Like most things electronic, solar power has been getting cheaper. "Thirty years ago it was cost-effective on satellites," says Daniel Shugar, president of PowerLight Corporation, a fast-growing California company that has built solar installations for clients including Toyota and Target. "Today it can be cost-effective for powering houses and businesses," at least where utility power is expensive or unavailable. Tomorrow, he says, it will make sense for almost everyone. [...]
At present levels of efficiency, it would take about 10,000 square miles (30,000 square kilometers) of solar panels—an area bigger than Vermont—to satisfy all of the United States' electricity needs. But the land requirement sounds more daunting than it is: Open country wouldn't have to be covered. All those panels could fit on less than a quarter of the roof and pavement space in cities and suburbs.
We want to repeat that this is at current efficiency. It is bound to get higher, especially since it's already being done experimentally in the lab.
There is more on wind, biomass, nuclear and fusion in the article. Go read it, it's well written, mostly accurate, and informative if you aren't already familiar with energy issues. A good introductionary piece to forward to friends and family members.