Storage

http://www.businessinsider.com/renewable-energy-storage-problem-2013-11

It's very easy to hype solar, which we've been doing for much of the year.Capacity is irrefutablygoing up, and prices arecollapsing.However, the absolutecapacity figures remain relatively low compared with conventional generation. And in most cases, even large-scale solar is still not cost competitive with traditional sources of electricity.There's basically one thing holding solar back: storage.Here's the problem: To run a commercially viable power plant, you need a continuous source of fuel. For run-of-the-mill power plants, this is basically not a problem — you just keep ordering up more coal, or natural gas, or uranium isotopes.