NCPA is a joint powers agency that purchases, generates, distributes, and sells electrical energy. Its members include 11 municipalities, one irrigation district, one public utility district, one port authority, and one rural electric cooperative. At the Geysers, treated effluent is being injected into NCPA's steam field that serves/supplies its two geothermal power plants.
Calpine is an investor-owned corporation that provides integrated power services, including construction, fuel supply, operations, and marketing. Calpine owns interests in a variety of power plant systems worldwide. At the Geysers, treated effluent is being injected into steam fields that serve 19 geothermal power plants operated by Calpine.