Hence I said 'bulk of fossil fuels', not 'some, but leave plenty of coal behind'. In either case, the fossil fuels that are increasingly difficult / expensive

Hence I said 'bulk of fossil fuels', not 'some, but leave plenty of coal behind'. In either case, the fossil fuels that are increasingly difficult / expensive to obtain now, in an era with comparatively abundant free energy, would be even more difficult / expensive to obtain in an energy-scarce world. And yes, I'm aware that things can burn. As a species we've known how to burn things for a very long time, but the industrial revolution really only kicked off when we used coal to power steam engines. Wood - even charcoal - simply doesn't burn hot enough for much beyond food and brass. > Even dolphins would be able to develop an industrialized civilization. Well you've lost me there.