The agreement by investor Warren Buffett's MidAmerican Energy Holdings to buy a $2-billion photovoltaic farm in San Luis Obispo County could bring a ray of financial sunshine to the battered solar-energy industry. The scale of Buffett's foray into this sector of the renewable energy scene is considerably more modest than his $34-billion purchase of BNSF Railway, but it could provide the same kind of boost to the solar power business that the 2009 acquisition did to the railroad industry, experts said. "In a lot of ways, this is classic Warren Buffett," said Bruce Bullock, executive director of the Maguire Energy Institute at Southern Methodist University. "He comes into an industry that is starving for capital investment. At the same time, this is something that also tells people it's time to take solar power seriously."