Californian utility PG&E has expanded an already huge purchase agreement with BrightSource from 900 megawatt of solar thermal power to 1,310 megawatts. BrightSource CEO, John Woolard, said that makes it “the largest solar deal in the world”. Previously, the largest solar contract was for 1,300 megawatts to be supplied by Brightsource to Southern California Edison.

The new deal is for power purchases over 20 years from seven solar thermal projects that will be built in the Mojave desert. The power plants will consist of thousands of sun-tracking mirrors which will focus the sun’s rays on a water-filled boiler sitting on top of a tower. The heat will produce steam to drive a turbine to generate electricity