[lelio]

how it might supplement utility-based electricity with wind and solar energy
Wind energy? Someone must have a state in a windmill production plant or have some land they want to sell to the government.

The plant would extract nonpolluting hydrogen from water, and the hydrogen could be used to generate electricity or to power fuel cells for motor vehicles. The carbon dioxide produced as a waste would be captured and sequestered underground.
And how do you seperate the hydrogen from oxygen and then cramp that hydrogen into a fuel cell? Why, by burning coal to make electricity! I'm not sure where the enviro wackos got the idea that a "fuel cell" is something more than a battery. Granted, it could make the environment in which the fuel cell is used cleaner.
And store the CO2 underground? Give me a break.

[mvpel]

And store the CO2 underground? Give me a break.

As long as you don't store it under Yucca Mountain!