HomeMy WebLinkAboutAkutan Town Creek Hydro Closeout Report - June 2017 - REF Grant 7030003
Akutan Hydro
Grant Closeout Report, June 7, 2017
Project Overview
Project Title Town Creek Hydro
FERC status Unknown, not licensed
Grantee/Owner/Developer City of Akutan
Project Region Akutan, Aleutian West
Local Electric Utility City of Akutan
Project Description
The existing Akutan Hydro Project was commissioned in 1993 and is located on a steep hillside
that abuts the north side of the town of Akutan. The Project is a run of the river (ROR) alternative
involving four diversion structures in the upper reaches of the Town Creek drainage. The intake
works for the final conveyance are at about elevation 820 feet. Up to 3.5 cfs of water is diverted
from the creek into a 10 inch penstock to generate up to 105 kilowatts of power via a pelton
turbine at the powerhouse elevation of about 20 feet (estimated, turbine nameplate 150 kW at
685’ net head). The estimated potential annual generation for the project is about 300 MWh
based on past performance but it is likely able to produce significantly more power and energy.
Grant Award(s) and Budgets
REF Grant Application Summary:
Round App Number Amount Requested Amount Recommended Award Code
2 248 $237,772 $237,772 2195472
2 249 $1,795,450 $162,000 2195473
3 469 $1,391,000 $1,391,000 7030003
REF Grant and AEA Managed Award Summary:
AEA Award Code Grant Funds Grantee Funds Total Spent
NA (Project 407002) $204,382.77 0 $204,382.77
2195472 $206,295.92 0 $206,295.92
2195473 $162,000.00 $162,000.00
7030003 $1,391,000.00 $135,633.35
A $1,526,633.35
Total $1,963,678.69 $135,633.35 $2,099,312.04
A: Required match equaled $100,000.00
Alaska Energy Authority
Akutan Town Creek and Loud Creek Hydroelectric Project
Grant Closeout Report
6/7/2017 Page 2 of 11
Execution of work
The Town Creek Hydro briefly produced power in 2003 and again in 2007. Federal grants
managed by AEA in 2007 were used to upgrade the controls at the existing Town Creek Hydro.
Despite this effort the Project was offline again from 2008 through 2012 and again in 2015.
Since 2003 the Project has generated reliably 4 years averaging about 120,000 kWh each year.
The estimated potential annual energy from the project is calculated as the sum of all the top
energy producing months in the PCE record.
In 2008 the City of Akutan applied to the Renewable Energy Fund (REF 2195473) for 3 projects:
the rehabilitation of the Town Creek Hydro, a feasibility study of the Loud Creek hydro
resource, and an application for geothermal investigation (one of 3 geothermal awards to
Akutan totaling approximately $5.5 million). The justification for the geothermal project is to
supply power for Trident’s seafood processing operations in Akutan. The Loud Creek hydro
justification is to allow the City to meet current and future demand (from City growth) entirely
from hydro resources.
The funding awarded for the Round 2 Application 249 (REF 2195473) for the repair of the project
was limited to $162k to perform the inspection and design of repairs. Work began in October of
2009 with meetings with contractors followed by a site visit and the report “Town Creek
Hydroelectric Project Field Report and Recommendations for Improvement, March 2010”. After
review and comments the scope of work was refined and work began with LIDAR and other
data collection in the latter half of 2010 although weather forced the LIDAR collection to be
delayed. In 2011 the dam safety report and condition assessment report were revised and
construction drawings were submitted in early 2012.
The feasibility work for Loud Creek was performed generally simultaneously as the design of
the repairs for Town Creek. In October 2009 a site visit was made with plans to install a stream
gauge on Loud Creek although weather prevented the installation until February 2010 when
local Akutan residents installed the gauge on Loud Creek. In March of 2010 the draft feasibility
report “Loud Creek Hydro Project Draft Conceptual Design and Feasibility Report, March 31
2010” was completed. A stream gauge site visit by the contractor occurred in July 2010 and
September 2011 and revisions to the feasibility report continued through 2010 and 2011 with
the completed report issued July 29, 2011. Stream gauging work continued with another site
visit in March and a draft monitoring report, a site visit in August 2012, and the final site visit in
June 2013. A final stream gauging report “Loud Creek Gage Assessment, Final Loud Creek
Streamflow Monitoring and Assessment Report, October 3 2013” was completed.
Geothermal work is ongoing as of the writing of this report. Geothermal work is generally
separate from the scope of the hydro work in that it is too large of a project to serve the City of
Alaska Energy Authority
Akutan Town Creek and Loud Creek Hydroelectric Project
Grant Closeout Report
6/7/2017 Page 3 of 11
Akutan’s energy demands and is more suitable for supplying electric energy to Trident Seafoods
for their processing operations.
Discussion
Stream gauging, which was completed last, is discussed first since it is of the most importance
to the analysis of the energy potential from both the Town Creek and Loud Creek resources.
Seven stage discharge measurements were made at the stream gauge location on Loud Creek
ranging from a low of 0 cfs to 15.4 cfs. The transducer equipment apparently utilized a bubbler
system. While generally quite reliable the contractor experienced problems with clogging that
impacted the readings. The report states that only the data from February 2010 to mid January
2011 is reliable. However, AEA’s review finds this data to be suspect as well. AEA recommends
that the USGS Russel Creek gauge data should form basis for hydrological analysis at this time
as was done in the feasibility report.
Three developments of interest are examined in this closeout report by AEA. They include Town
Creek, Loud Creek, and Harbor Creek (name made up, watershed west of the boat harbor). All
the analysis was done using the Russell Creek hydrology data scaled to the respective
watersheds of each project. The configurations are shown in the table below. It is evident that
the Town Creek project is the best resource based on this approximate analysis.
Project Loud Creek Harbor Creek Town Creek Upgrade Town Creek Exist Units
Watershed Area 0.66 0.58 0.52 0.52 sq mi
Intake Elevation 550 620 800 800 ft
Turbine Elevation 20 40 20 20 ft
Peak Flow 9.5 8.4 7.6 3.5 cfs
Power 350 330 420 150 kW
Annual Energy 1,580,000 1,520,000 1,890,000 1,140,000 kWh
When comparing the project configurations with the demand of Akutan it is also evident that
the existing Town Creek turbine with a nameplate capacity of 150 kW should be adequate to
meet most of their power needs given the hydrology assumptions in this report.
Town Creek, Existing Hydro
Month
Estimated Average
Monthly Stream
Flow, cfs
Estimated Average
Power, kW
Average Akutan
Demand, kW
Average Akutan
Peak Demand, kW
1 5.1 93 64 83
2 4.4 80 61 86
3 4.1 75 72 90
4 4.4 80 68 94
5 6.8 124 64 83
Alaska Energy Authority
Akutan Town Creek and Loud Creek Hydroelectric Project
Grant Closeout Report
6/7/2017 Page 4 of 11
6 9.7 178 59 75
7 9.7 177 61 79
8 8.6 159 62 77
9 9.4 173 61 82
10 8.2 151 62 86
11 8.0 146 61 87
12 7.3 134 66 86
Average 7.1 131 63 84
Taking a closer look at the existing Town Creek hydro, the cumulative annual power generation
based on the scaled Russell Creek discharge record is shown below.
Based on the above, a rough estimate is that Akutan should be able to generate about 90% of
its energy from the exiting Town Creek hydro with the diesels running about 15% of the time
(derived from the cumulative duration chart). The performance of the existing Town Creek has
not come near this. Factors such as hydrology differing than that assumed herein, poor
programming, or operation and maintenance issues, or a combination thereof could be the
cause.
The first priority for Akutan is to focus on understanding the Town Creek resource potential and
why the project is not operating anywhere near its estimated capability. The condition
assessment report for Town Creek did not provide a specific reason for the poor operation
although it is likely due to a long term failed head level sensor and excessive restrictions in flow
0
20
40
60
80
100
120
140
160
180
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%Town Creek Power Capability, kWPercent Time of Year
Cumulative Duration, Town Creek Exist
Alaska Energy Authority
Akutan Town Creek and Loud Creek Hydroelectric Project
Grant Closeout Report
6/7/2017 Page 5 of 11
caused by clogging from organics and sediment. The lack of operation probably exacerbates the
clogging issue particularly on startup.
The following tables shows the history of hydroelectric generation from Town Creek hydro from
PCE data.
Year Diesel kWh Generated Hydro kWh Generated Total kWh Generated
2003 537,520 12,286 549,806
2004 574,650 1,664 576,314
2005 528,244 0 528,244
2006 535,352 0 535,352
2007 440,881 103,762 544,643
2008 609,862 825 610,687
2009 667,067 0 667,067
2010 12,924
2011 504,690 0 504,690
2012 501,375 42,111 543,486
2013 373,001 189,900 562,901
2014 530,167 86,922 617,089
2015 613,592 2,142 615,734
2016 463,935 112,431 576,366
Summary of Work, Budget, and Schedule
Major Deliverables
Town Creek Hydroelectric Project, Dam Safety Report, December 16 2010, McMillen
Loud Creek Hydro Project Conceptual Design and Feasibility Report, July 29 2011, EES
Consulting, McMillen, Dryden & Larue/EPS
Town Creek Hydroelectric Project, Condition Assessment Report: Revised, January 4, 2012,
McMillen, EES Consulting
Town Creek Hydroelectric Project Improvements and Repairs, Technical Specifications, July 13
2012, McMillen
Town Creek Hydro, Energy Production Analysis, July 17 2012, McMillen
Town Creek Hydroelectric Project Improvements and Repairs, Construction Drawings, November
2012, McMillen
Town Creek Hydroelectric Project, Construction Completion Report, January 2013, McMillen
Town Creek Hydroelectric Project, Emergency Action Plan, January 2013, McMillen
Town Creek Hydroelectric Project, Operations and Maintenance Manual, January 2013,
McMillen
Loud Creek Gage Assessment, Final Loud Creek Streamflow Monitoring and Assessment Report,
October 3 2013, McMillen
Akutan SCADA System User Manual, December 18 2014, Electric Power Systems
Alaska Energy Authority
Akutan Town Creek and Loud Creek Hydroelectric Project
Grant Closeout Report
6/7/2017 Page 6 of 11
Project Costs by Phase/Task (REF funds only) Amount Source
Loud Creek Feasibility $206,295.92 0
Town Creek Design $162,000.00 0
Town Creek Construction $1,391,000.00 $135,633.35
Total $1,759,295.92 $135,633.35
Performance Evaluation
Since the recent completion of controls work (in 2016) the project has seen significant
improvement in operation. However, the performance is still not as high as expected.
Month
Diesel kWh
Generated
Hydro kWh
Generated
9/1/2016 30,858 15,167
10/1/2016 29,878 17,399
11/1/2016 28,893 21,689
12/1/2016 30,572 24,409
1/1/2017 21,135 14,562
2/1/2017 39,191 5,425
3/1/2017 48,565 4,541
4/1/2017 36,258 8,830
Lessons Learned
Difficulty in accessing remote Aleutian sites is common.
Buying the best and redundant stream gauging equipment pays off by improving the odds of
obtaining useable data. The problems with equipment on this project resulted in only a useable
stage discharge charge curve for the chosen gauging site.
Controls and local operation and maintenance capabilities have a very significant impact on
energy production.
Future Work and Recommendations
Accurately monitor the spill and water usage at Town Creek to assess the hydrology and potential
to generate more energy. If possible, continue the Loud Creek discharge monitoring as well.
The penstock exhibits higher frictional losses than expected according to the Field Report (March
2010). Organic growth on the inside of the penstock walls could be a possible cause. Growth can
accumulate on plastic pipe where the water is stagnant and contains sufficient nutrients. The
problems with organic growth on the intake screens is an indicator that such conditions exist.
This type of problem was discovered on a water supply line in Petersburg, Alaska. It is
recommended that the possibility of organic growth on the penstock line be investigated and
remedied so that the project will produce more energy by reducing frictional losses.
Alaska Energy Authority
Akutan Town Creek and Loud Creek Hydroelectric Project
Grant Closeout Report
6/7/2017 Page 7 of 11
Intake screens can be made of copper or copper coated which will prevent clogging from algae
growth.
The inverted overflow pipes on the main impoundment are not likely to flush accumulated
sediment. A sediment flushing gate or pipe should be located or installed through the dam and
operate it occasionally during high flow/spill events.
Project Location Map
Alaska Energy Authority
Akutan Town Creek and Loud Creek Hydroelectric Project
Grant Closeout Report
6/7/2017 Page 8 of 11
Photographs
Town Creek Hydro and Community of Akutan
Town Creek Hydro east diversion and main impoundment in background
Alaska Energy Authority
Akutan Town Creek and Loud Creek Hydroelectric Project
Grant Closeout Report
6/7/2017 Page 9 of 11
Town Creek weir below main impoundment
Alaska Energy Authority
Akutan Town Creek and Loud Creek Hydroelectric Project
Grant Closeout Report
6/7/2017 Page 10 of 11
Town Creek turbine
Alaska Energy Authority
Akutan Town Creek and Loud Creek Hydroelectric Project
Grant Closeout Report
6/7/2017 Page 11 of 11
Loud Creek