Sierra Geothermal Power Corp.
TSX VENTURE : SRA

Sierra Geothermal Power Corp.

October 22, 2007 06:01 ET

Sierra Geothermal Power Commences Drilling at Reese River

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Oct. 22, 2007) -

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Sierra Geothermal Power Corp. (SGP) (TSX VENTURE:SRA) is pleased to announce it has commenced drilling of a deep temperature gradient well at its Reese River site in Lander County, Nevada.

The well is intended to provide additional information on the reservoir characteristics prior to drilling the first production assessment well. The temperature gradient well is planned to be the deepest well drilled on the property to date. The drilling permit allows a maximum depth of 1,829 meters (6,000 feet).

"Exploration drilling to date has produced encouraging results, and we are excited to begin this new deep phase of drilling," said Gary Thompson, President and CEO of SGP.

About Reese River

SGP announced drilling results in the May 16, 2007 news release from the Reese River exploration well 56-4. The exploration well was drilled on the southeast flank of the thermal gradient anomaly and was designed to test the reservoir characteristics. Independent consultants, GeothermEx Inc., have provided a preliminary evaluation of the exploration results as follows: Temperatures of at least 124 degrees Celsius (256 degrees Fahrenheit) were detected in Well 56-4 which was drilled to 1,198 m (3,930 feet), confirming the evidence from shallow drill holes that a significant geothermal anomaly is present at drillable depths.

The Reese River project was rated by Richards and Blackwell as one of the top 15 undeveloped geothermal prospects in Nevada. Phillips Petroleum and Amax Exploration drilled 52 temperature-gradient holes during the 1970's and 1980's. Contoured data of the temperature-gradient wells outline a 150 degrees C/km heat-flow anomaly that is approximately 4.8 km (3.0 miles) long in the northeast direction by approximately 1.6 km (1.0 mile) wide. The center of the anomaly reaches a temperature gradient of over 500 degrees C/km with an overall average of 225 degrees C/km. The maximum calculated heat flow at Reese River is 1,117 MW/m2. Using a Monte Carlo simulation, the potential geothermal resource at Reese River was estimated to have a 90% probability of generating 13 MW and a 50% probability of exceeding 30 MW. A 30 MW power plant can produce enough electricity to power 24,000 homes.

About Sierra Geothermal Power Corp.

SGP is a Vancouver-based renewable energy company focused on the exploration and development of clean, sustainable geothermal power. Geothermal power plants produce long-term revenues and provide continuous base-load power, often at or above 95% capacity. SGP's 17 projects comprise a total of 88,000 acres of geothermal land assets in Nevada and California. The company intends to advance the development of its portfolio of projects through a combination of equity and/or joint ventures, while continuing to evaluate additional acquisitions. To find out more about Sierra Geothermal Power Corp. (TSX VENTURE:SRA), visit our website at www.sierrageopower.com.

Any failure to comply with this restriction may constitute a violation of United States securities law. This news release contains forward-looking statements that are subject to certain risks and uncertainties that may cause actual results to differ materially from those projected on the basis of such forward-looking statements. Such forward-looking statements are made based upon management's beliefs, as well as assumptions made by, and information currently available to, management pursuant to the "safe-harbor" provisions of the Private Securities Litigation Reform Act of 1995.

The TSX Venture Exchange does not accept responsibility for the adequacy or accuracy of this release.

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