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HomeMy WebLinkAbout20130625 trip report If you disagree with any information contained herein, please advise immediately , Rev. A Page 1 © Hatch 2013 All rights reserved, including all rights relating to the use of this document or its contents. Trip Report 6/25/2013 Port Alsworth Imp. Corp. Tanalian Falls Hydro Distribution Those present + Beth Hill Seth Kroenke Field Reconnaissance Date: 5/22/2013 Location: Alaska Port Alsworth Present: Daniel Hertrich Purpose: Investigate hydro potential at falls 1. Introduction Having discussed at the 2013 Alaska Renewable Energy conference the arrangements for a site visit by AEA it was agreed that Daniel Hertrich of Hatch would perform a site visit to the community of Port Alsworth to perform a reconnaissance of the Tanalian Falls for hydroelectric development potential. The community paid the airfare for the travel on Lake Clark Air. Mr. Hertrich departed Anchorage around 9:30 am and immediately proceeded with the a hike to the falls upon arrival in Port Alsworth at around 10 am. The distance to the falls is approximately 1.75 miles along a foot trail through the park land. Lake levels and flows appeared to be at very low levels which was later confirmed as unusual according to residents and is attributed to the late spring impacting many Alaska area drainages. Weather was partly sunny and about 50 degrees F. 2. Findings A height measurement of Tanalian Falls was made using a handheld gps and inclinometer. A target boulder at water level downstream of the falls was sighted from the water surface level , Rev. A Page 2 © Hatch 2013 All rights reserved, including all rights relating to the use of this document or its contents. just above the crest of the falls. An incline measurement of 22.5 percent was recorded along with the horizontal distance of 135 feet between gps waypoints resulting in a falls height of 30 feet. Flow over the falls was visually estimated to be 50 - 100 cfs. Local residents report current electrical demand averages approximately 110 kW which is supplied by diesel generation. The community relies entirely on air freight for fuel shipments. 3. Analysis Assuming a net generation efficiency of 60% the potential output of a hydro at a flow of 50 cfs would be approximately 75 kW. A report by the Alaska Power Authority indicates the basin area is 200 square miles and the average annual runoff is 461,000 acre feet (637 cfs). As a comparison, scaling the USGS reported average annual flow for 2010-2011 in the Chulitna River (basin area 1120 square miles) equals 282 cfs. Conservatively, the average monthly flows for the Chulitna River are used to determine monthly power, energy, and displaced fuel assuming a peak project capacity of 150 kW and a diesel efficiency of 13 kWh/gal. Estimated Monthly Energy and Displaced Fuel Month Avg Flow (cfs)Power (kW)Energy (kWh)Fuel  Equivalent  Jan 67 100 74,334 5,718  Feb 56 85 56,880 4,375  Mar 54 81 59,985 4,614  Apr 126 150 108,000 8,308  May 498 150 111,600 8,585  Jun 380 150 108,000 8,308  Jul 421 150 111,600 8,585  Aug 714 150 111,600 8,585  Sep 479 150 108,000 8,308  Oct 316 150 111,600 8,585  Nov 158 150 108,000 8,308  Dec 90 134 100,041 7,695  Average 280 133 Total    1,169,640 89,972  , Rev. A Page 3 © Hatch 2013 All rights reserved, including all rights relating to the use of this document or its contents. 4. Photos Daniel Hertrich DJH: