Duo pursue geothermal investments

A commitment to California’s ThermaSource by Carlyle Group and Riverstone will contribute to the development of the Bottle Rock geothermal power project.

The Carlyle Group and its affiliate Riverstone Holdings have joined private equity fund manager US Renewables Group to supply growth capital to Santa Rosa, California-based ThermaSource, a drilling, engineering and consulting services provider for the geothermal energy sector. The financial terms of the agreement were not disclosed.

US Renewables and the $685 million Carlyle/Riverstone Renewable Energy Infrastructure Fund will supply the funds to acquire new and reconditioned oil rigs, Carlyle said in a statement. The groups are making their investment through GRR Holdco, an affiliate that owns geothermal drilling rigs.

“The opportunity to partner with ThermaSource was one of the attractions in acquiring and restarting the 55 megawatt Bottle Rock geothermal power project in the Geysers,” said Tom King, a managing director at USRG Management Company. Bottle Rock Power is a California-based company that runs a 55 megawatt geothermal power station in the Geysers in California’s Lake County. The California Department of Water Resources constructed, owned and operated the facility to meet the state’s power consumption needs. It closed in 1990, but investors bought it and formed Bottle Rock in 2001.

Carlyle/Riverstone Renewable Energy Infrastructure Fund I agreed to acquire a stake in Bottle Rock from US Renewables Group in June of 2006. US Renewables bought a majority stake in Bottle Rock in 2005, US Renewables said in a June 2006 statement.

“The affordable energy this project will produce demonstrates that renewable energy can and will have a growing impact on the energy mix in the US and around the world,” Stephen Schaefer, a Riverstone managing director, said in the June statement.

Carlyle/Riverstone launched the global Energy and Power Funds in 2000 to provide capital for buyouts, growth capital and joint ventures in the energy and power industries. They joined dominion Energy Services, a developer of reneweable fuel refineries to establish a bio refinery in Alberta, Canada in November.