National Public Radio: California Gov. Arnold Schwarzenegger has set an ambitious plan that requires a third of the state’s electricity to come from renewable sources by 2020. But a fight over where to build large clean-energy projects is slowing the green revolution. One of these battlegrounds is Panoche Valley, ringed by rolling, scrub-covered hills. Located in California’s rural San Benito County, the area was used mostly for cattle grazing, and it has escaped the notice of many Californians. Until …