>using surplus power to pump water up hill, to later recuperate during peak hours Consider e.g. http://www.forum-netzintegration.de/uploads/media/DUH_Sintef_B

>using surplus power to pump water up hill, to later recuperate during peak hours Consider e.g. http://www.forum-netzintegration.de/uploads/media/DUH_Sintef_Bakken_21022011_01.pdf http://www.forum-netzintegration.de/uploads/media/DUH_Sintef... >Or heating water? This is thermodynamically ridiculous. There's huge energy losses involved, cf Carnot efficiency of such a system. >From reading further, and to answer my own question, the problem is that all research in this field is geared towards the identification of materials or energy sources that can be commoditized. Oh please. It's a difficult problem. If there was an easy way to solve it cheaply without consequences it would have been done already. There are problems with dams and hot water and "layman" solutions like those. There are also problems with compressed air, batteries, and molten salts, not to mention loopy stuff like superconductors and nanosprings.