Grid energy storage remains on everyone’s minds as The New York Times’ Matthew Wald profiles SolarReserve and BrightSource’s development of molten salt storage technology for concentrated solar thermal and as details of the massive 36 megawatt hour battery storage system in Zhangbei, China continue to emerge. If wind and solar power are to take off as reliable energy generators, grid storage will be part of the equation. When the wind isn’t blowing and the sun isn’t shining, there has to be a reliable back up supply beyond costly gas generators.