Yes but is still a small amount of energy relative to total demand and there don't seem to be serious efforts to scale it up massively. I don't claim to know wh

Yes but is still a small amount of energy relative to total demand and there don't seem to be serious efforts to scale it up massively. I don't claim to know why there aren't. Maybe there should be. It just makes me suspicious when I see a mature technology that still sees limited deployment, that there is a good reason for that.