ENERGY

* Calpine Corp., the largest U.S. operator of geothermal power plants, said it signed a contract to supply PG&E; Corp. with 400 megawatts of power starting in July. PG&E;, owner of California’s largest electric utility, Pacific Gas & Electric, will pay $51.50 per megawatt hour for the electricity, Calpine said. The contract will allow San Francisco-based PG&E; to escape some of the high prices it and other utilities paid for electricity during this year’s hottest days, it said.