If you want to see why solar by 2015 will be as big as shale, take a look at solar pricing in Arizona. Arizona has a virtually unmatched solar resource and is reaping low solar power prices already. New utility scale solar facilities are generating solar at 10 cents per kilowatt-hour. http://planetark.org/wen/63601. That price includes no tax credits or any subsidies.
Electricity rates of 12 to 18 cents per kilowatt-hour are common from California to Maine so solar at 10 cents will be attractive just on economics alone for many consumers. Hawaii which still depends on expensive and dirty oil for a lot of electricity has had rates from 20 to 30 cents per kilowatt-hour.
The 2011 Arizona solar price has fallen sharply from 14 to 16 cents per kilowatt-hour in 2010. The lower prices are leading to a solar boom in Arizona that will install 240 megawatts of solar this year, according to Suntech, a major solar company.
But the key is not today's 10 cents solar price but the continuing price declines. Those continuing price declines will make solar as big an energy event as shale gas is today.