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HomeMy WebLinkAbout07242019 PACAB - Laydown - Lowell Creek Hydro CONCEPT DESIGN AND ECONOMIC EVALUATION OF LOWELL CREEK HYDRO PROJECT TO PROVIDE CLEAN GRID ELECTRICITY FOR CITY OF SEWARD, ALASKA I L.. f F�u J r � I n , FINAL REPORT COMPLETED JUNE 21, 2019 BY ANDY BAKER, PE "Celebrate the power of nature"TM ... with YourCleanEnergy LLc ■ 308 G Street#215,Anchorage AK 99501 907-350-2084 www.yourcleanenergy.us TABLE OF CONTENTS SCOPE OF CONCEPT DESIGN AND ECONOMIC EVALUATION.......................................................................................................3 LIMITATION IN SCOPE OF THIS CONCEPT DESIGN AND ECONOMIC EVALUATION EFFORT.....................................................3 SUMMARY AND CONCLUSIONS........................................................................................................................................................4 SUMMARY AND CONCLUSIONS(CONT'D)........................................................................................................................................5 INTRODUCTION...................................................................................................................................................................................6 ANTICIPATED BENEFITS TO THE CITY FROM LOWELL CREEK HYDRO PROJECT......................................................................6 COST OF POWER FOR CITY OF SEWARD-2019.............................................................................................................................7 EXISTING HYDRO-ELECTRIC FACILITIES.........................................................................................................................................7 HYDROLOGY.......................................................................................................................................................................................8 PROJECTED FLOWS BASED ON EXISTING DATA...........................................................................................................................8 PROJECTED FLOWS BASED ON EXISTING DATA(CONT'D)..........................................................................................................9 RUN OF RIVER COANDA STYLE INTAKE WITH BURIED INFILTRATION GALLERY.....................................................................10 RUN OF RIVER COANDA STYLE INTAKE WITH BURIED INFILTRATION GALLERY(CONT'D)....................................................11 PENSTOCK MATERIAL SELECTION................................................................................................................................................11 HYDRO-ELECTRIC ENERGY PRODUCTION....................................................................................................................................12 ESTIMATED HYDRO-ELECTRIC ENERGY BASED ON PROJECTED STREAM FLOWS................................................................12 HYDRO-ELECTRIC TURBINE EQUIPMENT SELECTION.................................................................................................................13 TURBINE HOUSE CONCEPT DESIGN..............................................................................................................................................14 TURBINE HOUSE CONCEPT DESIGN(CONT'D)..............................................................................................................................15 TURBINE HOUSE CONCEPT DESIGN(CONT'D)..............................................................................................................................16 EVALUATING HYDRO PROJECT COSTS VS BENEFITS.................................................................................................................17 OPINION OF PROBABLE CAPITAL COSTS—PROPOSED HYDRO-ELECTRIC PROJECT-2019.................................................17 OPINION OF PROBABLE PROJECT COST—PROPOSED HYDRO-ELECTRIC PROJECT-2019..................................................18 ESTIMATION OF PROBABLE ANNUAL COSTS—HYDRO-ELECTRIC FACILITY-2019................................................................19 OPERATIONS.....................................................................................................................................................................................19 WATERRIGHTS.................................................................................................................................................................................20 ■ "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 3 OF 20 SCOPE OF CONCEPT DESIGN AND ECONOMIC EVALUATION 1. Development of concept designs to support the installation of a run of river small hydro-electric project with intake at elevation @460 ft along Lowell Creek; and pelton wheel turbine near sea level to generate grid power in Seward,Alaska.The concept design and associated economic evaluation will be based on addressing the following: 2. How to safely divert year-round stream flow into a settling / de-sander tank at elevation 460 ft without bringing in the bed load sediment during flood events. The solution may be in part the installation of infiltration gallery french drain piping that collects flow from under the stream bed, similar to what Alaska SeaLife Center does for water collection at the base of Bear Mountain along Lowell Point Road. A self-cleaning coanda style screen in the stream channel may also be part of the intake solution. A de-sander settling tank could catch most of the fines that make it through, and keep the erosion of stainless steel pelton wheel buckets to a minimum. There will be a need to weld re-build the buckets periodically and spare pelton wheels must be available for installation as part of ongoing maintenance. 3. How to route the buried penstock (range of 36 to 48 inch diameter)from the base of Lowell Creek Canyon to a generator station location at shoreline that makes good sense. The penstock could be routed straight down Jefferson Street and be sited in the Waterfront Park campground area (creates a conflict of land use and continuous noise issue); or the penstock could gradually bend 90 degrees to the south to a generator plant adjacent to Alaska SeaLife Center(may require some tunneling but probably a more suitable location to generate power). 4. How to integrate the small hydro generation into the City of Seward electric grid in a simple and cost effective manner; how to design a hydro generation system that will impart the lowest O&M cost and highest reliability, stability, and safety to the City. Address the benefits and liabilities of operating the hydro when the City is isolated from Chugach Electric Association (CEA)transmission and is operating diesel generators. Address the benefits and liabilities of shutting down the hydro plant when the stream reaches pre-flood and flood stages; and re-starting the hydro plant once the flooding subsides. 5. Based on the concept design above, update the Economic Evaluation first developed by YourCleanEnergy (YCE) in 2007 to determine a Opinion of Probable Capital Cost of the project; opinion of what O&M costs to operate the hydro plant could be; and what the cost of power would be to the City once the hydro plant is built and operating, assuming a conventional mix of grants, bonding, sales revenue and other debt service structures. 6. Produce deliverable Economic Evaluation report in PDF format that includes above items, schematics, graphs, technical information, cost estimates, etc, in a simple easy to read format. 7. Make one public presentation in Seward to communicate the results of the evaluation. LIMITATION IN SCOPE OF THIS CONCEPT DESIGN AND ECONOMIC EVALUATION EFFORT It is understood that the above effort is at a concept level only and if project feasibility is identified, would be followed up by a more detailed engineering evaluation; exploration of the Federal Energy Regulatory Commission (FERC) permit path and costs; addressing the costs and path of navigation with current Army Corps (ACOE)efforts regarding the Lowell Canyon Tunnel;the costs and paths of securing other applicable state and federal permits; the cost implication of integration of the hydro power with CEA who currently supplies power to Seward via long distance transmission; and other relevant factors that may impact a hydro project operating year round on Lowell Creek. 0 "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 4 OF 20 SUMMARY AND CONCLUSIONS A concept design for a small hydro-electric system has been developed for Lowell Creek in Seward, and economic evaluation of that system has been completed. This effort was made because of the rapidly increasing cost of fossil fuel electricity generation available to Seward; and because new technologies and approaches are available that will increase the cost effectiveness of both design and construction of such a system. It will be necessary for the City to begin an effort to gage the stream flow in the upper area of Lowell Canyon (elevation 460 ft) since very minimal historic or recent data is available for this resource in that location. Several years of flow data will be needed to confirm the resource for DNR and FERC permits, and to fine tune the concept design and economic evaluation to reflect the anticipated stream flows. The primary goal of the evaluation presented herein is to identify a small hydro-electric system that will reliably collect stream flow year-round at elevation 460 feet up the Lowell Creek Canyon; transport that flow down the canyon and thru City streets in a buried penstock to a turbine house close to sea level; and produce affordable, reliable and safe electricity from a spinning turbine with a grid-tied synchronous generator. Two alternative locations for the low elevation turbine house were considered. Alternative A. The primary and least complex alternative is to route the penstock from the intake straight down the right of way of Lowell Canyon Road and Jefferson Street, and locate the turbine house at elevation 26 feet in the existing 100 foot wide ROW in the Waterfront Park area.The stream intake would be designed for a maximum of 60 CFS and consist of a surface flow diversion and coanda style surface screens. An infiltration gallery upstream of the diversion with below grade French drain collectors would be included to collect flow during low flow periods in winter. The penstock would be 42" diameter, 7,200 foot length, with the upper portion HDPE material, and the lower portion welded steel. In Lowell Canyon, the penstock would be buried below a benched gravel access road routed along the north side of the canyon, with sheet piling and large rip rap to protect against seasonal flooding. The penstock would pass thru the north end of the existing concrete diversion dam, adjacent to the existing Marathon Creek hydro plant. The penstock would then be routed down the right of way of Lowell Canyon Road and Jefferson Street to a low profile turbine house located adjacent to existing seasonal RV and tent camping areas. Electricity from the turbine generator would be synchronized with the City's 12.5 KV distribution system; and connected to the grid at a power pole across Ballaine Avenue. The tail race of the turbine house would allow flow to drain from the turbine into a buried concrete box culvert tailrace extending to a submerged outlet to be located adjacent to the historic wood flume at beach elevation. Alternative B. A second option for the turbine house location alternative was adjacent to the Alaska SeaLife Center (ASLC) on University of Alaska Fairbanks (UAF) property. This alternative was not pursued to concept design or economic evaluation. It proved to be very complicated and problematic due to: multiple sharp bends in penstock alignment required; crowded utility corridors in narrow streets and alleys; and acquisition of University property and associated easements that would be required for both the penstock and turbine house. It is the preference of the City to keep as much of the proposed hydro-electric system within City land and within City R.O.W. as possible; this alternative does not afford that preference. Alternative A was developed to the level of concept design and economic evaluation.This concept suggests a maximum turbine generator capacity of 1.8 MW (@60 CFS flow); and estimated annual electricity production of 9,202,000 KWH. This would satisfy approximately 15% of the City's current grid electricity needs. The hydro-electric system would cost approximately $17.9 million to build (in 2019 dollars); and produce electricity at about$0.1139 per KWH (if built in 2019). The stream intake and upper portion of the penstock would be constructed with permits on DNR land. Access to the upper portion of the system would be by new gravel road on the north side of the canyon. The lower portion of the penstock, the turbine house, and the tailrace would be constructed on City land. Electricity would flow directly into the City distribution system without transmission line loss. The turbine house would be easily accessed for monitoring and maintenance via the existing Waterfront Park access roads. Waste heat from the turbine house could be used as valuable source energy for the ground source heat pump system planned for the City Library. Extra expense and design consideration will be required to prevent noise from the turbine house and tailrace from disturbing summer campground use. This concept can be further refined and improved once a stream flow gage is installed in the upper canyon and monitored for at least two years. 0 "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 5 OF 20 SUMMARY AND CONCLUSIONS (CONT'D) For the purpose of this concept level evaluation, a simplified schematic of Alternative A with the proposed stream intake, penstock, and turbine house with outfall to Resurrection Bay is shown below: I ;a a rr.IP(mnU,t RROIIOSE TURBINE OUI$E, A ^ PROPOSED WITH O TFAL 4 "' DIAMETER PROPOSED PENSTOCK S w iff( RUN-OF-RIVER INTAKE , NR As� CITY LAND NIAN ..... �w.� I I r rr yr w:w +yr yr w:w �y,9 .ur...... ............e ...................... .. yr yr s+.r r.................................................. .. ..e m�a NWRVdfWAVAM 0 NVAMrOIN NW ,N OaMRGW 4 lN6d NWNyfa!yAfN f 10 Alternative A: This design concept affords the straightest penstock alignment and greatest elevation drop (from 460 ft elevation at stream diversion to 27 ft elevation at turbine house). Red circles on the map indicate the location of water rights already secured by the City of Seward. 0 "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 6 OF 20 INTRODUCTION On September 11, 2018, the City of Seward secured the services of YourCleanEnergy(YCE)to prepare a Concept Design and Economic Evaluation to support the installation of a run of river small hydro-electric project with intake at elevation @460 ft along Lowell Creek; and a pelton wheel turbine generator near sea level to generate grid power in Seward, Alaska. On February 29, 2019 the City of Seward secured the services of YCE for engineering time anticipated with on-going coordinating for compliance with following state/federal agencies: Alaska Department of Natural Resources (DNR); Alaska Department of Fish & Game (ADF&G); Army Corps of Engineers (ACOE); and Federal Energy Resource Commission (FERC). The coordination is required for initial permits, meetings and information exchange to support the development of a small hydro-electric system on Lowell Creek for the City. This coordination time effort is additional to the YCE proposal of September 11, 2018 to perform a concept design and economic evaluation for the same project. BACKGROUND This evaluation reflects that fact Seward already had operational experience with small hydro from Lowell Canyon from 1905 to 1938; and with the nearby Marathon Creek Hydro Project for several years in the mid 1980's. In 2019,the residents of Seward are very interested in slowing the rate of increase in grid electricity cost by supplementing their energy needs with cost effective small hydro. Lowell Creek remains one of the closest small hydro resources to the City of Seward; it has a steep drop in grade within the City limits from elevation 460 feet to sea level; and no fish species are present in the drainage. The waterfall outflow from the tunnel thru Bear Mountain is visible year-round to all who travel the road to Lowell Point. Acknowledgements. YCE would like to thank City Council, City Electric Department, and City Administration in Seward for taking this long awaited step towards developing a local hydro-electric project that taps the powerful and lucrative natural energy resource that is Lowell Creek. The support for this project by customers of the Seward electric system and greater community is also acknowledged. ANTICIPATED BENEFITS TO THE CITY FROM LOWELL CREEK HYDRO PROJECT • The City of Seward develops its own source of affordable, reliable and safe electrical power— to hedge off the increasing cost of CEA power generated primarily from fossil fuel sources — and to distribute the energy without transmission line loss. • Electrical costs in Seward will be reduced and stabilized over the 40 year project life with local hydro-electric power, especially if a majority of the project capital costs are funded by state and federal grants. • The City will have a reduced cost in standby / emergency power generation when local hydro- electricity is available. Every unit of hydro-electric energy produced can offset expensive fuel consumption by the City's back up diesel generators. • Hydro-electric power does not have the liability of pollution, and low impact run-of-river hydro- electric projects like the proposed one herein on Lowell Creek are typically very favorable to the public and state /federal agencies. Additionally, Lowell Creek has no fish species in the canyon drainage. • The City of Seward will be eligible for federal and/or state appropriations and/or grants for clean energy projects—once DNR & FERC permits are applied for, and in an active status. ■ "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 7 OF 20 COST OF POWER FOR CITY OF SEWARD -2019 The City of Seward currently has a Certificate of Convenience with the Regulatory Commission of Alaska (RCA)to operate its own electricity generation and distribution system. The primary source of energy for customers is long distance transmission delivered under a wholesale contract from Chugach Electric Association (CEA). CEA generates electricity primarily at their combined cycle natural gas facilities, with about 10%of total generation coming from large hydro-electric plants along the Railbelt. In recent years, the wholesale cost electricity from CEA has increased aggressively due to CEA's rate increases and fuel surcharges. The single long-distance transmission line that serves the Seward area remains vulnerable to interruption by seasonal avalanches. There also remains a section of 69KV transmission line supplying Seward that is undersized and imposes a line loss of up to 9% for every KWH purchased by the City from CEA. According to the City Electric Department, the City currently purchases CEA generation via long distance transmission at average wholesale price of approximately$.108/ KWH. It would be advantageous for the City to generate grid electricity with local hydro, if that local hydro was close in price to CEA's current wholesale price. Because the fuel for hydro-electricty is free and most annual cost components are fixed over the life of the project, the cost of local hydro-electricity will become increasingly attractive over the life of the project. In the event the City electric system becomes isolated from the CEA transmission due to avalanche or other event, the City must rely solely on its own Fort Raymond 15 MW diesel generation plant for standby generation. According to the City Electric Department, the cost of the City's diesel generation is typically in the range of $0.30/KWH. This high cost is due to fuel costs, labor costs, and emission requirements imposed by the federal government thru the Environmental Protection Agency(EPA). The City of Seward has a contract to directly purchase 1% of Bradley Lake hydro-electric generation at a wholesale price of approximately$.045 / KWH. This is a very low and attractive price for clean electricity on the Railbelt, however this allocation from Bradley Lake cannot be increased under the current contract. EXISTING HYDRO-ELECTRIC FACILITIES There are several components of the 1923 Seward Power& Light hydro-electric system that still remain in Lowell Canyon; none of these are still operational or useful. The reinforced concrete intake structure that was used from 1923 thru 1938 remains intact and in fair condition on bench above the stream channel in the upper canyon at approximate elevation of 450 feet. Stream flow was diverted into a shallow channel upstream of the structure; this flow then passed into a serpentine channel tank within the structure that ensured a water level above the three steel penstocks that exited the structure. Gravel,silt and debris were filtered and settled to a great extent within the tank of the structure, and the water flowed down the canyon in a single steel penstock that was suspended above grade level with wooden structural supports. In practice, the operators of that time period encountered challenges with flood stage gravel inundation of the intake structure; low surface flows in winter; and occasional ice formation on the interior walls of the penstock. The penstock terminated downstream in a concrete powerhouse that was located close to the intersection of Jefferson Street and 7th Avenue.This concrete powerhouse was heavily damaged by several large flood events that occurred in the period of 1923 thru 1938; these floods exceeded the capacity of the wooden flume channel that existed at that time down the Jefferson Street corridor. In addition to the concrete intake structure, heavily corroded sections of the old steel penstock can still be found at grade level down slope from the intake structure, and in scattered locations along the stream bed. The vertical support members have long rotted away; many of them were removed by the floods, landslides and snow slides that have occurred since this system was decommissioned in 1938. In credit to the designers of the 1923 intake structure, they identified a location that has remained free of landslides, snow slides, and flood waters for nearly 100 years. Tall trees and thick brush have established in the immediate area around the structure, this vegetation has stabilized the native soils and slopes in the same area. This location at elevation 460 feet remains today the most ideal for collecting the maximum stream flow from Lowell Creek at the highest elevation within the City limits of Seward. 0 "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 8 OF 20 HYDROLOGY The Lowell Creek canyon has a drainage area of approximately 4 square miles that is predominantly steep grade slopes that include significant snow fields into summer months at higher elevations. The steep sloping canyon walls have exposed layers of soft silty graywacke gravel that are easily eroded during flood events, transporting significant volumes of this same silty gravel down the canyon and thru the existing concrete tunnel thru Bear Mountain. The bottom of the stream channel consists of heavily weathered hard metamorphic bedrock shelves and large loose boulders. The variation of natural stream flow in Lowell Creek is significant between cold winter months when surface flow may freeze; and the heavy and extended rainfall and runoff events that typically occur each year in the months of September and October. With the advent of a warming climate and ever changing and unusual weather patterns in recent years, the streams flow in Lowell Creek is anticipated to be different in current years than was last measured by USGS 1965 thru 1968, and 1991 thru 1993, with a gage at the tunnel outlet. USGS re-installed a flow gage on the tunnel outlet in April 2019 and the flow data is available on-line. However, the hydrology that is most significant to the hydro-electric project proposed herein is the stream flow that occurs in the upper canyon at elevation 460 feet where a new intake would be located. There is no available stream flow data for this location from past or current years. A primary conclusion of this evaluation report is that it will be necessary for the City of Seward to establish a stream gaging station on Lowell Creek at elevation 460 feet; and monitor this flow for a continuous period of at least two years. From this new flow data,a more accurate duration curve can be developed to refine the proposed hydro-electric system design, and to secure the necessary water allocation permit from Alaska DNR. PROJECTED FLOWS BASED ON EXISTING DATA The most recent duration curve available that is based on stream gage flows in Lowell Creek can be found in the Feasibility Study completed in 1979 by CH2M-Hill. The duration curve presented in this study was based on flow measured at the tunnel outlet, and not at any higher elevations. No known gaging of stream flow has been done at the upper canyon intake before, during or since the time of the 1979 study. 1979 Study also suggested that approximately 60%of the surface flow observed at elevation 460 feet could be lost to the underground gravel aquifer before it ever reaches the tunnel entrance. This suggestion was based on a single set of flow estimations taken at the same time at elevation 460 feet and the tunnel outlet. Further measurements of surface and sub-surface flows are needed for a continuous period of several years in order to confirm the presence of underground flow in the porous gravel of the creek bed. Such measurements would also confirm whether some of this underground flow can be intercepted year-round with an infiltration gallery to supplement a surface screen intake for hydro-electric power production. For this evaluation, the 1979 duration curve was extrapolated to include additional underground flow based on estimates provided in the same 1979 study. This extrapolated duration curve suggests that it may be possible to collect at elevation 460 feet an average of 40 CFS flow for up to eight months of the year; an average of 10 CFS flow for up to two winter months of the year; and an average of 50 CFS flow for up to 2 months in late summer and early fall. The maximum flow thru the intake system, 7200 foot long penstock, and turbine house would be 60 CFS. 0 "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 9 OF 20 PROJECTED FLOWS BASED ON EXISTING DATA(CONT'D) A duration curve was developed and included in the 1979 Lowell Creek Feasibility Study prepared by CH2MHill. This curve was for stream flow measured at the Bear Mountain tunnel outlet. The 1979 Study also suggested that 60% additional flow may be available in the upper canyon at elevation 460 feet due to the fact that a significant portion of the stream flow seeps down through porous alluvial gravel before it reaches the tunnel entrance. For the purposes of this evaluation, a more conservative estimate of 50% additional flow at elevation 460 ft was used, and the duration curve was extrapolated accordingly. The best way to confirm and update this duration curve is to gather and compile several years of current flow data at elevation 460 feet. This flow data is also needed to secure the necessary DNR water rights permit to divert stream flow at this location. 01 ��... i � �w �� - ��........ww Mosswod ow 68 40 3 ............... ....... .o. ILE n"IRAPOLA r-ED FOR IN TA K IIE IO,CA I EID A L q " ELEV 4L601 If°T , INCLUDES ICJCt""ION L,E0"'44 FLOW .......... .aw,. . ra i 01 20 40 GO 80 100 PERCENT OFTIMEi ■ "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 10 OF 20 RUN OF RIVER COANDA STYLE INTAKE WITH BURIED INFILTRATION GALLERY The method of collecting stream flow from elevation 460 feet in the upper canyon proposed in this concept design consists of two independent systems. The first is to construct a stream diversion that will direct surface flow over a series of parallel coanda style runoff river intake screens. These screens allow a portion of the surface flow to pass thru the screen area and fall into a collection box that keeps water level above the penstock entrance. Under low to moderate flows, these screens are self-cleaning because that portion of the flow that passes over the screen surface will carry with it gravel and debris that may otherwise come to rest on the screen. However, during very low flows and cold winter conditions, these surface screens are prone to frazil ice formation which often blocks the openings thru which water can pass. During these low flow winter months, it appears more advantageous to collect some portion of the flow needed for a hydro-electric facility from warmer water found flowing below grade. The second method of collecting stream flow that is considered in this concept design is to install a French drain style infiltration gallery that is located upstream of the surface screens, and adjacent to the stream bed. It appears that warmer water that is migrating underground thru the gravel stream bed can be intercepted in a flow range of 10 to 20 CFS during winter months. Collection of this flow could allow the hydro plant to remain operational at part load flows when the surface water and coanda style screens are prone to freezing. A recent aerial photo of the project site, showing proposed intake location, is shown below: Lowell Creek Intake Concept Ganvnn Hy(k�-zr QO� 9 -Proposed Intake Loeatoon r-. ■ "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 11 OF 20 RUN OF RIVER COANDA STYLE INTAKE WITH BURIED INFILTRATION GALLERY(CONT'D) /�. �ilGo i j VnfiVtUatian GalBey ✓ / Sluice Gates / ��✓ 1��� Intake Screen, � � � ✓�� ��� � � Penstock of i f Lowell Creek Intake Concept C,any,,n Hydra-'c"latir M c ,xs xw czn A conceptual illustration of the proposed two-part intake system at elevation 460 feet is shown above. The infiltration gallery will collect underground flow at an elevation above that of the surface screens. PENSTOCK MATERIAL SELECTION The proposed hydro-electric system concept design includes a 42-inch diameter penstock of 7,200 foot length. This diameter is proposed to keep friction and hydraulic losses less than 15%of the total available elevation head at the maximum flow of 60 CFS thru the penstock . The following pipe material is considered for the project at this time: High Density Polyethylene (HDPE): the flexibility of this pipe material, along with the option of field fused joints, make this an ideal pipe material for the upper portion of the penstock alignment. To reduce construction time, long sections of the penstock can be pre-assembled in the field, then dragged into the excavation trench. This pipe material is very smooth wall and ensures low friction loss over long distances. Additionally, this pipe material is highly resistant to corrosion and abrasion. However, the pressure class of the pipe is also limited due to the lower tensile strength of HDPE, and accordingly this material can only be used in higher elevation section of the penstock where static pressure and surge pressures will not exceed the safety factor of the pipe material. Welded Steel: the high tensile strength of this material, and competitive cost, make this material an ideal choice for the lower elevation portion of the penstock. The pressure class of the welded steel pipe will increase as the static head increases down the penstock, up to the connection with the pre-fabricated turbine assembly in the turbine house. This pipe requires straight alignment due to very limited flexibility at joints; and may also require a cathodic protection system to prevent long term corrosion of the pipe material. 0 "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 12 OF 20 HYDRO-ELECTRIC ENERGY PRODUCTION • Initial turbine sizing would be one vertical shaft five jet pelton wheel, rated for 60 CFS flow = 1.8 MW capacity. • During low flow periods in winter, the turbine can be run as low as 10% of rated capacity and still produce stable grid power (6 CFS = 0.18 MW= 180 KW). • A below grade infiltration gallery upstream of the surface screen intake may allow continuous minimum winter flows of 10 CFS, enough to keep one turbine running from December through March and keep intake box and penstock from freezing. Hydro Power= Elevation Drop x Flow Thru Turbine specifically: Theoretical Power (kW) = HEAD (feet) x FLOW (cfs) 11.81 Actual power must account for: Energy losses thru screen intake & collection channel Energy losses thru penstock, bends, valves, nozzles Energy losses in turbine, shaft, drives, generator, wiring ESTIMATED HYDRO-ELECTRIC ENERGY BASED ON PROJECTED STREAM FLOWS The quantity of hydro-electric energy(KWH)that could be produced annually from the proposed concept design can be estimated as follows: Total head available above sea level =460 ft elevation minus screen intake loss (5 ft), minus friction loss in (35 ft) minus tailrace drop to sea level (15 ft) =@405 ft net head Hydro mechanical/electrical system efficiency(turbine to grid) = 92% (turbine)x 96% (alternator)x 96% (grid tie) = @84.7% - For 8 months avg flow @ 40cfs = 6,692,300 KWH - For 2 winter months, avg flow @10cfs = 418,300 KWH - For remaining 2 months, avg flow @ 50cfs = 2,091,400 KWH --------------------- ESTIMATED ANNUAL HYDRO-ELECTRIC ENERGY = 9,202,000 KWH ■ "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 13 OF 20 HYDRO-ELECTRIC TURBINE EQUIPMENT SELECTION The net head available at the turbine house for the proposed project is approximately 405 feet. With a design flow of 60 CFS, the ideal turbine selection would be a single five jet vertical pelton wheel turbine system. These turbine systems are currently available for Alaska projects through both Canyon Hydro of Deming, Washington; and Gilkes Hydro (UK)who have offices in the Seattle area. The pelton wheel is a high efficiency impulse turbine that converts kinetic energy from one or more high pressure water jets into rotation of the turbine wheel. The water jet is split by a knife edge divider between two stainless steel buckets that can absorb over 90%of the kinetic energy from the water jet. Pelton wheel turbines with multiple jets are capable of producing stable grid electricity with flow as low as 10% of their rated capacity. A five jet vertical pelton system would allow the Lowell Creek Hydro turbine to stay operational in winter months with flows from the upper canyon as low as 6 CFS. a , %`' y,'4UhdNihNti FNr �y High efficiency Pelton wheel turbine with stainless steel split bucket design u P „ 1 n i Y / Jay Five jet vertical pelton wheel turbine system installed (photo courtesy of Canyon Hydro) ■ "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 14 OF 20 TURBINE HOUSE CONCEPT DESIGN The east end of Jefferson Street continues an existing 100 foot wide right-of-way into the RV and tent camping area that is managed by the City's Parks and Recreation Department. This corridor is clear of utilities or permanent structures with the exception of an existing 24" drain culvert that parallels Jefferson Street, and the remains of the historic wooden/steel flume from the late 1930's still located on the beach. The proposed 42" penstock could be routed straight down Jefferson Street to a new turbine house located between the two camping areas. This location affords the maximum drop in elevation from the upper canyon to sea level; the floor level of the proposed turbine house would be approximately +27 ft. The proximity to campers and recreational visitors would require that the turbine house and tailrace structures be heavily insulated to prevent turbine noise from migrating out from these structures. rz i I I �I I ` N ul Ea. W The east end of the Jefferson Street R.O.W. corridor extends in the City's Waterfront Park I � Iw89 59'22"iw 368.10' # �`n I (232 k1) 232.00 86.f0 0.00 , 2p JEEEERSON S T, F S89 59'22'E 408.06 j 4©' 140' 232 R1 232.00 59.92' 2.00' S89 59 22" 353, 92' AQ ■ "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 15 OF 20 TURBINE HOUSE CONCEPT DESIGN (CONT'D) The Jefferson Street R.O.W. corridor is 100 feet wide through the Waterfront Park area to the edge of Resurrection Bay. It appears feasible to locate the turbine house for the hydro-electric project within this R.O.W. without significant modification of the City's existing RV and tent camping activities. Flow leaving the turbine house would be routed straight down to the ocean in a below grade insulated tailrace with submerged outlet below low tide level. This design approach would afford the greatest sound mitigation and provide safe discharge of turbine house flow in an area heavily used by visitors and residents. gm IF .. ..,...,, i o err s ,,_,: 100 FT Rout EXTENDS©INTO? CAMPGROUND P %///% / EXISTING 24"CMP STORM DRAIN LET gg' A turbine house located in the Waterfront Park allows for a straight penstock alignment down Jefferson St; maximum elevation drop for energy production; and safe and easy access to the turbine equipment. 32 FT X 40 FT(HYDRO TURBINE HOUSE CONCEPT FLOOR PLAN HYDRO CONTROL (PAD PANELS MOUNTED 41$OWI TRANS FIVE JET ,''c _ ^�-C FORMER L..... VERTICAL ' .�`° "1, ........ PIELTON w Ar GENERATOR SwITCHGEAR 30"BALL VALVE "Celebrate the power of nature"T. ...with YourCleanEnergy LLC LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 16 OF 20 TURBINE HOUSE CONCEPT DESIGN (CONT'D) The proposed turbine house concept design is one that presents an attractive, low profile, and well insulated structure that can integrate into the existing campground area with minimal visual and operational impact. The pad-mounted step up transformer would be enclosed in an attached shed structure on the west side of the turbine house. The primary access door to the turbine house would be on the east (ocean) side, along with site parking for utility staff. The entire turbine house and subsurface concrete tailrace would be heavily insulated to mitigate turbine noise. Below are renderings that show the proposed turbine house design concept when placed into site photos of the City right-of-way of Jefferson Street: w �w .�„+ ,, r o Dili,uTn�imvinr,pir,J9nr2um�rlu��wiev9p"ry�i t r, a!iri r r �,Y,,r�m�lv9rviu JJf ihifi b * ,a,,: ,,,e,e;, tu, � ,r .. `s✓ li t+M YY IP»YlpYdlYUVilllfl MlYgIN�,.,Y1N1� I.1)fl 1 ) J � ..,, ..'; «, ,, way»v rtia nmi�aiwuww�H r i�✓r a Mr im g wimiue�mr�mur!�h�rr r�� 1 , x v � f i J �J"rse rid l��ri �a �!"i�,,„,'"� ,J„iIy,,/,,,r- ,,,,,, .;..,n/ -�` l ,('rrW mrAL,�wiiiir,c��1�I�i�r�!.<Ir/11� J/l�rctili��i��r�A,,/�il�iFi illl7/N/%iart�r�/G�sr✓, ""' ,,.„.�r.r�✓�rfriN�1.��,rio//r�✓/l�%il(�lcJ✓�✓ u� ��H. ��i7111/Jl,,. ,..../1.,y,� �.�, /,�„ ,��. i/✓11 r /r, :;: s,c,.,a„ a�i ,,,;, Fr i i r;lu�l� �lr��`/ink✓/�r���as��'d;��d'/���i�/��1����i�1��61/�UURr��i�G!�Jl�/,�n/ririnwii�io9d'N�.�'I��;o,/ VI �i"4 Pr" 4.�p�" � ,,;..y�� Looking east across Ballaine Avenue. (Site photo and rendering by YourCleanEnergy LLC). e� Il s ti7 f ` m y 'Wu is y,u� lid, 5aa4r � r� i ��r�r�rr,( ✓ iu 14 Looking west from Waterfront bike path. (Site photo and rendering by YourCleanEnergy LLC). "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 17 OF 20 EVALUATING HYDRO PROJECT COSTS VS BENEFITS The proposed hydro-electric project concept can be evaluated in two fundamental ways: A. Life Cycle Cost (how many years to fully pay back initial capital investment?) B. Annual Energy Cost ($ per kwh over the anticipated project life) Typically, once a hydro-electric power resource is developed,the projects are run as long as the community can maintain them, often more than 50 years. What will be most important to the City of Seward is to keep the annual energy cost of hydro-electric energy as low as possible to stabilize overall grid power costs. The Lowell Creek Hydro Project, if built, is anticipated to have a 40 year project life. Therefore, in this evaluation, the method of Annual Energy Cost is used to evaluate the proposed concept design. OPINION OF PROBABLE CAPITAL COSTS— PROPOSED HYDRO-ELECTRIC PROJECT-2019 An itemized breakdown of anticipated project construction components is given below: Construction Phase Component Cost Opinion DNR land lease and land easements $ 40,000 Access road to new intake site at elevation 460 feet $ 616,000 Stream diversion, intake screens and collection channel $ 500,000 Groundwater Infiltration gallery piping and collection $ 300,000 Penstock (7,200ft x 42 inch dia), including selected buried utility relocations $ 5,120,000 Turbine House/power plant building $ 1,800,000 Turbine and generator equipment $ 1,500,000 Electrical control equipment $ 300,000 Miscellaneous power plant equipment $ 84,000 Pad Mounted 4160 V/ 12.5 KV Transformer $ 40,000 Buried conductors and devices $ 60,000 Overhead conductors and devices $ 60,000 Communications equipment $ 80,000 Insulated concrete culvert tailrace and submerged ocean outfall $ 500,000 CONSTRUCTION SUB-TOTAL $11,000,000 ■ "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 18 OF 20 OPINION OF PROBABLE PROJECT COST—PROPOSED HYDRO-ELECTRIC PROJECT-2019 The following are components included to estimate the total project cost: CONSTRUCTION COST SUB-TOTAL $11,000,000 CONTINGENCY AND UNLISTED ITEMS (15%) $ 1,650,000 --------------- TOTAL DIRECT COST $12,650,000 INDIRECT COSTS: TEMP FACILITIES, BOND, INSURANCE, OHEAD (17%) $ 2,150,500 - ------------- TOTAL CONSTRUCTION COSTS $14,800,500 ENGINEERING, LEGAL, ADMINISTRATION (15%) $ 2,220,100 NET INTEREST DURING CONSTRUCTION (6%) $ 888,000 --------------- TOTAL HYDRO-ELECTRIC PROJECT COST $17,908,600 The project will become financially attractive to the City Of Seward with the assistance of grant funds to offset the initial capital cost. The project has a high public benefit and profile and represents a positive step forward for the City to produce a portion of its power from renewable energy. Therefore, both state and federal grant agencies may show interest in supporting the project when political will for the project is clearly expressed by the community. These grant funds will reduce the amount of general obligation bond that the City will have to issue to supplement the available state and federal grant funds. This evaluation includes an opinion of probable grant funding in order to arrive at an estimated bond issue amount,which in turn will determine the estimated cost of producing hydro-electric power from the project. TOTAL HYDRO-ELECTRIC PROJECT COST $17,908,600 LESS STATE (@$5 MILLION)AND FEDERAL (@$6 MILLION) GRANT FUNDS ($11,000,000) ------------------- TOTAL INVESTMENT BY CITY OF SEWARD $ 6,908,600 CITY OF SEWARD BOND ISSUE (110% OF TOTAL INVESTMENT) $ 7,600,000 ■ "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 19 OF 20 ESTIMATION OF PROBABLE ANNUAL COSTS— HYDRO-ELECTRIC FACILITY-2019 CITY OF SEWARD BOND ISSUE (110% OF TOTAL INVESTMENT) $ 7,600,000 INTEREST &AMORTIZATION (40 YEARS @ 4% INTEREST RATE) $ 383,770 INTERIM REPLACEMENTS (1.0% OF TOTAL CONSTRUCTION COSTS) $ 148,000 INSURANCE (0.4% OF TOTAL CONSTRUCTION COSTS) $ 59,200 OPERATION AND MAINTENANCE $ 320,000 ADMINISTRATIVE AND GENERAL (50% OF O&M COSTS) $ 160,000 LESS INTEREST EARNED ON RESERVE FUNDS (@ 6%) ($ 23,000) --------------- TOTAL ANNUAL COSTS $ 1,048,000 TOTAL KWH PRODUCED PER YEAR (FROM PREVIOUS SECTION): 9,202,000 KWH ANNUAL ENERGY COSTS =TOTAL ANNUAL COSTS/KWH PER YEAR: $ 0.1139/KWH OPERATIONS The proposed hydro-electric system concept design is a run-of-river type system that includes no impoundments for high elevation storage. It would provide no storage for daily peaking operation. The hydro-electric turbine generator cannot operate when penstock flow is lower than 10% of the rated flow capacity of 60 CFS. It is anticipated that the hydro-electric turbine may need to be taken off-line during flood events when the stream flow exceeds 75 CFS as the bed load of silt and gravel in Lowell Creek during these short-term events can be destructive to intake surface screens. It is also anticipated that there may short periods in mid to late winter of some years when the total stream flow may not be greater than the minimum 6 CFS required to keep the hydro-electric turbine operating. This is again why it will be necessary for the City to collect flow data on the stream for several years at the proposed intake location at elevation 460 feet. With a warming climate and changing winter temperatures, rainfall, and snow melt patterns, having current flow data will give more accurate indication of the expected frequency of both flood events, and periods of low flow in winters. Periodic inspection and cleaning of debris from the intake diversion channel,surface screens, and collection box will be part of the operation of the proposed hydro-electric system. The gravel access road in the upper canyon will pass thru several slide areas that will likely require some clearing and re-grading with heavy equipment each year. In the turbine house, the high velocityjet nozzles and pelton wheel will experience accelerated abrasion from fine glacial silt particles suspended in the flow that cannot be screened or settled out. Replacement of the turbine wheel every five to eight years is anticipated, the worn turbine wheel can be factory repaired by weld re-building of the stainless steel buckets. The synchronous generator will require regular inspection and lubrication, similar to most other large three phase grid tied generator units. 0 "Celebrate the power of nature"T. ...with YourCleanEnergy«C LOWELL CREEK HYDRO PROJECT EVALUATION CITY OF SEWARD 6/21/19 PAGE 20 OF 20 WATER RIGHTS The proposed concept design for a hydro-electric system includes a stream diversion and intake at elevation 460 feet in Lowell Canyon. This intake location lies on a parcel of land owned by Alaska DNR that lies within the City limits. The primary agency for adjudicating water rights for this intake location is the Water Resources Section of the Alaska DNR. Conversations with YCE and DNR regarding water rights for the City for this hydro-electric project began in February of 2019. On March 14, 2019,with assistance from YCE, the City submitted an "Application for Water Right"to DNR. This application requested an allocation for diverting up to 75 CFS into a penstock at elevation 460 feet, and release of the same flow into Resurrection Bay at the east end of the Jefferson Street corridor. On March 27, 2019, DNR Water Resources Division advised that the City's "Application for Water Right" had been received, and advised that the following additional information is required from the City to fully complete the application for water right for the proposed intake at elevation 460 feet: "Provide a hydrologic study(of Lowell Creek at elevation 460 feet) as the requested water quantity is more than 100,000 gallons per day from a stream." "Provide documentation in the form of a Lease, Easement, Deed, or notarized and recorded Water Use Agreement, which authorizes access to requested water resource as the requested water resources is not located within the boundaries of the property where the water is to be used." "Provide a copy of an executed deed, lease agreement, or other possessory interest document showing ownership of, or authorization to use, the property where the water will be used." A copy of the March 27 2019 letter from DNR Water Resources Section confirming the City's "Application for Water Right" is a included at the end of this evaluation report. Conversations with DNR since the time of the "Application for Water Right" was made have expanded understanding of the scope of hydrologic study that DNR will accept for this stream diversion at elevation 460 feet. A gaging station is to be established to collect stream flow for a minimum period of two years at the proposed 460 feet elevation intake. An additional suggestion has been made by DNR to install and monitor several groundwater wells in the location where an infiltration gallery could be located, also for a period of two years. This data can be used to develop a new duration curve that reflects the current climate conditions for the Lowell Creek drainage area. Stream flow data collected from elevation 460 feet can be compared to that collected by USGS at the Bear Mountain tunnel outlet to determine how much stream flow is typically lost to the alluvial gravel stream bed before entering the tunnel. In conclusion, it will be in the best interest of the City to engage the USGS, or other qualified professional and experienced hydrologist to begin the necessary stream flow and underground water table measurements at elevation 460 feet in the upper canyon of Lowell Creek. A two year hydrologic study is anticipated to cost in the range of$60,000 to $100,000 depending on the equipment that is used, and the frequency of flow and water level measurements. 0 "Celebrate the power of nature"T. ...with YourCleanEnergy«C