>> We are basically drenched in free energy, but we can't store it cheaply enough. If that's fixed, we're done here.
I think that's a simplistic view. Yes there is tremendous energy in the movements of air in the atmosphere, and water in the seas, even more in the daily exposure to sunlight, and quite a bit in the geologic forces operating in the earth's interior. That's all well and good, but what matters in terms of powering a modern civilization is energy density, portability, and durability. Electric power isn't going to get a lot more portable than it is now. Storage improvements will make it more durable. But in terms of density the only sources we have are heat cycle sources dependent on fossil and nuclear fuels. Storage advances don't magically make renewable sources dense enough to replace the power we now get from non-renewable sources.
Edit: I should also have mentioned the obvious non-heat cycle source, hydro, which is dense enough in some places to be a very significant contributor.
This is entirely correct and always forgotten by the 'energy is everywhere, we just have to grab it' thinking.
The point is that wind energy is too diffuse and the capital costs of tying up that much land in wind generators is astronomical - and there is a very real degradation in site quality as you use up all the good sites first. It's pointless to say it's always windy somewhere, because transmission losses and costs make that unfeasible.
Solar is even worse because at even the best site on the best day you only get 50% of energy generation time, so event with perfect storage you have to have 2x the generation capability.
All this is the reason why - even right now with massive subsidies and compensation and special protection from environmental standards other developments have to adhere to - wind and solar account for about 1% of worldwide energy generation.
There is a limited role of grid top-up for solar and wind, but the future of energy generation is not either of them. The near term is in more efficient and less polluting modern gas and coal plants, with conventional nuclear filling increasing in use to provide clean energy without airborne pollution.
If the public can ever get over three decades of nuclear hysteria, that is.
I think that's a simplistic view. Yes there is tremendous energy in the movements of air in the atmosphere, and water in the seas, even more in the daily exposure to sunlight, and quite a bit in the geologic forces operating in the earth's interior. That's all well and good, but what matters in terms of powering a modern civilization is energy density, portability, and durability. Electric power isn't going to get a lot more portable than it is now. Storage improvements will make it more durable. But in terms of density the only sources we have are heat cycle sources dependent on fossil and nuclear fuels. Storage advances don't magically make renewable sources dense enough to replace the power we now get from non-renewable sources.
Edit: I should also have mentioned the obvious non-heat cycle source, hydro, which is dense enough in some places to be a very significant contributor.