The US throws out 250 million tons of garbage a year. Roughly a third is recycled, and the rest is landfill. You might think that’s a problem. But one man’s trash is another’s treasure. Oslo, Norway burns rubbish to power and heat homes, and they’ve run out. The city imports trash from Sweden, Ireland, England—and they wouldn’t mind taking on a few tons from the US.
And it’s not just Oslo. Northern Europe’s trash burning capacity outstrips its trash producing capacity by 550 million tons. Neighboring Sweden imports 800,000 tons of trash annually to make energy. Norway, Austria, and Germany are also getting in on the game. In total, 40 countries worldwide burn trash for energy.
At first blush, burning trash sounds like just about the dirtiest way to produce energy. But Europe, particularly the northern part, is known to be environmentally conscious. So what gives? While modern trash incineration isn’t Mr. Fusion, it’s light years from a smoldering pile of refuse in your neighbor’s backyard.
Waste-to-energy plants burn trash at temperatures reaching 2,000 degrees Fahrenheit. The inferno turns water to steam and runs turbines to produce electricity. The trash is separated into ash and flue gases. Metals, acids, and other toxic chemicals are removed from the gas through a series of filters, leaving only CO2 and water vapor. The ash—still toxic but volume much reduced—is carted off to line landfills.
American waste-to-energy plants burn 29 million tons of trash for energy each year (11.7% of the total), but there tends to be more pushback in the US than in Europe. This is in part due to incineration’s unclean past. Prior to the 90s, it was a filthy process. Meanwhile, today’s industry markets itself as a renewable source of energy—a line that makes some opponents bristle.
Critics point out the ash is still toxic and the filtered gas still contains the greenhouse gas CO2. The question is whether the amount of CO2 released by waste-to-energy plants has a greater impact than the methane—a gas that traps more heat than CO2—that would have been released in landfill. The industry claims the process compares favorably, while environmentalists question the numbers.
Then there’s the other half of the argument. Labeling waste-to-energy as renewable competes with other favored strategies like wind and solar. And shouldn’t we focus on recycling more stuff, instead of just burning it? It takes less energy to repurpose already constituted industrial materials than building them up new—plus, it saves resources.
Although waste-to-energy may not be a long-term energy solution and shouldn't replace recycling, maybe it makes sense as an alternative to landfill.
As Chief Sustainability Officer at US waste-to-energy provider Covanta told Scientific American, “We have the same waste hierarchy as the EU: reduce, reuse, recycle, energy recovery and disposal. [This] is that step we call the 'fourth R.' After you reduce, reuse and recycle that, you take the step of energy recovery before you put it in the ground."