Energy

REMEMBER OIL? We used to be strung out on the stuff, like junkies plugged into our Hummer engines. (And does anyone recall those gas guzzlers?) Now we're building carbon-free nuclear power plants and carpeting the Sunbelt with photovoltaic panels. We still use coal and oil, but we're much closer to attaining the Holy Grail of clean energy.

That, at least, is the optimist's version. Experts disagree on what will actually keep the lights on in 2020. Nuclear is poised for a comeback, though it's unlikely that by 2020 the atom will provide much more than the 8.3 percent it offers today's domestic energy market. There are lots of innovative renewable options — biofuels from pond scum? kites in the jet stream that harvest subspace winds? — but so far the race to commercial viability hasn't produced one cheap enough to compete with coal, oil, and gas. So expect more of a slog than a race in the next decade. We'll generate more renewable energy by 2020, yet it won't account for more than 10 percent of what we need, according to the National Research Council. The U.S. Department of Energy concurs — its 2010 Annual Energy Outlook forecast for 2035 actually sees gains in fossil-fuel usage.

Here's the pessimist's version: The world's thirst for oil (and our sluggish investment in alternative energy) means we will be caught short when global crude production reaches its limits — and some experts say it has already happened. That's the forecast of the Peak Oil scenario, which posits that the sharp decline in oil supplies will trigger a sudden economic collapse. "The era of happy motoring is over," says social critic James Howard Kunstler; his 2005 book, The Long Emergency, describes a grim post-oil world. Bottom line: Buy sturdy shoes, because you'll be walking a lot. "Life in the U.S.A. will become deeply local and austere," Kunstler says. Ominously, he adds, "The younger generation will punish the boomers for destroying their future."