HomeMy WebLinkAboutRe-Evaluation of Alternatives for Electric Generation Program 1976-
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Orlando, Florida
CITY AND BOROUGH OF SITKA, ALASKA
1
",OPERT\' , Of,
Alaska power Authority
..... 34 W 5th Ave. , ~. ~1
Anchorage, Alaska
RE-EVALUATION
OF
ALTERNATIVES FOR ELECTRIC GENERATION PROGRAM
R. W. BECK AND ASSOCIATES, INC.
Engineers and Consultants
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Seattle, Washington Columbus, Nebraska
Wellesley, Massachusetts Denver, Colorado Indianapolis, Indiana
Phoenix, Arizona
SEPTEMBER 1976
(2) September 27, 1976
We consider that this type of inconsistency makes. the estimated costs shown in
the University of Alaska report invalid for use as a basis for selection of a
definite power generation program for Sitka.
Sitka's loan from the Revolving Loan Fund has been approved on
the condition that other hydro power projects in the area listed in the University
of Alaska report be re-examined. As discussed, we have therefore proceeded to
briefly re-evaluate the alternatives and, in doing so, have confirmed that the
Green Lake Project will result in the most economic and reliabl~ power, and is of
the size needed for the next hydroelectric project to be developed. It shows
that for alternatives entering into service in late 1978 (a comparative but not
practical schedule) Green Lake power would cost 40.3 mills/kWh of average annual
generation, and the nearest hydro in cost, Takatz Lake, is 55.1 mills/kWh, while new
diesel generation would cost 50.9 mills/kWh. Green Lake is the only way to go.
If you have any questions or comments on this report we would be
pleased to answer them.
JVW/cg
Very truly yours,
R. W. BECK AND ASSOCIATES, INC.
~J0~~
James V. Williamson
Assistant Manager
Western Design Office
CERTIFICATE OF ENGINEER
ELECTRIC UTILITY SYSTEM
SITKA, ALASKA
RE-EVAL UAT ION
OF
ALTERNATIVES FOR ELECTRIC GENERATION PROGRAM
The technical material and data contained in this report were pre-
pared under the supervision and direction of the undersigned whose seals, as
registered professional engineers licensed to practice, are affixed below.
Donald E. Bowes
Executive Engineer
R. W. Beck and Associates, Inc.
~t/~~
James V. Williamson
pervising Executive Engineer
R. W. Beck and Associates, Inc.
SECTION I
LOADS AND EXISTING RESOURCES
In this analysis a projected load growth of 6% annually was derived
in conjunction with the Sitka Electric Department. Sitka has experienced a 5%
average annual growth rate since 1962 (see Table 1). However, an annual growth
Tate of 6% is consistent with the average of recent the projections taking into
account additional block loads from the Coast Guard and other sources as shown
in Table 2. It is considered, if a~ything, to be on the low"end of the scale
for generation planning purposes since it is on the low end of the 6%-8% range
forecast for Southeast Alaska in the University of Alaska Study, and it is less
than 7-11% mid-range growth forecast by Alaska Power Administration (APA) in its
Alaska Power Statistics 1960-1975.
Sitka's existing generating capacity consists of 7,000 kW of genera-
tion delivered from Blue Lake and 3,100 kW of diesel capacity. The City also
has a 2,500 kVA tie with the Alaska Lumber and Pump Company (ALP) thermal in-
stallation but the amounts of capacity and energy available from ALP are dimi-
nishing rapidly as ALP expands towards full capacity, and this tie serves main-
ly for exchange of power and reserves both ways. In fact, it is our understand~
ing that ALP has recently requested an expansion of the capacity of the intertie
so as to be able obtain additional power from Sitka. The 6% annual load growth
rate has been plotted in Fig. 1 through 4, through 1991, together with Sitka's
existing generating resources, and the output from future generating alternatives
to be subsequently discussed. The capacity peak load plus reserve line is based
on reserves equal to the largest single generating unit in the system. Power
year is defined as extending from July through June.
As can be seen from the Figures, Sitka now has no capacity reserves,
and little energy reserves except diesel, and by mid-1977, with the 6% growth
rate plus the above average new loads, Sitka will need new peak load capacity
even with no reserves. The City's generating system will require the installa-
tion of 2-2,500 kW units of additional diesel capacity, before any hydroelec-
tric capacity could reasonably be assumed to be in service, which is mid-198l
for Green Lake, and later for other alternatives which have not been as well
studied to date.
SECTION II
CONSIDERATION OF FUTURE GENERATION ALTERNATIVES
The need is apparent. The basic issue becomes which of the alter-
natives available should be developed as Sitka's next major power source. It
is important to note that the alternative selected to proceed with first should
provide a significant amount of energy and capacity in view of Sitka's load
growth situation and the fact that the earliest date that any hydro project
could be brought on-line would be mid-19Bl, and this could only be Green Lake.
Others would take longer as more investigation remains. By the time the next
hydro unit is brought on-line, the demand for power will have increased nearly
75% based on the 6% growth rate plus additional block loads. Hence the next
hydro project should, in combination with existing resources, be capable of ac-
commodating this growth plus some reasonable period beyond.
The alternatives evaluated herein included Takatz Lake, Carbon Lake,
Lake Diana, Green Lake, Blue Lake Expansion, Lake Irina, l1ilk Lake and Four Falls
Lake. Their locations can be seen on Fig. 5, Vicinity Map. Some of these alter-
natives can initially be eliminated as not being acceptable for the initial de-
velopment or as being very comparable to another alternative being considered.
In this regard, Lake Irina, Milk Lake and Four Falls Lake were dropped from fur-
ther consideration at this time for the reasons discussed below.
Lake Irina, at 3,000 kW, was eliminated as being too small to war-
rant consideration for initial development. This view is also supported by the
University of Alaska report, since the transmission line cost estimate therein
for Irina ,vas based on line construction extending only to Lake Diana apparentlY
presuming Diana wo~ld be developed first. Incidentally, in the same manner,
Diana's transmission line cost estimate in that report presumed the previous
construction of Green Lake.
Milk Lake was not analyzed since it is considered to be comparable to
Carbon Lake with a very significant proportion of its development cost being in
transmission line construction thereby outweighing any other economies. If Car-
bon had turned out to be more promising Milk would have been examined more close-
ly.
Four Falls Lake was eliminated for reasons similar to ¥~lk' Lake. How-
ever, its limited capacity (6,000 kW) would make it a questionable alternative any-
way as the first project. The marginal capacity would be further reduced by the
long line transmission losses to Sitka. Again the University of Alaska report
apparently supported this conclusion since its transmission line cost estimate
for Four Falls reflected the pre-supposed prior construction of Milk Lake and of
course gives a misleading impression of the true cost of the smaller project.
The alternative of Takatz Lake is shown in Fig. 1 and would come on-
line at the end of 19B2; Carbon Lake in Fig. 2 on the same schedule, Lake Diana
in Fig. 3 also on the same schedule; and Green Lake in Fig. 4 coming on-line by
mid-19B!.
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SECTION III
ALTERNATIVE PROJECT CHARACTERISTICS
1. GENERAL
As can be noted from Fig. 5, all of the sites under consideration
are located generally either on the east or west side of Baranof Island. As a
result of climatic conditions, the average annual runoff for streams on the
west side of the island typically ranges in the vicinity of 10 cubic feet per
second per square mile of drainage area, while streams on the east are a little
more than fifty percent higher, or around 16 cfs per square mile.
Annual runoff patterns of streams in this area are also significantly
affected by the relative elevation of their drainage basins and the nature of
their tributaries. Streams with basins at lower elevations or which have sub-
~tantial glacial runoff contributions tend to have more uniform runoff patterns
throughout the year, whereas streams with basins at higher elevation, having
'little or no glacier inflow, tend to dry up more during the winter months and
have greater concentrations of spring runoff. This effect is in part the re-
sult of the more severe winter freeze-up that occurs at higher elevations stor-
ing the precipitation as snow and ice and releasing greater concentrations of
runoff during spring thaw. Glaciers tend to thaw at a uniform rate thus stabi-
lizing runoff. The effect of this on hydroelectric development, is that to
avoid large spring spills and loss of potential generation greater amounts of
reservoir storage must be provided for higher drainage basins with little or
no glacial contribution, in order to provide sufficient regulated flow during
the winter months which are the typically the peak load months for Sitka. Run-
off characteristics for Southeast Alaska are discussed at greater l'ength in Water
Powers of Southeast Alaska, published by the Federal Power Commission (FPC)
and u.s. Forest Service in 1947.
In conSidering the development of each project, transmission losses
for capacity and energy were estimated. As would be expected this effect is more
pronounced for those sites which are more distant from Sitka on the eastern side
of Baranof Island.
2. CHARACTERISTICS
The following ~s a discussion of the characteristics of each alter-
native site considered and the scheme of development proposed for it. Project
data is summarized in Table 3. The energy quoted as being available from each
project is estimated average annual energy, a value of course generally greater
than the firm energy amou~t. As is done elsewhere, and is the procedure now be-
ing utilized by the FPC in economic analysis of hydro generation, where thermal
(diesel) resources are available within the system as at Sitka they are used to
firm up the difference between the average annual and firm generation (secondary
energy) during the infrequent low flow periods.
III-2
a. Takatz Lake
Takatz Lake, located on the east side of Baranof Island, has been
studied extensively by the APA and was the subject of a report published in
1968. Our Firm conducted an additional evaluation of the project in the 1974
Sitka report. Takatz basin is the highest of the basins considered; however,
its flow is stabilized somewhat by some glacial contribution. A large amount
of reservoir storage is still required for maximum development. The APA study,
and our studies in 1974, indicate that the 82,400 acre~feet of reservoir storage
developed will yield an average regulated flmv of around 160 cfs from 166 cfs of
runoff. This would require construction of a 200-foot high concrete arch dam and
3,800-foot long power conduit consisting of part tunnel and part penstock. This
scheme would develop an average net head of 950 feet.
With an installed plant capacity of 27,700 kW at 41% plant factor,
approximately 25,000 kW of capacity and 93,330,000 kWh of average annual energy
would be delivered to Sitka after allowing for station service and substation
losses, and losses over approximately 31.2 miles of 69-kV transmission line. The
line would extend through a 2,800-foot high pass near the center of the island
considerably complicating construction.maintenance and reliability. Development
of a port facility and a short access road from tidewater to the project would
also be required. It should be noted that the APA and University of Alaska re-
ports show 20,000 kW installed capacity based on a higher plant factor.
b. Carbon Lake
Carbon Lake is located on the east side of Baranof Island almost due
east of Sitka where it empties via a short length of falls directly into Cascade
Bay. To date Carbon Lake has not received a great deal of consideration as a
generating source, the only significant mention being in Water Powers of South-
east Alaska. The elevation of the Carbon Basin is the lowest of those consider-
ed herein and the basin is glacier fed which tends to stabilize the flow. Water
Powers of Southeast Alaska estimates that 53,000 acre-feet of storage would firm-
up approximately 270 cfs of the estimated annual average 444 cfs of runoff avail-
able. On this basis it is estimated that an average annual flow of 333 cfs, or
75% of the long-term average, could be regulated by the 53,000 acre-feet of stor-
age. Development of this storage would require the construction of four dams
ranging in height from 10 feet to 65 feet. A 4,800 foot power conduit would in-
clude 2,000 feet of tunnel and the remainder in penstock. The powerhouse would
be located at tidewater developing an average gross head of 230 feet.
This arrangement would permit the installation of 13,500 kW o'f capa-
city at a 40% annual plant factor. Allowing for substation losses and losses
over a 31.4 mile transmission line to Sitka, 12,150 kW of capacity and 43,674,000
kWh of energy would be delivered to the load center. The transmission line route
would be generally the same as for Takatz and a port facility would also be re-
qUired. The above installed capacity does not compare with the 18,000 kW cited
in the University of Alaska report which is evidently based on 100% regulation
not possible with the contemplated reservoir size.
1
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111-3
c. Lake Diana
Lake Diana is located on the western side of Baranof Island approxi-
mately 8 air miles southeast of the southern tip of Silver Bay. Even less study
has been completed on Diana than on Carbon Lake. The Lake is at approximately
elevation 1,728 and has a drainage area of about 3.5 square miles. Using an
average of 10 cfs of runoff per square mile of drainage area results in an esti-
mated average annual runoff of 35 cfs. Lake Diana is by far the highest lake
under consideration and it has no glacier contribution. It is considered that
the winter freeze-up effect will significantly limit the amount of runoff that
can be economically regulated.
No site reconnaissance has been made and therefore no specific de-
termination of dam type or reservoir size was attempted. However, it is assumed
the lake would have to be dammed at its ~utlet and three possible layouts were
compared. To minimize high elevation transmission line cost maintenance and re-
liability problems, the power conduit would exit the north end of the Lake via
tunnel and" then extend a little less than one mile north by penstock to a power-
house located on the eastern tributary of Redoubt Lake. This would result in
the development of an estimated gross head of approximately 1,000 feet. To com-
pensate for winter freeze-up, it is estimated that an average annual regulated
discharge only 75% of the annual runoff of 35 cfs, or 26 cfs, can be utilized
for determining the amount of generation. This will permit installation of
5,000 kW of capacity at 38% plant factor. Allciwing for losses in transmission,
this would result in an estimated 4,700 kW of capacity and 15,603,000 kWh of
average annual energy delivered at the load center.
The University of Alaska report shows 10,000 kW of installed capa-
city and 40,165,000 kW of energy. No details are given but the reason for the
higher capacity is probably due to assumed development of the full head to tide-
water which would require an exhorbitantly long penstock (about 3 miles). Even
so, no allowance was made in that report for winter freeze-up so the energy is
substantially overstated. If Lake Diana were developed first, approximately 2i.6
miles of transmission line would be required to connect with Sitka's load center
and an access road approximately 16.7 miles long would be required to connect the
powerhouse with the existing road at Sawmill Bay. Transmission line alignment
would parallel the access road.
d. Green Lake
We are familiar with the development proposed for Green Lake having
studied it in detail in 1974 and additionally since then. APA also studied this
project in 1968. The lake is located on the west side of Baranof Island near the
southern tip of Silver Bay. It is situated on the Vodopad River approximately 1,500
feet upstream from its mouth at Silver Bay, and drains a basin of approximately 28.9
square miles with an average elevation of 2,150. The basin is relatively low in
elevation and subject to more uniform annual runoff patterns. Ave"rage annual run-
off is estimated at 291 cfs.
111-4
The development 'currently proposed would consist of a 2l5-foot high
concrete arch dam resulting in an active storage of 112,000 acre-feet. A 1,600-
foot power conduit, would terminate at a powerhouse constructed at tidewater.
Approximately 7 miles of new access road would be required to connect with the
existing road at Sawmill Cove, at the Blue Lake Project. Approximately 7 miles
of new transmission line paralleling the access road l-1Ould connect to the Blue
Lake substation, and the 5.9 mile long existing 34.5-kWtransmission line to
Sitka would be upgraded to 69 kV. This arrangement would develop an average net
head of 352 feet and result in an average annual regulated discharge of 285 cfs.
With an installation of 16,600 kW (45% plant factor) allowing for transmission
and related losses, 15,770 kW of capacity and 62,817,000 kWh of average energy
would be delivered to the load center at Sitka.
e. Blue Lake Expansion
This proposal was discussed in detail in our 1974 Report. It is a
feasible alternative to provide 4,000 more kW of capacity; however, no additional
energy results. For this reason, no further discussion will be made of it at this
time.
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SECTION IV
ESTIMATED CAPITAL COSTS
1. GENERAL BASIS
Estimates were developed of the capital investment required for each
of the alternatives under consideration. These values were based on the data
developed for our 1974 Report and experience with similar projects in Alaska,
either completed or under consideration. For economic comparative purposes, costs
were developed assuming contract bids were issued in January 1976 for all alter-
natives which would result in construction completion in September (late) 1978
after a 2-3/4-year construction. The costs are therefore, representative of in-
service in late 1978 and do not reflect escalation to the in-service dates shown
in Figs. 1 through 4. The required capital investment is the sum of direct con-
struction cost, contingencies (15%), engineering (15%), and interest during con-
struction at 10% assuming 6% cost of money and a 2-3/4-year construction period.
Construction costs for transmission lines and roads have been iden-
tified separately because they represent, in some cases, a major portion of the
total cost. These costs were determined using unit costs based on estimates
prepared by us, the Corps of Engineers, and the Bonneville Power Administration,
with adjustment for local conditions where appropriate. Permanent one-lane
project access roads with turnouts were estimated to have a direct construction
cost of $265,000 per mile based on entering into service in late 1978. A69-kV
transmission line built alongside a permanent project road was estimated to have
a direct construction cost of $112,000 per mile in the same time frame. The same
transmission line built cross-country with only a temporarJ construction access
road is expected t9 have a direct construction cost of $225,000 per mile includ-
ing the construction road. It is possible that some transmission lines might be
built utilizing helicopter construction techniques thus eliminating the need for
the construction road; however, the cost difference with that method is not ex-
pected to be significant even though there might be environmental benefits. The
estimated direct construction cost for development of a new port facility such
as_would be required for Takatz or Carbon Lake where no access road is included,
is $1,500,000. The magnitude of the transmission line costs generally relates
to the construction difficulties associated with the rugged terrain and inacces-
sibility, costs of meeting environmental constraints, and the high costs of con-
tractor mobilization.
The capital investment costs developed for the alternatives consid-
ered are discussed below and summarized in Table 4.
2. TAKATZ LAKE
The estimate of the direct construction cost for Takatz Lake is based on
our 1975 Report estimate of $925 per installed kilowatt for bidding in January
1974, and considering the intervening escalation results in capital investment
of $1,885/kW based on issuing contracts bid in January 1976. 31.2 Miles of
cross-country transmission line plus 1 mile of access road add another $389/kW
of capital investment for a total of $2,274/kW, which amounts to $62,990,000.
IV-2
3 • CARBON LAKE
The estimated capital investment required for development of Carbon
Lake was based on comparison with development costs for Green Lake, and those
developed by the U.S. Bureau of Reclamation for the Swan Lake Project near
Ketchikan. Recent estimates which we have prepared place the capital invest-
ment for Slyan Lake, based on January 1976 bid at about $1, 985/kW. An average
gross head of 295 feet is to be developed at Swan Lake. Carbon Lake will have
a lower head and generally a more complex arrangement with four dams and a
port facility. Based on these considerations, the per kilowatt capital invest-
ment for Carbon was estimated at $2,000/kW, plus the cost of a port at $164/kW.
This value was supplemented by capital investment required for the cross-country
transmission line to Sitka and the short access road to the port and resulted in
a total capital investment of $2,967/kW, which amounts to $40,055,000.
4. LAl<E DIANA
As has been noted previously little is known about the Diana site so
it was necessary to estimate the capital investment based on per kilowatt costs
of comparative sized projects with allowance for construction difficulties. It
is considered that the per kilowatt capital investment for Diana (at 1,000-foot
head) would fall between Mahoney Lake (at 1,860 foot head) and Lake Whitman (358-
foot head) located on Revillagigedo Island. Estimates were recently completed by
us for-these two projects for Ketchikan placed their capital investment require-
ments at $1,840/kW and $2,300/kW respectively for on-line in late 1978. $2,100/
kW was selected as being a reasonable value for Diana to which was added the capi-
tal investment-required for 16.7 miles of access road and 22.6 miles of transmis-
sion line built along existing access road amounting to $2,034/kW. This result-
ed in a capital investment requirement of $4,134/kW which amounts to $20,670,000
based on January 1976 bids. It can be seen that for a small relatively remote
project the transmission and road costs will more than double the cost of the
project.
5. GREEN LAKE
Capital investment requirements for Green Lake were developed from
our latest estimates as being $1.575/kW in January 1976. To this was added the
capital investment required to construct 7 miles of permanent access road and
12.9 miles of transmission line built along an existing road in the amount of
$291/kW. This results in a total capital investment of $1,866/kW based on bidding
in January 1976, and amounts to $30,976,000.
SECTION V
ANNUAL COSTS AND THE COST OF POWER
Estimated annual costs for all alternatives were developed based on
6%, 40-yea~ term financing which it is expected will be available through the
Water Resources Revolving Loan Fund. Financing costs are estimated at 0.2% of
the capital investment. Operation and maintenance costs amount to 1.5% of the
capital investment based on FPC experience data. The estimated total annual
cost and the resulting cost of pOl-ler are shown in Table 4. At 40.3 mills/kWh
of average energy delivered, Green Lake provides the most economic hydroelectric
power; the closest cost is Takatz at 55.1 mills/kWh. Further the Green Lake
Project provides significant advantages over the other alternatives in terms
of its reliability and close proximity to the Blue Lake Project and its trans-
mission system.
The cost of Green Lake was also compared with an equivalent amount of
diesel generation and is summarized in Table 5. Alternative diesel generation was
based on current costs including fuel, escalated to on-line in late 1978, at a
7% annual escalation rate. It shows that for a late-1978 on-line date the cost
of equivalent diesel replacement power for Green Lake would be approximately 50.9
mills/kWh or about 25% more than Green Lake.
TABLE 1
CITY OF SITKA
SUMMARY OF LOADS
1962 -1976
Peak
Load Energy
Power Year kW Month 1,000 kWh
1962-63 18,419.2
.1963-64 5,500 Nov. 22,220.9
1964-65 6,500 Dec. 24,544.5
1965-66 4,950 22,368.4
1966-67 5,300 Jan. 22,872.7
·1967-68 5,150 Jan. 24,658.2
1968-69 5,300 Jan. 25,728.1
1969-70 5,300 Jan. 26,640.6
1970-71 6,200 Dec. 28,889.0
1971-72 6,050 Dec. 29,979.5
1972-73 6,050 Jan. 30,653.7
1973-74 5,950 Nov. 29,308.8
1974-75 7,100 Jan. 32,205.1
1975-76 7,200 Dec. 36,254.1
Note: All loads adjusted for historic transfers to and from ALP.
ADDITIONAL LOAD GROWTH NOT ANTICIPATED
IN NORMAL PROJECTIONS
1976-77
Coast Guard Facility 1,120 kW
City Garbage Grinding Installation 200 kW
TOTAL 1,320 kW
1977-78
Tlingit-Haida Housing Authority 300 kW
Housing for the Elderly (24 units) 185 kW
Potter Housing Unit (18 units) 120 kW
U.s. Forest Service Duplexes 37.5 kW
Sheldon-Jackson College 10 kW
Sitka Port Development Project 600 kW
TOTAL 1,252.5 kW
TABLE 2
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TABLE 3
PROJECT CHARACTERISTICS
2 Drainage Area (mi ) •••••••••••••••••••
Ave. Drainage Area Elevation ••••••.•.•
Ave. Annual Runoff (cfs)
Active Reservoir Storage (AF) ••••••.••
Ave. Annual Regulated Discharge (cfs).
Average Gross Head (ft.) •••••••••.••••
Installed Generating Capacity (kW) .••
Capacity Delivered at Load Center (kW)
Average Annual Generation (k~fu) .•••••
Ave. Annual Energy Delivered at Load
Cen ter (kWh) .•.••••••••••••.•••••••
Annual Plant Factor (at Plant)
Takatz
Lake
10.6
2,480
166
82,400
162
950 (net)
27,700
25,000
99,864,000
93,330,000
0.41
Carbon
Lake
26.6
2,000
444
53,000
333
230
13,500
Lake
Diana
3.5
2,280
35
NA
26
1,000
5,000
12,150 4,700
46,962,000 16,425,000
43,674,000 15,603,000
0.40 0.38
Green
Lake
28.
2,150
291
112,000
285
352(
16,600
15,770
65,096,000
62,817,000
0.45
TABLE 4
CAPITAL INVESTMENT, ANNUAL COSTS, AND COST OF POWER
FOR GENERATION ALTERNATIVES
Takatz Carbon Lake Green
Lake Lake Diana Lake
ESTIMATED CAPITAL INVESTMENT:
Estimated Base Project(l)
Capital Investment ($/in-
stalled kW), 1,885 2,164 2,100 1,575
(Excluvsive of transmission
line, access road, but in-
cluding port facility for
Takatz and Carbon)
Estimated Capital Investment(l)
for Transmission Line and
Access Road ($/kW) 389 803 2,034 291
Estimated Total Project
Capital Investment, ($)
($1 ;000) 62,990 40,055 20,670 30,976
ANNUAL COST: (2)
($1,000) 5,142 3,270 1,687 2,529
COST OF POWER: 55.1 74.9 108.1 40.3-
(Mills/kWh in late 1978)
(1) Based on-January 1976 Bid and September 1978 on-line.
(2) Based on Financing Costs at 0.2% of Capital Investment, 6% -40 year
debt service, O&M at 1.5% of Capital Investment.
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DIESEL REPLACEMENT COSTS
FOR
GREEN LAKE PROJECT
CAPITAL INVESTMENT (1)
ANNUAL COSTS:
Debt Service (2) .............••.......
Bond Cost (3)
Fixed O&M (4)
Fuel Cost (5)
$ 7,044,000
604,000
18,000
373,000
2,200,000
TOTAL $ 3,195,000
COST OF POWER (mills/kWh) (6) •••••••••••••••• 50.9
TABLE 5
(1) -$440/kW on line in Sept.-1978 allowing for 1.5% transmission
losses to load center.
(2) -7% -25-year term.
(3) -3% of debt service.
(4) -5.3% of Capital Investment.
(5) -Di~sel fuel at 37.5 ¢/gal. in January 1976, escalated
to late 1978.
(6) -Allowing for 1.5% energy losses to load center and based on
'62,000,000 kWh delivered to load center. (Same energy as
delivered by Green Lake.)
PLANNING
DESIGN
R. W BECK-AND ASSOCIATES
ENGINEERS AND CONSULTANTS
RATES
ANALYSES
EVALUATIONS
MANAGEMENT
200 TOWER BUILDING
SEATILE, WASHINGTON 98101
TElEPHONE 206-622-5000
SEATILE, WASHINGTON
DENVER, COLORADO
PHOENIX, ARIZONA
ORLANDO, flORIDA
COLUMBUS, NEBRASKA
WEUESLEY, MASSACHUSETTS
INDIANAPOLIS, INDIANA
FILE NO_ WW-1521-HG2-MB
3110
~Ir. Fermin Gutierrez, Administrator
City and-Borough of Sitka
Post Office Box 79
Sitka, Alaska 99835
Dear Rocky:
Subject: Re-eva1uation of
Electric Generation Program
September 27, 1976
As you know, in 1974 we prepared an in-depth analysis of Sitka's
Electric System Requirements which resulted in our -recommendation at that time
of a program to satisfy the City's power needs through the year 1990. Speci-
fically, the program recommendations included the Green Lake Hydroelectric
Project initially, followed by an additional unit at Blue Lake and Takatz Lake.
These recommendations have been reinforced by additional analyses we have pro-
vided over the past two years for the Southeast Conference in support of Water
Resources Revolving Loan Fund Legislation and by our work with you over the
same period to develop Green Lake.
In relation to the appropriation of funds for the State Water Re-
sources Revolving Loan Fund, in 1975 the Legislative Budget and Audit Commit-
tee engaged the University of Alaska to conduct a broad study of the electric
power requirements in Alaska and to prepare a report qn the subject. This
report was very much of a broad brush nature because of time and budget limi-
tations, but it did list alternative hydroelectric generation sources for a
number of communities including Sitka. Because of the obvious broad nature
of the data developed for the report, it was inevitable that some of the power
output values and costs would be inconsistent and'we find costs are generally
low compared to those currently being experienced, while the power potentials
are often overstated. In addition we believe that inadequate consideration
was given to the transmission line construction difficulties, reliability and
costs, for a number of the sites. For example, we determined that transmis-
sion line construction costs for some of the projects were calculated assum-
ing that certain other projects, such as Green Lake, had previously been de-
veloped. This artificially shortened the length of transmission line require-
ed for these developments and drastically but inaccurately reduced their cost.
40
36
:= 32
~
"'0 28
>-24
I-
0 20 ~
<t u 16
r ~ 12 <t
W
CL. 8
4
0
140
120
100
:c 80
~
~
60 CDO
I
>-40 l!)
c::: w z w 20
0
LOAD ~ RESERVES-
LOAD GROWTH
TAKATZ LAKE ALTERNATIVE
-I---
'\. ----------
FIGURE 1
I I I
DIESEL 8100 KW
1------
----.. --I-"" .
~ ---~~r ~AKATZ LAKE I ~ ---25,000 KW-4 UNITS
f-N'EW1>IESEL _l.-------
---.r..= ---_oJ f--5,000 KW -2 UNITS
II~XI~_~~~ DIESEL 3100KW
:
1975-76 1976-77 1~7/-71l 1971l-7!!
--
--~
----;-
19;-~;6 976-77 1977·78 1978-79
I
BLUE LAKE
7000
1
KW -i UNIT1S
1979·80 I!JSO-SI MII-82 1982-l!3 19!13-84 1984-8~11985-8611986-87
POWER YEAR
PEAK LOAD AT LOAD CENTER
6% ANNUAL GROWTH RATE
TAKATZ LAKE
93,330,000 kWh
---------I-~
-----
",.--~ .
, DIESEL
BLUE LAKE
44,000,000 kWh
1979·80 19a0-81 1981· 82 1982·83 19;'3-84 1984-85
POWER YEAR
ENERGY -AT LOAD CENTER
6% ANNUAL GROWTH RATE
1985-86
V--
1986-87
I
1987-88 1981!-89 1989-90 19!oO-91
~ ~ ./
...........
I
1987-88 1988-89 1989-9C 1990-91
3=
~
"'0
I
>-....
0 ~
<t
0
~
<t
W
0-
:I:
3:
~
"'0
I
>-C)
0:::
W
Z w
40
36
32
28
24
20
16
1.2
8
4
0
140
120
100
80
60
40
20
LOAD GROWTH
CARBON LAKE ALTERNATIVE
_--I
~ 1---I-DIESEL
FIGURE 2
-,--
~--1""---
V-.--
8~1~?_.~~
LOAD l' RESERrES-'\. ------~ --
---
1~7~-76
..-,..--' I ~ -CARBON LAKE
r--: NEW DIESEL -~ 12,250 KW-2 UNITS
--' f--5,000 KW -2 UNITS
I" EXISTIt:JG DIESEL 3100KW
1
BLUE LAKE
7000
1
KW-f UNIT
1976-7 7 1~77-11l 1978-79 1979-8011980-81 1981-82 1982-83 1983-8_ 198_..fj!> 1985-86 I!:IA6-87 1987-88 1988-11911999-9C ,1990-91
POWER YEAR
PEAK LOAD -AT LOAD CENTER
6% ANNUAL GROWTH RATE
--~ _~--I DIESEL
f..---___ f..-
I
I
L--Yr I 1 1-DIESEL
1 I
I
.1 1 I 1
I CARBON LAKE
43,674,000 kWh i
I i
\
1
I I I I
r_~~~r_-r_--r--+--+--+_--+_-,--~~_r-_r--~---.---:----~
BLUE LAKE i
44,000,000 kWh ----t----il---ir------i
o t:-:19::::7~~7::1rE [-::91=6-=_ 7771:::197=1-=-7:::-8 t:-:19=78:-:_ 7=9t:19=-=79=--80=+19=-=av-:--::-:81+19=-=8:-1--=-=8 2:-1:1::-::96:::-2 -7.83:+1=-=90:::"3--=-8-:-14 =1984:-:-:-8:-1!> CI985=-=_ 8-=-61:-:9=%:-:::-11:-::-7 1:-:197.8 7:-:--~:-::-8 +-:,~-=8Jj~_t:-::-9..l.:-1 :J=-=e-=-9 -~9,)±1:-::~ !o:-::-Ij--:-:-I),
POWER YEAR
ENERGY -AT LOAD CENTER
6% ANN UAL GROWTH RATE
40
36
3: 32
~
"'0 28
I 24 >-....
0 20
·ft
<{
0 16
~ 1.2 c::(
w n. 8
4
0
140
120
100
::r: 80
3:
~
60
"b
I >-40 C> a: w z w 20
0
LOAD GROWTH . FIGURE 3
LAKE DIANA ALTERNATIVE
-~ --I ................. :
NEW DIESEL -,...;..--~
__ -~W-2 U_NI-r:~·. I I
LOAD ~ RESER~ES-"" f--I ~ II --f-----~ DIESEL 8,100 KW
f-~
f----""
I
1975-76 1976-77
---
197~76 976-77
------r I I ____ -NEWDIESE~ -. .. --
.-5,000 KW -2 UNITS
I LAKE DIANA 4;700
EXIST'ING DIESEL 3100KW I UNIT
BLUE LAKE' I
7000
1
KW-f UNI7
1577-78 1978-79 1979-80 1980-81 1981-8Z 198Z-83 1983-84 '984-851,985-861'986-8711987-88
---~
1977-78 1978-79
POWER YEAR
PEAK LOAD -AT LOAD CENTER
6% ANNUAL GROWTH RATE
~~ ~
~
V---DIESEL
---V-I ---.
LAKE DIANA
15,603,000 kWh
BLUE LAKE
44,000,000 kWh
J
1979-80 1960-81 1981-8Z 198z-a3 191:13-84'1984-85
POWER YEAR
ENERGY -AT LOAD CENTER
6% ANNUAL GROWTH RATE
1985-86 1986·87 1987·a8
1
KW
1988-8911989-9oi 19~-91
~ V
~
i
1988·89 1989-90 1990-91
40
36
~ 32
~
"'0 28
I 24 >-t-
O 20 ~
<t
U
16
~ 12
<t w
0-8
4
0
140
120
IPO
:I: 80
~
~
60 ub
I
>-40 C> a: w z w 20
0
LOAD GROWTH FIGURE 4
GREEN LAKE ALTERNATIVE
DIESEL 7100 KW I--~-T-~ l~
__ I .....
LOAD. RESER~ES-", __ >-------1=-l.-----n V--!
~--~--+_-_-4~-----~~--J~~~+--__ -4~--~~~~~~ GREEN-L-A-KE-r---+---4---~--~
~_ NEW DIESEL ~I----15,770 KW-3 UNITS ~~~~I .~~~.~--~r---r---+---~~~~~~~---4----~--4 1-_---~ f--4,000 KW -2 UNITS
r EXISTING DIESEL 3100KW
BLUE LAKE I
~~r---~---+--+---+--+--+~-t 7000
1
KW -, UNI7 --+--+---+--+---1
1975-76 197~71 1971-78 1978-79 1979-801980-81 1981-82 1982-631983-841'984-65 191">5-86 1986-87 1987-88 1988-89 19S9-90119~-91
~ -,
f..--;'--
1975-7E 976-77 1977-78
-
POWER YEAR
PEAK LOAD -AT LOAD CENTER
6% ANNUAL GROWTH RATE
----r-
l--I
~ GREEN
V-r.----
LAKE
1---1---62,817,000 kWh --I.--"""
DIESEL
I
1978-79
BLUE LAKE
44,000,000 kWh
1979-80 19a0-81 1981-82 1982-8j 1~83-84 1984 -85
POWER YEAR
ENERGY -AT LOAD CENTER
6% ANNUAL GROWTH RATE
1985-86
-
986-87 1~7-BB
.~
L.-""""" I
198B-e9 1989-!:IC 1~90-91