Warren Buffett Buys World's Largest Solar Project from SunPower for $2.5 Billion
The SunPower facility has already sold its power under long-term contracts to SoCal Edison:  http://www.elp.com/articles/2013/01/antelope-valley-solar-pr...So from Buffett's perspective this just looks like a bond.  I don't think it's a bet for or against solar, but rather a bet on deferred cash vs present cash (so on interest rates).