HomeMy WebLinkAboutTazimnia Hydroelectric Project Iliamna, Alaska 1998TAZIMINA HYDROELECTRIC PROJECT
ILIAMNA, ALASKA
FINAL TECHNICAL AND CONSTRUCTION COST REPORT
Prepared for:
Iliamna-Newhalen-Nondalton Electric Cooperative
Prepared by:
HDR ALASKA, INC.
2525 "C" Street
Suite 305
Anchorage, AK 99503-2639
August 1998
TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION ...................................................................................................... 1-1
2.0 PROJECT HISTORY ................................................................................................. 2-1
3.0 PROJECT DESCRIPTION ........................................................................................ 3-1
3.1 General. ................................................................................................................ 3-1
3.2 Access Road ........................................................................................................ 3-1
3.3 Stream Channel Control Sill ................................................................................ 3-1
3.4 Intake Structure .................................................................................................... 3-l
3.5 Penstock ............................................................................................................... 3-2
3.6 Powerhouse and Powerhouse Access Shaft.. ....................................................... 3-2
3. 7 Control Building .................................................................................................. 3-3
3.8 Transmission Line ............................................................................................... 3-3
4.0 PERMITS AND LICENSES ..................................................................................... .4-1
5.0 PROJECT MANAGEMENT ..................................................................................... 5-1
5.1 Organization ........................................................................................................ 5-1
6.0 PROJECT COST ........................................................................................................ 6-1
7.0 PROJECT ENERGY PRODUCTION ....................................................................... 7-1
APPENDIX A: Project Construction Photos
APPENDIX B: Selected Project Drawings
August 1998 Tazimina Hydroelectric Project
1.0 INTRODUCTION
The Iliamna-Newhalen-Nondalton Electric Cooperative (INNEC) provides electrical power to
three communities of the same names. These communities are located near the north shore of
Iliamna Lake in south-central Alaska approximately 175 miles southwest of Anchorage. These
communities have a combined population of approximately 600 residents. There is no direct
road connection from these villages to larger population centers. Transportation to the area is
by scheduled air carriers from Anchorage, by barge from Naknek via the Kvichak River or by a
combination of barge from Homer, truck over a World War II mountain road and barge across
Lake Iliamna from Pile Bay to Iliamna.
Electric power has been generated by INNEC since 1983 using diesel generators located in the
community of Newhalen. Fuel for these generators was transported up the Kvichak River, an
important salmon river, and across Iliamna Lake. In dry years the river is low and fuel is flown
into Iliamna and then trucked five miles into Newhalen. The cost, difficult logistics and
potential spill hazard of this fuel was a primary reason for development of hydroelectric power
in this area.
A hydroelectric project was constructed for these communities, starting in the spring of 1996
and ending in the spring of 1998. The project site is on the Tazimina River about 12 miles
northeast of Iliamna Lake. The Tazimina River flows west from the Aleutian Range. The
project site is at Tazimina Falls about 9 miles upstream of the confluence ofthe Tazimina River
and the Newhalen River. The project has an installed capacity of 824 kilowatts (kW) and is
expandable to 1.5 megawatts (MW). The project is run-of-the-river (no storage) and uses the
approximately 100 feet of natural head provided by the falls. The project features include a
channel control sill, intake structure, penstock, underground powerhouse, tailrace, surface
control building, buried transmission line and communication cable, and access road.
The intake is located approximately 250 feet upstream of the falls. The channel control sill is
located immediately adjacent to the intake. From the intake, flow to the turbines is directed
through a 60-inch-diameter penstock. The penstock runs 300 feet to the underground
powerhouse. The powerhouse is 120 feet below ground adjacent to the river and is connected
to the surface via an elevator in a 26-foot-diameter shaft. The powerhouse contains two
turbines, generators, and auxiliary equipment. Water is discharged into the Tazimina River at
the base of the falls through an 8-foot-high horseshoe shaped tailrace tunnel. A control
building is located at the top of the shaft and contains all communications, controls and
HVAC equipment. The intake, penstock, powerhouse cavern and tailrace are designed and
configured to accommodate doubling the capacity to 1.5 MW in the future.
An access road, 6.7 miles long, leads from the existing Newhalen-Nondalton Road around
the northern end of Alexcy Lake to the project site. A transmission line and a
communications cable are buried along the road edge. The transmission line is tied into the
existing transmission line that runs between Newhalen and Nondalton.
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2.0 PROJECT HISTORY
The idea of developing hydropower in the Tazimina River area dates back to as early as 1909,
when a U.S. Geological Survey Report concluded that many of the surrounding streams
"could be used for water power whenever the development of the region creates a demand for
it."
Over the past 18 years, more extensive investigations and environmental studies have
analyzed potential hydropower alternatives on the Tazimina River. Federal and state
agencies investigated the project in the 1970s and early 1980s. In 1988, INNEC began
pursuing the Tazimina hydroelectric development as an alternative to diesel fuel. The
following narrative presents some of the more significant steps in the development of the
Tazimina project.
1979 The U.S. Department of Energy completed "Bristol Bay Energy and Electric Power
Potential," (BBRPP) which explored numerous energy sources for the region,
including geothermal, hydropower, coal, wind, and solar energy. Power schemes
explored included diesel, gas turbine, steam turbine, wind-electric, and hydroelectric
generating units. The report found hydroelectric power to be the most viable source
of energy to supplement or replace diesel in the Bristol Bay region. The study
identified a variety of potential small-scale subregional hydroelectric projects to serve
the area's many villages and a regional dam project at Tazimina Lake on the Tazimina
River.
1980 The Alaska Power Authority (APA) completed a reconnaissance study to further
investigate some of the recommended projects, including the one at Tazimina Lake.
The report strongly recommended the immediate development of the Tazimina Lake
project, to be joined with the Naknek/King Salmon and Dillingham utilities.
1982 The AP A completed the "Bristol Bay Regional Power Plan Interim Feasibility
Assessment", which assessed the technical, economic, and environmental aspects of
various hydroelectric alternatives for the region. Based on economic feasibility
considerations, this study ultimately recommended construction of a 16 MW dam
project on the Newhalen River. It ranked a regional Tazimina dam project second and
a subregional run-of-the-river Tazimina project at Tazimina Falls for Iliamna,
Newhalen, and Nondalton fifth out of 21 power plan scenarios. In a 1983 economic
update to this report, the Newhalen dam continued to rank first, but the subregional
Tazimina run-of-the-river project rose to second.
An environmental impact evaluation in the BBRPP ranked the subregional Tazimina
run-of-the-river project first. Resource agency comments on the BBRPP, as well as
policies in regional planning documents, discouraged projects involving dams on
anadromous fish streams due to impacts to fisheries. Fish studies for the Newhalen
project were undertaken from 1982 to 1985.
August 1998 Tazimina Hydroelectric Project
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1985 The AP A conducted an updated economic evaluation of several promtsmg
alternatives identified in the BBRPP. The APA determined that the Newhalen project
and other large regional projects were no longer economical due to declining oil
prices, large capital costs, and low electrical loads in the region. This evaluation
indicated that the subregional Tazimina project was feasible, a conclusion that was
further substantiated in the APA's "Findings and Recommendations" dated February
1986.
1987 The APA completed a feasibility report for a variety of run-of-the-river development
alternatives projects at Tazimina Falls (Stone and Webster Engineering Corporation).
Concludes 700 kW project with underground powerhouse would have a capital cost of
$8 million and would have a present worth cost compared to diesel power of $1.06.
1991 Economic analysis updated by HDR Engineering. Estimates 700 kW project with
underground powerhouse would have a capital cost of $9.4 million and would have a
present worth cost compared to diesel power of $1.32.
1992 Initial Consultation Document filed with the Federal Energy Regulatory Commission
for application for a license for the project.
1994 Engineering Review and Constructibility Study of the Tazimina Hydroelectric Project.
The purpose of this work was to review the project configuration previously developed
for the project and develop alternative layouts for the project. Estimates 700 kW project
with underground powerhouse would have a capital cost of $10.4 million.
1996 Final design of project by HDR Alaska.
1996 Construction Awarded to Wilder Construction Company.
1997 Start of limited commercial operation
1998 Construction ofproject completed.
August 1998 Tazimina Hydroelectric Project
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3.0 PROJECT DESCRIPTION
3.1 General
Main features of the proposed project include an access road, stream channel control sill, intake
structure, buried steel penstock, underground powerhouse, control building and underground
transmission line. Plan and section drawings of these features are shown in Appendix B.
3.2 Access Road
Access to the project site is via a 6.7-mile gravel road. The access road extends from the
Newhalen-Nondalton Road, around the north end of Alexcy Lake and on to the project site
along the left bank of the Tazimina River looking downstream. The road is a limited access
road of single lane construction, 16' wide.
3.3 Stream Channel Control Sill
A linear concrete sill is constructed across the right side of the river, opposite the intake
structure. The purpose ofthe sill is to prevent degradation of the streambed, and to help divert
streamflow to the intake during periods of low flow. The sill is 144 feet in length and is
constructed of pre-cast concrete blocks. The blocks are trapezoidal in section to provide
stability against flowing water. Block dimensions are 2.5 feet high by 8 feet long, with a 2-foot
top width and 5-foot bottom width. The blocks are fastened to the rock streambed with steel
rock bolts. The top of the sill is visible above the water at low flows, but it is totally submerged
during spring and summer at higher flow periods.
3.4 Intake Structure
Because there is no dam, the problem of diverting 110 cfs (ultimately 220 cfs in the future) to
the intake presents a design challenge, and the 170-foot-wide river channel makes it difficult to
attract a large percentage of the streamflow to the intake during low flow periods.
Compounding the problem is the potential of ice blocking the intake during the low flow
period.
The intake structure is located on the left bank approximately 250 feet upstream of the top of
the falls. The function ofthe intake is to withdraw 110 cfs from the river, the hydraulic capacity
of the units, during the low flow period between January and April. The location, dimensions,
and elevations of the intake were designed based on a physical scale model constructed in a
hydraulics laboratory. This modeling optimized location of the intake to attract a large
percentage of the stream flow from the 170-foot-wide river channel to the intake during low
flow periods.
August 1998 Tazimina Hydroelectric Project
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The concrete intake structure is constructed in the bedrock bank of the river. There is a 4-foot-
deep sump in front of the trashrack to trap bedload. The trashrack is designed for a maximum
of 1.5 feet per second approach velocity. If the capacity of the power plant is eventually
doubled in size, the increased flow will result in an approach velocity of 3 fps without
increasing the trashrack size. This is the recommended maximum velocity for manual cleaning.
The trashrack is set 2 feet below minimum water surface elevation to minimize entrainment of
floating material. The trashrack is constructed of HOPE to prevent the adhesion of frazil ice.
Sensors are installed to detect differential pressures across the trashrack in order to determine if
there is trashrack blockage. Stoplog slots and concrete stoplogs are provided to allow
dewatering of the intake box. The intake box expands the flow area reducing the water
velocities to less than 1-foot per second allowing coarse sediment to drop out of suspension.
This sediment is collected in a trap at the bottom of the intake and is pumped out of the intake
with a sluice pump. The walls of the intake box are provided with heat trace to prevent freezing
ofthe intake box if the project is shut down during winter.
The intake vault houses the controls, penstock shutoff valve, and miscellaneous equipment.
The shutoff valve is a 60-inch-diameter electrically operated butterfly valve.
3.5 Penstock
From the intake, flow to the turbines is conveyed via a 60-inch buried welded steel penstock.
The penstock diameter is sized to convey 220 cfs, or double the initial hydraulic capacity of the
power plant. Overall penstock length is 300 feet. The penstock is buried in a trench cut in the
native rock for 140 feet and is grouted in place within a tunnel for 40 feet. The remainder of the
penstock is vertical and is within the powerhouse access shaft. Vent pipes are located
immediately downstream of the valve and at the top of the vertical section to provide air release
and vacuum and surge protection.
3.6 Powerhouse and Powerhouse Access Shaft
The powerhouse is an underground structure excavated into the native rock to the left of the
base ofthe falls. The powerhouse is 32 by 58 feet in plan view and 16 feet high. The generator
floor is set at elevation 483 feet, about 13 feet above the streambed at the base of the falls. This
design accommodates a tailwater for the draft tubes and prevents backwater during winter icing
conditions. The powerhouse is connected to the surface by a 26-foot-diameter vertical shaft.
Within the vertical shaft are the penstock, fresh-air ducts, communications and power cables
and an elevator. The walls and ceiling of the powerhouse and the walls of the shaft are
reinforced with patterned rockbolts and shotcrete. Drainage fabric is placed between the rock
and the shotcrete to intercept ground water.
The powerhouse contains two horizontal Francis turbines, generators, and auxiliary equipment.
The turbines are rated at 412-k W at a design flow and head on each unit of 55 cfs and 96 feet,
respectively. An 8-foot-wide draft tube pit serving both units is excavated below the cavern
floor. Tailwater level is controlled by a control sill constructed within the tailrace. A concrete
August 1998 Tazimina Hydroelectric Project
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floor is constructed within the cavern and over the draft tube pit and tailrace channel. A
primary sump pump is located within the cavern and discharges to the tailrace. A backup sump
pump discharges to the surface. In conjunction with the turbine generating units, the
powerhouse also accommodates a 540 kW load bank, which is used for supplemental load to
keep the turbines at or near peak efficiency throughout system load swings.
The powerhouse is sized and configured to accommodate doubling the plant capacity to
approximately 1500 kW in the future. New turbines and generators would replace the units
initially installed.
3. 7 Control Building
A 36-foot by 46-foot control building is constructed on top of the vertical shaft. The building
houses the controls, elevator, batteries, standby diesel generator, HV AC system and an office.
It also provides access to the shaft for equipment removal and installation. The building is steel
frame construction, with insulated steel panels for the roof and walls.
3.8 Transmission Line
The transmission line is 6. 7 miles long and operates at 7200/ 124 70 volts. The line is buried and
follows the new access road alignment. The new transmission line is buried 25 kV 260 mil
EPR insulated cable with concentric neutral and matches the cable used throughout the INNEC
system. A transformer at the powerhouse end steps up the 480V generation voltage to
7200/l2470V. A tap changer is provided to allow some adjustment in transmission voltage to
best match the system at the tie-in point. A 25-pair communications cable is installed along
with the transmission line to provide voice and control circuits for the plant, as well as manual-
remote control of the main circuit switch.
August 1998 Tazimina Hydroelectric Project
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TABLE 3-1
SUMMARY OF PROJECT FEATURES
PROJECT FEATURE DESCRIPTION
Name of Project Tazimina River Hydroelectric Project, FERC Number 11316
Project Location Section 24, Range 32 West, Township 3 South, Seward Meridian. 12 miles
northeast of the community of Iliamna in South-central Alaska. Approximate
latitude 59°54' and longitude 154°42'.
Intake Run-of-the-river shoreline intake 250 feet upstream of the falls at elevation 570
feet msl.
Reservoir None. Run-of-the-river project.
Penstock Total Length: 300 feet
Diameter: 60 inches
Material: Lined and coated steel
Components: All buried pipe to the powerhouse
Tailrace 8 foot horseshoe tunnel to base of Tazimina Falls
Powerhouse Size: 32 feet by 58 feet
Number of Units: 2
Type ofTurbines: Horizontal Francis
Turbine Rating: Flow: 55 cfs each unit; I I 0 cfs total
Gross Head: 92 feet
Generator Rating: 412 kW each unit, 824 total, expandable to 1500 kW
Load Bank: 540 kW Max.
Transmission Line Voltage: 7.2112.47 kV
Length: 6.7 miles
Type: Underground
Average Annual Energy Initial Load: 6,030,000 kWh per year (Energy Production at Capacity)
Production
August 1998 Tazimina Hydroelectric Project
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4.0 PERMITS AND LICENSES
Land issues posed an initial hurdle for the Tazimina Hydroelectric Project. The project site
surface estate was owned by Iliamna Natives Limited (INL), a Native village corporation
holding land in trust for local Alaska Natives. The subsurface lands (gravel) are owned by a
Native regional corporation. The land also lies in an in-holding within Lake Clark National
Preserve, where National Park Service (NPS) jurisdiction normally applies. Submerged lands
in Alaska, such as the bed of the Tazimina River, are typically owned by the state, although
in this case both the state and INL claimed ownership of the river bed. Because of the
complicated jurisdiction, a considerable amount of time was spent gaining approval for the
different components of the project. This approval process lasted well into the project
development stage. Representatives from Native groups, local organizations, and local, state,
and federal government worked together to resolve these complex land and water issues.
Another hurdle appeared during the project's inception in the early 1980s: licensing by the
Federal Energy Regulatory Commission (FERC). FERC jurisdiction had originally not been
exerted and then was later imposed based on the potential for impacts to salmon. Later, a
section of the Energy Policy Act of 1992 exempted the Tazimina Hydroelectric Project from
certain FERC licensing requirements. After further discussions between regulators, INNEC,
and HDR, FERC staff ruled that the project still required compliance with the National
Environmental Policy Act (NEPA). An environmental assessment would be necessary.
Regulatory agencies raised additional environmental concerns, such as: 1) Would the project
intake entrain resident fish, thereby serving to permanently "fish" the river reach above the
falls? 2) How would gas supersaturation at the tailrace affect fish? 3) How would sensitive
plants and endangered peregrine falcons that might live in the region be protected from
project impacts? 4) Would an access road in this relatively roadless part of Alaska result in
increased vehicle traffic in and around a national park?
Seeking to answer these questions, INNEC hired HDR Alaska to conduct environmental
studies. Field reconnaissance and research produced these findings:
1. The project's intake would not adversely affect fish. Summer and winter fish
surveys above the falls confirmed that the 914-m (3,000-ft) stretch of river
above the falls was marginal fish habitat. Approximately 80 fish (Dolly
Varden and sculpin) were found during the rigorous yearlong sampling
program. A scale model was constructed that demonstrated that sweeping
velocities in front of the intake would limit the potential for fish entrainment.
2. Tazimina Falls already produced natural, substantial but very temporary gas
supersaturation at the foot of the falls, and salmon spawning occurred no
closer than 2.4 km ( 1.5 mi) downstream of the falls.
3. Field surveys ofthe rock cliffs in the canyon downstream of the falls found no
threatened or endangered species.
August 1998 Tazimina Hydroelectric Project
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4. The corporation holding title to the land agreed to limit access on the road.
The route of the access road would avoid any creek crossings or wetland areas.
FERC issued the environmental assessment for the project on July 28, 1995.
Despite these findings, another snag occurred: FERC decided not to issue an exemption for
the project until receiving a determination that it was consistent with the State of Alaska's
coastal management program regulations. The state's Division of Governmental
Coordination (DGC), the agency capable of making that determination, wanted to see the
project's final design plans before making this ruling. Release of funds for final design was
contingent on the grant of the exemption.
Fortunately, HDR staff brought to light an obscure legality that appeared to allow DGC to
review the project in phases. When INNEC and HDR secured a phase one review from
DGC, FERC responded by issuing an exemption order for the Tazimina project in September
1995.
August 1998 Tazimina Hydroelectric Project
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5.0 PROJECT MANAGEMENT
5.1 Organization
This section identifies the key construction management personnel and chain of command
used during the administration of the project, as well as quality control and inspection
responsibilities. The attached organization chart shows the key project team members
involved with project quality control and engineering design and the related chain of
command. A description of each member's role and responsibilities follows in this section.
The scale and location of this project is such that it did not require, or warrant, full-time, on-
site representation from all members of the project team. Only one or two of the members
(tield engineers) of the team were required to work full-time on-site to oversee project
construction and to perform the required field material tests. On an as-needed basis, the full-
time field engineers were supplemented by the other members of the team as the construction
and the schedule dictated.
August 1998 Ta.zimina Hydroelectric Project
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Tazimina Hydroelectric Project
Organization Chart
Exemptee
Brent Petrie
INNEC
I I l
Schedule Control Accounting Project Manager Mark Dalton
Bob Tripp Steve Wells Duane Hippe, P.E. Contract Manager
MAC SW&A HDR HDR
Civil Engineer Geotechnical Support
Paul Berkshire, P .E. As needed
Bob Butera, P.E.
HDR
Mechanical Engineer
Michael Haynes, P.E. 1 1
HDR Jim Rooney Gregg Corbin
Pete Hardcastle HDR
R&M Consultants Rich Linamen
Lache! & Associates
Electrical Engineer
Ernest Swanson, P.E.
HDR Field Engineer
Joe Wagner
HDR
Environmental Coordinato
Mark Dalton
HDR
I
Asst. Field Engineer Asst. Field Engineer Asst. Field Engineer Asst. Field Engineer
Don Dodds, Ph.D. Jon Hughes Dave Fowler Leonard Palmer
HDR HDR HDR HDR
Construction Contractors Materials Testing Lab
R&M Consultants
Turbine/Generator Supplie General Construction
Cliff Maim, P.E. Contractor
Burke Electric Clif Olmstead
Wilder Construction
AugLL<>t 1998 Taz.imina Hydroelectric Prclject
5-2
Key Personnel for Qualitv Control of the Tazimina Hydroelectric Project
Brent Petrie, General Manager, INNEC As the owner's representative, Mr. Petrie had
overall responsibility for the project, particularly the engagement of project personnel in
quality control activities associated with the Tazimina project. Mr. Petrie had primary
responsibility for project contract issues. Mr. Petrie was in daily contact with key project
staff to ensure that project personnel are adequately coordinated and directed. Mr. Petrie
worked directly with the affected parties on land issues, particularly issues dealing with
access to and use of private and public lands for the completion of the project.
Duane Hippe, P.E., Project Manager Mr. Hippe managed the Tazimina Hydroelectric
project construction and reviewed the work and decisions of the design engineer and the field
engineer. He was responsible for coordination of construction and design items with the
project owner, ll\TNEC, and communication with the contractor. Mr. Hippe scheduled and
coordinated field inspections and off-site materials testing. Mr. Hippe also made routine site
visits to the project site. Mr. Hippe worked with Mark Dalton on oversight of project
contract issues with the project owner.
Paul Berkshire, P.E., Design Engineer Mr. Berkshire had pnmary responsibility for
development of the civil drawings.
Mike Haynes, M.E., Design Engineer Mr. Haynes had primary responsibility for
development of the mechanical drawings, review of mechanical shop drawings and
coordination of the turbine, generator and controls procurement and installation.
Ernie Swanson, E.E., Design Engineer Mr. Swanson had primary responsibility for
development of the electrical drawings, review of electrical submittals and field assistance
inspection of turbine, generator and controls installation.
Bob Butera, P.E., Design Engineer Mr. Butera was responsible for hydrologic and road
design and review of shop drawings and test results to ensure that the project was being
constructed according to the design specifications and intent. Mr. Butera communicated
regularly with the field engineer to monitor progress and to provide technical support in
resolving engineering issues.
Joe Wagner, Field Inspector Mr. Wagner was the on-site field inspector for the duration of
the project. Mr. Wagner was supported in the field by an assistant field engineer(s) during
periods of extensive construction activity and rock work. During the rock tunneling work, a
blasting supervisor was retained on-site to oversee the tunneling work, especially blasting
work. As field engineer. Mr. Wagner was responsible for ensuring that all aspects of the
construction documents are being fulfilled.
August 1998 Tazimina Hydroelect'lic PrQject
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Mark Dalton, Environmental Coordinator Mr. Dalton was responsible for reviewing and
monitoring project construction to ensure compliance with all the FERC license compliance
articles and project permit stipulations. He specifically documented compliance with the
terms and conditions presented in the Project's erosion and sedimentation control plan and
monitor construction activities that could potentially impact the Tazimina River and the
privately owned lands. Mr. Dalton acted as the liaison with FERC staff and local and state
permitting authorities. Mr. Dalton handled overall contract issues.
Bob Tripp, Scheduling Coordinator Mr. Tripp was responsible for schedule control and
compliance. Mr. Tripp tracked project progress. Mr. Tripp's Company also assisted with
review and settlement of potential claims.
Steve Wells, Project Accounting Mr. Wells had overall responsibility for tracking project
costs and preparing accounting reports for the state and federal grants.
August 1998 Tazimina Hydroelectric Project
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6.0 PROJECT COST
An estimate of probable construction cost was prepared for the project. The estimated direct
construction cost of the project was $6,887,000. Total project development cost, including
engineering services, owner costs, contingencies and escalation was estimated to be
$10,359,000 in 1994. In February 1997 the formal estimate to complete was $11,904,000.
Bids for the turbine, generator and controls were received from three vendors. The winning bid
was received from Burke Electric for $1,425,334. Change orders for $77,027 were processed
for a total cost of $1 ,502,361.
Bids for the general construction were received from three contractors. The winning bid was
received from Wilder construction for $7,248,700. Deductive alternates for a lessor quality
road totaled [$673,520]. Total contract cost was $6,331,154 excluding engineer directed items.
Change orders totaling $16AOO were processed. The final cost for the general construction
was $6,347,554.
Costs for FERC licensing, NEP A, geotechnical investigations, topographic surveying, hydraulic
modeling, engineering design, permitting and construction management and administration
totaled approximately $3,650,000. Land Acquisition and interest during construction totaled
approximately $210,000.
Total cost ofthe project was $11,714,500.
Funding for the project came from the following sources:
State of Alaska Grant through DCRA
Federal Grant Administered by USDOE
Financing
August 1998
6-1
$5,000,000
$3,380,000
$3,334,500
Tazimina Hydroelectric Project
7.0 PROJECT ENERGY PRODUCTION
The rated generator nameplate capacity ofthe units is 824 kW. This equates to a theoretical full
load capability of approximately 800 kW at maximum net head. (Note: Unit performance
testing indicated a maximum demonstrated output of 804 kW, as measured on the generator
low-side bus.) Current peak load in the INNEC system is about 575 kW in summer and 420 kW
in winter. About 110 cubic teet per second of water is required to produce full turbine output.
There are 5-112 years of daily flow records on the Tazimina River at the falls. During this
period, the lowest recorded river flow was 140 cfs. Although it is likely that flows may
occasionally drop below 140 cfs, it is reasonable to assume that 110 cfs is available at most
times for diversion except during short periods in the late winter months. If this is the case, full
load output should be available at most times from the units, if necessary. In reality, the units
are operated to follow the f.t\.'NEC system load. It appears that at least in the near term,
sufficient energy is generated by the hydro facility to carry l 00% of the INNEC load, except
during very low river flow periods or during hydro plant outages.
An estimate of the maximum theoretical energy generation from the project was made. The
daily flows at the diversion site for the five years of record, and project information (such as
pipe length, diameter, headwater and tailwater elevation, turbine and generator efficiency
curves, and other system losses) were input into a model to calculate energy production for each
day of the period of record.
The model was run for two cases; a) using the constructed project arrangement with two, units
with a total diversion of 110 cfs, and; b) the same arrangement using two approximately 750
kW units and a total diverted flow of 220 cfs (future case). Results show that the maximum
theoretical generation from the proposed arrangement is about 6,030,000 kWh per year. In the
future, increasing diversion to 220 cfs and replacing the turbines with two 750 kW units could
provide up to l 0,800,000 kWh per year. Current INNEC system load is approximately
2,200,000 kWh per year.
August 1998 Tazimina Hydroelectric Project
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APPENDIX A
PROJECT CONSTRUCTION PHOTOS
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Project site, August 1996.
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Intake construction, August 1996.
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Penstock placement,
September 1996.
Intake construction, September 1996.
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Completed intake with sill in river,
May 1997.
Face of intake,
October 1996.
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Shaft pattern rock bolting, August 1996.
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Underground powerhouse construction, November 1996.
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Control building,
May 1997.
Arrival of turbine and bifurcation, September 1996.
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-Completed diversion sill, Apri11997.
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-Tailrace tunnel, December 1996.
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APPENDIXB -
SELECTED PROJECT DRAWINGS