Its always struck me that the main problem with "renewable's" was not that this technology could produce energy, but could it produce it when we needed it? The solution to that problem is storage, if you can store energy then the dynamics of the economics changes drastically.
Well there is over 600 projects underway world wide, but one really holds a great deal of potential. Presenting Adiabatic compressed-air energy storage.
On a personal note, if you are in the market to upgrade your heating system, and save yourself money then you need a thermal store, these things are just ace. It will keep plenty of piping hot water ready for use on demand, it heats it up and it stays hot for ages. This summer with the heating off and the hot water switched off I still had warm water running through the taps two days later. And if you have a larger older property like me you always seem to get pressure problems through the taps, it is problem solved with this baby.