Free energy wont happen as long as people can make money on electricity. Also do you not see the catch 22 heere? In order to make Bitcoins you need electricity (yeah there are solar panels but how many use it?).
Can you name some of the technical innovations that BTC has made, if we look away from decentralizing part?
Maybe the security (cryptography) , and also the lowest fee ( but this is not an innovation, it is only a comfort).