Calpine will sell a 25% undivided interest in the 1,038MW Freestone Energy Center in Texas, US, to Rayburn Country Electric Cooperative for $215m.
Calpine remains the majority owner and will continue to operate the plant in exchange for annual operating and management fees from Rayburn.
Rayburn will receive 25% of the economic benefit of the plant's output, allowing it to better serve its customers in rural north and east Texas.
The combined-cycle natural gas-fired power plant began commercial operation in June 2002.
The Freestone plant generates power first through four electricity-producing natural gas turbines, and then uses heat from the process to create steam to drive two steam turbines.
This fuel-efficient approach allows Calpine to reduce emissions compared with older fossil-fuel facilities.