacts.Because bUilding "styles"would not change significantly,the
technology need not have any impact on community appearance.
The impact on occupants of buildings having a minimum of air exchange is
being assessed.The major area of concern relates to the quality of indoor
air as measures to reduce infiltration or the introduction of outside air are
incorporated.The potential for adverse health impacts is increased as the
rate of interior air exchange is reduced.The safe level is difficult to
establish,however,as it depends on building-specific pollutant sources.
Air-quality concerns can be rectified with air-to-air heat exchangers.The
exchangers are available at modest cost to exchange "st ale"inside air with
"f resh"outside air while conserving 60 to 80%of the energy content.
SOCIOECONOMIC IMPACT
The socioeconomic impact of energy-conserving technologies are not
expected to be great.An energy-conserving building is comfortable and
relatively draft free.The reduced cost of heating allows occupants to keep
the building warmer for less money.Additional jobs are expected to be
created from the manufacture,sale,and installation of conservation materials
and services.
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ELECTRIC ENERGY SUBSTITUTES
Electric energy substitutes include passive solar space heating,active
solar in hot water and space heating,and wood space heating.Dispersed
active solar technologies differ from passive solar in that they require
auxiliary pumping energy to function properly.Passive solar energy
applications require very little or no auxiliary energy.
PASSIVE SOLAR SPACE HEATING
Passive solar systems rely on a combination of a thermally efficient
building envelope to contain heat,south facing windows to capture solar
energy,some form of thermal mass to store captured energy for release at
night or during cloudy periods,and design techniques to distribute heat by
convection. Passive solar uses no mechanical means such as pumps or fans to
distribute heat from the sun into the living space.
Possible Applications to the Railbelt
Although passive solar for space heating is fairly new in the Railbelt,
several buildings that rely on the sun for a large portion of their heating
needs have been constructed in the last few years.Passive solar may appear
to be an inappropriate technology for the Railbelt because the resource is
providing a minimum amount of energy when the need is greatest (December and
January).However,the high heating loads and length of the heating season
make passive solar attractive.During late winter and early fall,a properly
designed, passive solar structure in the Railbelt region can obtain a large
part of its space heating needs from the sun.
Commercial Availability
Hundreds of passive solar structures are now working successfully in the
United States.The technology for incorporating passive solar features in new
construction is well developed and is continuing to expand.
Performance
A combination of energy conservation and passive solar in new
construction can cut energy demands by 60 to 70%in an individual dwelling.
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Although the potential of passive solar and conservation in existing buildings
is difficult to quantify without knowing the structure's existing condition
and solar access,incorporating this technology in existing structures could
reduce the heating load by an estimated 30 to 50%.Several structures in the
Railbelt are using 25 to 30%as much space heating as their neighbors by
combining an efficient therm~l envelope (conservation through insulation
addition and minimizing air leakage) with passive solar heat.
Cost of Implementation
Virtually no work has been done for the Railbelt on capital costs for
passive solar.Preliminary studies show an increase of between 6 and 10%
above normal construction costs for a passive solar,super insulated home.
The estimated unit energy costs for installation of passive solar and super
insulation in a new residence ranges from $4.49/MMBtu for a 10%,30-year term,
$6,000 state loan to $5.86/MMBtu for a 5%,20-year term,$10,000 alternate
energy loan. This compares with fuel oil,which is in the $8.20 to 8.40/MMBtu
range in the Railbelt area.
Insolation
Insolation is the total amount of all solar radiation that strikes a
surface exposed to the sky.Insolation varies throughout the Railbelt region,
but has an overall average of about 300,000 Btus per square foot per year.
While this insolation value is less than half of what one might expect in New
Mexico,for example,the long heating seasons and high heating loads justify
use of available radiation.
Environmental Consequences
Environmental impacts from passive solar technologies are minimal.
Aesthetic concerns for passive solar structures can be handled by proper
design. Reflected glare off south facing windows is a potential problem in
passive solar applications.Proper building design and introduction of new
glazing materials are expected to control glare within acceptable limits.
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Socioeconomic Impacts
The socioeconomic impacts of passive solar technologies for space heating
centers in the areas of land use,consumer convenience and control,and
regional economics.Land-use planning would need to be implemented to prevent
the degradation in efficiency of an individual solar application by a building
being placed in the sun's path at a later date.Increased consumer benefits
can be expected through reduced fuel expenditures,low maintenance of passive
solar systems and greater security from having an independent energy source.
Introduction of passive solar on a broad scale is expected to create jobs and
new capital ventures at a local and regional level.
Development of a thorough understanding of the economy of various levels
of passive solar design followed by education of designers,developers,
builders,and consumers is the key to successful implementation of solar
technologies.
ACTIVE SOLAR SPACE AND HOT WATER HEATING
"Active"solar systems require auxiliary pumping energy to function
properly.Systems employing flat-plate collectors are the most common type
used to retrofit homes and businesses.In these systems either a liquid or
air is heated directly (or indirectly)within a closed,usually flat,
collector.Heated air or a liquid is then usually stored directly or its
energy transferred"to another media;e.g.,a rockbed for use during periods of
high load.
Possible Railbelt Applications
Like passive solar systems,active solar for space heating in the
Railbelt region appears to be inappropriate because the building heating load
is greatest when the resource (solar radiation)is at its minimum.However,
in many parts of the Railbelt,space heat is needed at least 9 to 10 months of
the year.While active solar will not make a significant contribution to
heating during mid-winter months in the Railbelt,it can reduce heating bills
on an annual basis.Assessing the future level of application for active
solar systems in the Railbelt region is extremely difficult because of a
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fundamental lack of information at all levels of the supplier user and
financial communities.Unless technical and economic feasibility of active
solar systems has been clearly demonstrated to the satisfaction of those who
remain skeptical,widespread introduction of this within the Railbelt region
will be inhibited.
Commercial Availability
Active solar system technology is well developed, with many thousands of
installations throughout the United States.Active solar collectors,largely
of local assembly,are currently available in the Railbelt.Technical
assistance from designers,installers and dealers in optimizing the collector
with the specific installation may not be available because of limited
operating experience with this equipment in the Railbelt region.
Performance
In the Railbelt under optimum conditions,active solar collectors can be
expected to make use of 30 to 40%of the sun's energy that strikes its
surface.The presence of obstructions in the sun's path,the tilt of the
collector and whether the heat is used directly or indirectly all have a
significant impact on collector efficiency.The interaction of these
variables and the low temperatures for 1 to 3 months has never been studied in
Alaska.
Costs of Implementation
Costs of energy for active solar energy will likely vary between 12.50
and 34.20 $/MMBtu,depending on the type of system installed,the amount of
collector used and the efficiency of the end use of the system.These unit
cost figures are projections only.As additional systems are installed,a
much better understanding of initial capital costs will be possible.
Insolation
Insolation is discussed under this section in "Passive Solar for Space
Heating."
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Environmental Consequences
The environmental effects of active solar energy use are minimal.
Earlier concern over the aesthetic devaluation of neighborhoods from many
roof-mounted solar collectors has been replaced in the southern United States
by the increased real estate appraisal values for homes with solar systems.
Socioeconomic Impacts
Socioeconomic impacts of active solar systems would be similar to pther
dispersed technologies.As a result,a higher percentage of the cash flow
would tend to stay in the region for a dispersed technology than for a large
centralized project.In addition,the impact on one1s life style from the
active solar systems differs from the effect of passive solar systems.The
potential benefits from reduced fuel usage and subsequent dollar savings are
obvious.Some user maintenance will be associated with active systems,
amounting to perhaps 3 to 6 hours per month for a well-designed system.
WOOD-FIRED SPACE HEATING
Wood has been a traditional fuel for space heating in Alaska. A
sign ifi cant amount of wood conti nues to be used in the Ra i 1be1t as a pr imary
and secondary heating source.Fireplaces have largely been replaced by a
variety of fireplace modification equipment (e.g.,fireplace inserts)and
stand-alone stoves,both of which have greatly improved wood burning
efficiency over the standard open fireplace.
Possible Railbelt Applications
Recent studies point to a dramatic increase in wood burning in Railbelt
residential areas.Many people,usually outside the larger urban areas,
depend on wood for their sole heating source. In the larger population
centers,wood heat tends to be more of a secondary source, although this may
be changing to some degree.An expanded use of wood for space heating in the
future will depend on the continued availability of wood fuel,the relatively
low transportation fuel costs,the availability of low-cost electricity and
hydrocarbon fuels,and the introduction of residential conservation methods.
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Although determining the amount of space heating energy that wood-fired units
could contribute to the region is difficult,eventually,10 to 15%of total
demand should be quite realistic.
Commercial Availability
Technology is well developed for wood burning systems.Suppliers of wood
burning units in the Railbelt could meet considerably greater demand for both
primary and secondary heating systems. Available equipment includes models
that can accommodate hydrocarbon fuels as well as wood and that are adaptable
to incremental increases in heating capacity without major system changes.
Conversion Efficiency
Conversion efficiencies for wood-burning equipment varies widely.The
effectiveness of these systems is indicated not only by Btu output,but also
by the ability to put the heat into the structure instead of losing it to the
chimney.Conversion efficiencies of open fireplaces range up to 10%.The
popular box stove (e.g.,kitchen,Franklin,potbelly and parlor stoves)have
conversion efficiencies of 20 to 30%;air tight and controlled draft stoves
can have efficiencies between 40 to 65%.
Costs
Space heating costs using wood compare very favorably with other sources,
especially when the wood is harvested by the dispersed,individual method.
This situation is expected to continue unless transportation fuel costs rise
dramatically.The unit cost for wood heating over the life of the structure
is difficult to assess because of the uncertainties of future firewood costs
to the user.The installed cost of a wood-burning unit will also impact unit
cost and can range from $300 to $6000 depending on the application used. In
costs per MMBtu,wood fuel ranges between $5.48 and $6.30 for Fairbanks and
Anchorage,respectively.Fuel oil (January 1981 prices)for the same two
locations ranged from $8.19 to $8.41/MMBtu.
Resource Availability
Although the dispersed individualized process of harvesting wood for fuel
in the Railbelt area is not highly visible,demand for firewood has increased
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dramatically.Birch is the most common wood in the Anchorage area,while
spruce is most common in Fairbanks.Wood is harvested on state and private
lands but a greater amount is taken from private lands being cleared for
development.Wood suppliers indicate that their sales are limited by
accessibility to harvest areas and not by resource shortage.Forest
management officers confirm that while the resource is sufficient to meet
anticipated future demand,it must be made accessible for public use.
Environmental Consequences
Wood for heating poses three environmental issues:fire hazards,air
quality effects,and environmental degradation from wood harvesting.Fire
hazards increase with expanded use of wood for fuel.Most wood-burning-related
fires are the result of improper installation and, to a lesser extent,
operation.Following recommended installation and maintenance procedures for
wood-burning systems can considerably reduce the hazard level.Air-quality
monitoring in the Anchorage area has not detected particulates attributable to
wood combustion.Monitoring for suspended particles in other Railbelt
locations has not yet begun.Wood smoke creates a visual and odor impact for
some people, although this does not appear to be a major problem.The degree
of environmental degradation from harvesting wood fuel will depend upon
harvesting methods and enforcement of land-use regulations.
Socioeconomic Considerations
An important aspect of wood for fuel for many is that it provides an
independent source of heat in case of power failure.Unlike other heat
sources,wood fires require regular attention,and for those harvesting their
own wood,a considerable investment of time cutting,splitting,and stacking
the wood.Some adjustments in life style might be necessary,particularly for
those who wouldouse wood as a primary space heating fuel.Land-use issues of
wood harvesting must be addressed to assure a dependable long-term supply of
wood.
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