Not necessarily coal-powered. While massive solar energy plants are nowhere near being competitive with coal-generated electricity, solar panels for on-site use (i.e., recharging your car at home, cooling your home, selling surplus production back to the electrical company) are going to be competitive soon. Not a solution for powering our industry, but they certainly are feasible for powering up cars overnight.
(”Overnight?” you ask. of course, I’m not talking about generating solar power at night; I’m talking about exchanging night-time-produced coal power for daytime-produced solar power, or storing solar-produced power until night.)
But will they be competitive without subsidies and with a reasonable pay back time? Last I looked, there was about a 20+ year pay back.
That old bugaboo, again?
Yeah, the utility is required to buy any surplus power you might generate, but you will be required to provide it at a certain voltage level, at a certain condition and you will be required to install and maintain protection so your surplus power doesn't screw up their network.
It requires more than a feedback loop and throwing a switch.