U.S. Geothermal Inc. Advances Two Significant Development Projects

U.S. Geothermal Inc. a leading renewable energy company focused on the development, production, and sale of electricity from geothermal energy, is pleased to announce it is advancing two significant development projects. The Company's wholly owned subsidiary, U.S. Geothermal Guatemala, S.A., started drilling well EC-2 at the El Ceibillo Project today. Additionally, the Company has successfully completed a flow test program on the three largest production wells at the WGP Geysers project in northern California confirming the existence of approximately 30 MW of steam. Together, both projects have the capability of adding some 80 megawatts of electricity to the company's annual capacity

At the El Ceibillo project in Guatemala, drilling started on Well EC-2 which has a planned depth of 1,968 feet (600 meters). EC-2 will test a high temperature anomaly identified by a 2014 temperature gradient drilling program. Drilling was suspended after well EC-1 was drilled in June of 2013 until the project schedule for the concession could be modified. The Ministry of Energy and Mines approved the modified project schedule on July 21, 2015. The 8 day public comment period, which followed that approval, concluded without receiving any comments. We expect to receive the amended concession contract before the end of August.

At the WGP Geysers project, located about 1 1/2 hours north of San Francisco, in Sonoma County, the three production wells with the highest flow rates were tested. All three wells produced superheated steam with estimated flow rates at or above the rates measured when the wells were first drilled during 2008 and 2009, confirming that the wells are open and available for production. An independent, world recognized geothermal consulting firm, GeothermEx Inc., designed and monitored the flow tests, and collected test data for their analysis. The reservoir report is expected by the end of August, and will be used to guide final development of the project.

"With approximately 30 megawatts of steam drilled, tested and ready for production at Geysers, we are actively pursuing discussions in support of a power purchase agreement for this, our most advanced stage development project" said Dennis Gilles, CEO of US Geothermal. "Additionally, our geothermal concession in Guatemala holds great promise and we anticipate that the drilling results from our next few wells will allow us to confirm the geothermal resource. We expect to be able to produce from 25 to 50 megawatts of electricity when the project is completed. The government of Guatemala strongly supports renewable energy, and we look forward to continuing to work with them to make the development of this first, 100% private geothermal concession a big success."