SAN LUIS OBISPO -- Most people who drive up and down on Highway 101 through California would never think of making a one-hour detour through the oak-dotted hills, canyons and ranches to visit the Carrizo Plain, a beautiful swath of land that is ringed by mountains and, in the spring, blooms with wildflowers. Yet, soon this region will be host to what will be among the largest solar power plants in the country.