Perhaps the most amazing part of the process is that it’s self-sustaining. Just like your toaster, Startech’s Plasma Converter draws its power from the electrical grid to get started. The initial voltage is about equal to the zap from a police stun gun. But once the cycle is under way, the 2,200˚F syngas is fed into a cooling system, generating steam that drives turbines to produce electricity. About two thirds of the power is siphoned off to run the converter; the rest can be used on-site for heating or electricity, or sold back to the utility grid. “Even a blackout would not stop the operation of the facility,” Longo says.
It all sounds far too good to be true. But the technology works. Over the past decade, half a dozen companies have been developing plasma technology to turn garbage into energy. “The best renewable energy is the one we complain about the most: municipal solid waste,” says Louis Circeo, the director of plasma research at the Georgia Institute of Technology. “It will prove cheaper to take garbage to a plasma plant than it is to dump it on a landfill.” A Startech machine that costs roughly $250 million could handle 2,000 tons of waste daily, approximately what a city of a million people amasses in that time span. Large municipalities typically haul their trash to landfills, where the operator charges a “tipping fee” to dump the waste. The national average is $35 a ton, although the cost can be more than twice that in the Northeast (where land is scarce, tipping fees are higher). And the tipping fee a city pays doesn’t include the price of trucking the garbage often hundreds of miles to a landfill or the cost of capturing leaky methane—a greenhouse gas—from the decomposing waste. In a city with an average tipping fee, a $250-million converter could pay for itself in about 10 years, and that’s without factoring in the money made from selling the excess electricity and syngas. After that break-even point, it’s pure profit.
Someday very soon, cities might actually make money from garbage.single page
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.