Bill McKibben’s new column in Orion magazine reports on one of the most effective ways to cut carbon emissions that we’ve got, a mature technology which stands ready to recycle enormous amounts of waste heat into electricity. It boggles my mind that we’re not doing this everywhere, instead of discussing new coal plants or nukes. Talk about low-hanging fruit!

The article centers on the fine work of the Chicago company Recycled Energy Development, piloted by frequent Gristmill contributor Sean Casten, and discusses the technology’s image problem: it’s not as sexy as wind or solar. Here’s an excerpt, but the article is so short, I encourage a quick visit to the link above:

From his desk in an office in Chicago, Jeff Smith … can, almost literally, peer down every smokestack in the nation and figure out what’s going on inside.

And what he sees is heat. Waste heat — one of the country’s largest potential sources of power, pouring up out of those smokestacks. If it could be recycled into electricity, that heat would generate immense amounts of power without our having to burn any new fossil fuels. By immense, I mean, speaking technically, humongous. Even after he’s winnowed the nation’s half a million smokestacks down to the most likely customers, that leaves twenty-five thousand stacks. “An astronomical number,” Smith says.

His boss at Recycled Energy Development, Sean Casten, leafs through the reams of data Smith has compiled. The biggest sources of waste heat are some gas turbines used to generate power, but there are endless other examples. “Let’s look at Florida,” he says. “Here’s a Maxwell House coffee roaster in Duval County. They’re roasting beans, so all that heat has to go somewhere. About twelve megawatts’ worth of potential electricity is going up the stack.” Casten could take the equipment he sells, a “waste-heat recovery boiler,” and stick it on top of the stack. “Basically, there’s a network of tubes with water in them. The heat would hit one side of it, produce steam, and we’d use that to turn a turbine and generate electricity. It’s like any other boiler, just without a flame, because the heat is already there.”

Does that sound suspiciously pie-in-the-sky? Casten can drive a few miles from his Chicago office to an East Chicago plant run by Mittal Steel. A few years ago, a predecessor energy-recycling company installed this kind of equipment on the smokestacks of the plant’s coke ovens. In 2004, this single steel plant generated roughly the same amount of clean energy as was produced by all of the grid-connected solar collectors throughout the world. Casten’s company estimates that recycling waste heat from factories alone could produce 14 percent of the electric power the U.S. now uses. If you took much the same approach to electric generating stations you could, says Casten, conceivably produce the same amount of energy we use now with half the fossil fuel.