Commonwealth Energy is to purchase power from the Geysers geothermal power plants owned by Calpine Corp under a recent deal. Commonwealth supplies electricity to 50 000 customers throughout California.

The deal follows the acquisition of the 14 Geysers plants by Calpine from Pacific Gas and Electric. Commonwealth will initially purchase 60 MWe of power during 1999, increasing the capacity to 100 MWe in 2000 and 125 MWe in June 2002.

The power will be sold at a fixed price which increases each year. Calpine expects to earn $90 million over the lifetime of the deal. The Geysers geothermal field supports a total of 1000 MWe of geothermal capacity.