Jeff Wisnia writes:

I may not be around to see it, but I'd put my money on solar energy
becoming our saving grace as solar cell efficiency gets improved and
manufacturing costs lowered.

Solar energy density is inherently weak. Physics requires it. Hoping
won't change that.

Sort of like the blood in the hospital in the movie _The Killing Fields_.
The doctors had plenty of blood, but it was spread all over the floor
instead of inside bottles.