AltaRock Energy Inc, the California based Geothermal energy company, has announced today it closed a $26.25 million second round of financing that will fund the development and demonstration of technology designed to lower the cost of Engineered Geothermal System (EGS) electricity generation. The funding is coming from the company’s first-round investors, Khosla Ventures and Kleiner Perkins Caufield & Byers, who are joined in this round by Google.org, Advanced Technology Ventures, and Vulcan Capital.

AltaRock CEO Don O’Shei said, “The company could not be more excited about what this financing, being made by such a knowledgeable group of investors, means for us and for the future of renewable energy. The successful implementation of EGS generation will resolve many problems that have slowed the full adoption of environmentally attractive energy solutions.”

AltaRock intends to develop EGS in a cost-effective manner in order to provide baseload renewable energy to U.S. power markets, and to meet the renewable portfolio standard needs of utilities in states such as Washington, Oregon, California and Nevada. AltaRock Energy’s planned EGS demonstration project will test the company’s proprietary technology advancements that are expected to reduce the costs of engineering geothermal fluid flow paths in hot rock. AltaRock has filed applications for a portfolio of U.S. patents in the EGS area, and holds exclusive U.S. licenses for other related intellectual property. Several development projects are expected to follow the demonstration of this technology.

Geothermal energy is clean, renewable energy that offsets CO2 emissions of electricity generated from fossil fuels such as coal and natural gas. Typically geothermal plants generate electricity 24 hours a day, seven days a week.

Emerging EGS technology has the potential to facilitate geothermal development in areas across the country that do not have conventional geothermal resources. EGS also has the potential to reduce the “dry hole” risk associated with conventional hydrothermal development, which requires locating existing fractures containing high flows of hot water. EGS projects produce electricity using heat extracted with engineered fluid flow paths in hot rock. In the first portion of the EGS power generation cycle, a fractured reservoir is created at a depth where the rock is hot. Water is continuously injected down a well into the engineered fractures that then heat up the water as it flows through. The water is then brought to the surface via production wells, and its heat is extracted to generate electricity in power plants. Finally, the water, depleted of its heat, is re-injected to be heated again.