Actually, for steam solar plants, this problem has been addressed for a couple years already using molten sands: http://www.scientificamerican.com/article/how-t

Actually, for steam solar plants, this problem has been addressed for a couple years already using molten sands: http://www.scientificamerican.com/article/how-to-use-solar-energy-at-night/ http://www.scientificamerican.com/article/how-to-use-solar-e...