Slate: “Among other things, COP26 failed to address biomass energy, which many European nations have relied on as a “renewable energy” source. At best, that terminology is a semantic stretch. At worst, it’s greenwashing a dirty fuel at the worst possible moment. One thing is for certain: Biomass has fueled quite the controversy.
Biomass energy comes from organic material like waste crops and animal manure—but it’s mostly wood burned in the form of compressed particle pellets. It’s not super common in the U.S.: According to U.S. Energy Information Administration statistics, biomass energy (again, mostly made from wood) represented roughly 5 percent of total domestic primary energy use during 2020. But the Build Back Better Act passed by the House of Representatives would support increasing its use. It’s already more common across the Atlantic: Biomass energy is the second-largest source of renewable electricity in the U.K., having provided 12 percent of its electricity in 2020. Woody biomass accounts for more than half of the European Union’s renewable energy sources. And a lot of that wood is coming from the Southeastern U.S.
…Companies like Enviva—which boasts on its website to be the “world’s largest producer of sustainable wood pellets”—also claim to use only low-value wood and waste products from the timber industry, like tree limbs, mill residues, and the products of forest thinnings. In response to critiques that biomass producers use full trees as well, Enviva’s chief sustainability officer, Kim Cesafsky, says it is true that the company often uses “roundwood form,” which is just an industry term for wood left as logs. However, Cesafsky and Enviva argue they only use roundwood that wouldn’t go to market in other industries. “It will look like it has a pretty big butt on it. It’s either because it had a big crook in it or it was rotten in the middle and there’s no other place to sell that material. … without an outlet for it, it impedes regeneration and is something that landowners will have to pay to get off their property,” she told me. According to the company’s sustainability report, this market “encourages good forest stewardship and creates incentives for forest landowners to replant and keep their land as forest.” And Enviva officials repeated a line from their company’s website, noting that the number of trees in U.S. forests have increased every year over the past 50 years.
…However, further investigation doesn’t support this overly rosy view. Research suggests that burning woody biomass requires decades of regrowth to recoup its carbon debt (time being something we have very little of in the climate crisis)—and that the replanting of hardwood forests with fast-growing pines for biomass purposes actually decreases the carbon density of wooded areas. (While Enviva is right that forest land has increased in the U.S. Southeast, its carbon uptake has decreased at the same time.) In fact, in the short term, burning wood might be worse for greenhouse gas emissions than coal—especially given that wood burning is wildly inefficient. Not only is biomass energy generally more expensive to produce per megawatt hour, but, as the British policy institute Chatham House further explains, wood is simply less energy-dense than other carbon-emitting fuels. To make efficiency matters worse, methods to make the fuel more efficient lead to greater environmental harm. And that’s not even counting the fuel for the boats that transport trees to biomass facilities across the world. Or the noise and pollution stemming from the production facilities that process wood into pellets. Wood pellet plants emit pollutants like carbon monoxide and particulate matter into the air.”