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2013 Project Report

Summarized Schedule of Activities Fall 2013

Weekly Updates

Photos

Pilgrim Hot Springs is the hottest resource in the state not directly associated with a volcanic system. It has a lengthy history of local use, and is currently listed on the national historic register. This project involves testing and verifying an innovative remote sensing technique developed by researchers at
UAF’s Geophysical Institute. This technique, based on aerial infrared imaging, was originally used to map underground coal fires and subsurface movement of magma. However, by creating an accurate estimate of the natural heat flux at the surface from a geothermal resource, it also has the potential to significantly reduce the cost of geothermal exploration for low and moderate temperature geothermal sites, especially those located in inaccessible areas.

By testing and verifying this technique at the Pilgrim Hot Springs site and locating the source of the geothermal water, ACEP can assess the feasibility of various options for developing this site to benefit the region and its residents.

Pilgrim Hot Springs is located 60 miles northeast of Nome on the Seward Peninsula along the western coast of Alaska. The proximity of this geothermal resource to Nome as well as other communities and identified mineral resources in the region make this study of significant interest, as geothermal energy is one of the few renewable resources capable of providing reliable, baseload power comparable to diesel-based generation.

ACEP and its partners have successfully completed three seasons of fieldwork beginning with an airborne FLIR (forward looking infrared) survey conducted in 2010, and repeated in 2011. This was followed by ground-based and aerial geophysical surveys, as well as a drilling program which resulted in a total of 60+ shallow gradient holes of depths ranging from 80 to 500 ft, as well as 3 deeper confirmation holes that drilled to bedrock and were used to locate the source of the thermal fluids.

Through this exploration program, particularly the FLIR aspect, our team was able to expand the extent of the known thermal anomaly from the immediate area around the hot springs, to a much larger feature with surface expressions visible up to 2 miles from the main resource. Additional high thermal gradients reported by a graphite mining operation drilling exploration holes 10 miles to the mwest of Pilgrim Hot Springs further supports the idea that the deeper system may be much larger than previously estimated.

Today we know that the available heat from Pilgrim Hot Springs is approximately 20MWth, with maximum downhole temperatures of 195°F, though the estimated reservoir temperature is considerably higher – likely approaching ~300 °F. This means the resource could be capable of sustaining approximately 2 MW of power generation, which could be used locally or delivered to Nome or a nearby mining operation via a transmission line.

ACEP is recommending the drilling and testing of an additional, large-diameter well capable of producing up to 2000 GPM and sited near the upflow zone. By using the existing holes as monitoring sites during a pump test, we can collect data while stressing the resource and monitor how it responds. This will allow us to improve our model and refine a strategy for site development. This drilling program would require additional funding to complete

This project is a collaborative research effort between ACEP and the Geophysical Institute (UAF).

Project Funding Partners

• Department of Energy Geothermal
• Technologies Program
• Alaska Energy Authority -
• Renewable Energy Fund

Project Research Partners

• Unaatuq, LLC
• Mary’s Igloo Native Corporation
• Bering Straits Native Corporation
• United States Geological Survey (USGS)

A special thanks to our industry advisory committee for providing input and guidance throughout this project, and to all of our community and utility industry partners.