Carlyle/Riverstone Renewable Energy Infrastructure Fund to Acquire Interest in US Renewables Group's Bottle Rock Power Corporation.

LOS ANGELES -- US Renewables Group, LLC ("USRG"), Riverstone Holdings LLC ("Riverstone") and The Carlyle Group today announced that Carlyle/Riverstone Renewable Energy Infrastructure Fund I ("CRREIF") has agreed to acquire from USRG a significant stake in the Bottle Rock Power LLC, a California-based company (Bottle Rock) whose principal asset is a 55 megawatt geothermal power station in the Geysers in Lake County. Under the terms of the convertible note and partnership interest purchase agreement, CRREIF intends to acquire an ownership stake and fund additional capital through a convertible note. This is one of the first investments from CRREIF's $685 million renewable energy infrastructure fund.

Bottle Rock plans to continue to refurbish the steam field and the facility and plans to restart the facility within the next six months. Before the end of 2007, Bottle Rock expects to produce approximately 260,000 megawatt hours per year of base load renewable power for sale to Pacific Gas and Electric under a long-term power purchase agreement. This is enough energy on average to supply electricity to over 21,000 California homes without the typical pollutants (SOX, NOX and VOCs) that result from the combustion of fossil fuels.

The Bottle Rock facility was originally constructed, owned and operated by the California Department of Water Resources ("DWR") to service its own power consumption requirements. DWR closed the facility in 1990 and subsequently sold it to several investors in 2001 who formed Bottle Rock. USRG purchased a majority stake in Bottle Rock in late 2005.

"Working with Riverstone to bring Bottle Rock back on line is a winning combination for all involved, especially the citizens of California," stated Jim McDermott, Managing Partner of USRG.

Stephen Schaefer, Riverstone Managing Director stated, "We are very excited to partner with USRG on this project. The affordable energy this project will produce demonstrates that renewable energy can and will have a growing impact on the energy mix in the U.S. and around the world."

US Renewables Group

US Renewables Group, LLC is a company organized to manage a series of private equity funds (including USRG Power and Biofuels Fund I, LP) that acquire, develop and operate renewable energy and clean fuel assets. The company owns and operates landfill methane, biomass, geothermal, ethanol and biodiesel projects. USRG also invests in the development of projects or expansion opportunities at renewable energy facilities. USRG has offices in Los Angeles and New York. For more information, please visit www.usrenewablesgroup.com.

Riverstone Holdings and The Carlyle Group

Riverstone Holdings and The Carlyle Group are the co-general partners of Carlyle/Riverstone Global Energy and Power Funds. Riverstone, a New York-based energy and power focused private equity firm founded in 2000, has $6.3 billion under management. Riverstone conducts buyout and growth capital investments in the midstream, upstream, power, and oilfield service sectors of the energy industry. Riverstone recently announced the final closing of its $685 million renewable infrastructure fund and $3.8 billion conventional energy and power fund. The Carlyle Group is a global private equity firm with $39 billion under management. Carlyle invests in buyouts, venture & growth capital, real estate and leveraged finance in North America, Europe and Asia. For more information on Riverstone Holdings or The Carlyle Group see www.riverstonellc.com and www.carlyle.com.