The future of energy

Providence Journal: Visionaries tell us that sometime in the next quarter-century we might not need polluting coal, oil and (less polluting) natural gas to supply our energy needs. We'll have environmentally benign hydrogen fuel cells to run our vehicles and keep our electrical grid humming with electrons stripped off hydrogen atoms. And we'll also have more solar and wind energy.
It's a beguiling image -- our cities as clean and fresh-smelling as the Cascades and the country finally rid of the "foreign entanglements" (goodbye, Saudi Arabia; goodbye, Venezuela) that George Washington warned of. Finally! After all, America's production peaked 30 years ago. World oil production may be peaking now.
Theorists such as Amory Lovins concede that we will still need some fossil fuel to electrolytically extract hydrogen from water. Facilities for that purpose could be in remote locations, where the hydrogen would be pressurized and then piped to buildings where fuel cells would provide heating, ventilation, air conditioning and lights, and to "hydrogen stations" for fuel-cell-powered cars.
Still, some maintain that the hydrogen economy would require a lot more energy than that. What about the fact that energy is never transferred with perfect efficiency -- that some is dissipated as heat?
Another look
Then there's nuclear energy, which is getting a new look as our energy challenge steepens -- environmentally, economically and geopolitically.
A kilogram of uranium undergoing fission produces 400,000 kilowatt hours of electricity. If it's recycled through various stages, it can produce 7 million kwh. Burning a kilogram of oil, by contrast, produces 4 kwh.
There are 104 nuclear-power plants in America, most constructed between 1970 and 1990, generating about 20 percent of our electricity. We'd need about a thousand plants to produce the BTUs that our economy consumes.
This is possible. While permitting of new plants has stagnated for the last 20 years, the technology of nuclear power has not. One thing that new plants won't have is fuel rods. The safer, cheaper "pebble bed" reactors use graphite-coated spheres of uranium the size of tennis balls.
For now, there are many questions to be resolved: What do we do with nuclear waste? What are safe levels of radiation exposure? What about the dangers of terrorism? We must answer these difficult questions, yet nuclear energy -- we would hope via fusion -- would seem at this point to be one of the keys to a great dream: a non-polluting energy future.