The Freestone Energy Center is a natural gas-fired combined-cycle facility located on approximately 506 acres near Fairfield, Texas.  The plant was Calpine’s first facility built in the northern part of the Texas Regional Entity market area.  The Freestone Energy Center consists of four combustion turbines, four heat recovery steam generators and two steam turbine generators, configured in two largely independent power blocks. 

In December 2010, Calpine sold a 25% undivided interest in the Freestone Energy Center to Rayburn Country Electric Cooperative, Inc., which provides the wholesale power requirements for five rural electric distribution cooperatives.  Additionally, the plant generates electricity sold into the ERCOT market.  It interconnects to the Oncor transmission system. 

In 2009, the plant was granted Bronze-level membership status in the Clean Texas Program, sponsored by the Texas Commission on Environmental Quality.  Clean Texas provides recognition for companies that serve as leaders among Texas workplaces that seek to achieve significant environmental results, create environmental awareness and protect air, water and land resources in Texas.