Investor Warren Buffett's MidAmerican Energy Holdings is buying the Topaz Solar Farm, a photovoltaic farm valued at $2 billion in San Luis Obispo County, Calif. The value of the nation's solar industry has grown 67 percent, to $6 billion, since 2009, making it the fastest growing segment of the nation's renewable energy offerings. The farm will generate electricity for about 160,000 homes.
