I think your experience typifies the real situation with batteries. All the basic ideas are known and every one has been progressed to the point where its been discarded for one reason or another.
The renewable dream is kept alive on the one hand by the faith of those who want it to work, and on the other by the cynicism of those who don't care if it works as long as the public purse is raided to pay them for it.
The smart money is leaving the renewable energy industry in droves -
30% fall in the sector in the latter half of this year.They will both turn to nuclear power, once every other alternative has been explored.