Business Green: US energy giant Pacific Gas and Electric (PG&E) has this week signed a new deal with solar firm BrightSource Energy to buy 1.31 GW of solar thermal power. As part of the contract, BrightSource will build and operate seven solar power plants in the California desert that will produce 3,666 gigawatt-hours of power each year, equal to the annual consumption of about 530,000 average homes. California-based PG&E has emerged as one of the leading purchasers of solar energy in …