- A new peer-reviewed study quantifies broadly for the first time the air pollution and public health impacts across the United States from both manufacturing wood pellets and burning them for energy.
- The study, said to be far more extensive than any research by the US Environmental Protection Agency, finds that U.S. biomass-burning facilities emit on average 2.8 times the amount of pollution of power plants that burn coal, oil or natural gas.
- Wood pellet manufacturers maintain that the harvest of forest wood for the purpose of making wood pellets to burn for energy remains a climate-friendly solution. But a host of studies undermine those claims.
- The Southern Environmental Law Center says the study provides new and rigorous science that could become a useful tool in arguing against the expansion of the wood pellet industry in the United States.
Forest and air quality advocates in the United States have long argued that manufacturing wood pellets from leveled forests and burning the compressed wood for energy is neither a green nor clean climate solution as biomass industry advocates have long claimed.
Now, a recent study in Renewable Energy purports to put unique, broad and scientific rigor behind arguments against the ongoing expansion of biomass production for energy. The researchers find, for the first time, that U.S. biomass facilities emit on average 2.8 times the amount of pollution as that emitted by traditional fossil fuel facilities like oil and coal. A wide range of hazardous air pollutants are emitted from burning wood pellets for energy, including particulate matter and dioxins, that are harmful to human health, the study finds.
The study finds that thousands of tons of toxic, health-harming air pollutants, from nitrogen oxide to volatile organic compounds, are also emitted in the pellet-making process, especially in the Southeast where most pellet plants are located. Researchers report that 55 hazardous pollutants collectively exceeded by two times the allowable pollution permitted by state air-quality agencies. Higher concentrations of this pollution, the study confirms, adversely impact social justice communities, or mainly poor, minority communities where the pellet plants are located.
“Fourteen million people in the United States live within a few miles of bioenergy facilities and breathe potentially harmful toxins and pollutants,” says Edie Juno, co-author of the study and a forestry specialist with the National Wildlife Federation in Washington, D.C. “As the bioenergy market continues to grow globally, it is critical that we understand the impacts and costs of utilizing biomass for energy.”
Juno confirms that burning these pellets overseas — in the EU, U.K., Japan and South Korea — also leads to hazardous pollution. In the U.S., where burning forest biomass makes up only 1.3% of overall U.S. energy generation, it contributes about 3-17% of all energy pollutant emissions, according to the new study.
“If … the U.S. increases the share of bioenergy as it reduces the share of fossil fuel energy in its mix,” the study notes, “emissions from bioenergy could present greater concerns to public health.”
Saravanan Arunachalam, co-author and deputy direct of the Institute for the Environment at the University of North Carolina at Chapel Hill, adds, “For too long, the impacts of bioenergy and wood-pellet production on air pollution have been under-researched.”
He tells Mongabay that the study, which in essence compares state-granted pollution permits with actual emissions, is significantly more comprehensive than anything produced by the U.S. Environmental Protection Agency (EPA).
“The EPA inventory [to track similar bioenergy impacts] included 38 facilities,” Arunachalam says, “but as we found from various sources, 153 plants were issued permits across the country for manufacturing and burning.”
A growing U.S. presence
Currently, the European Union relies far more heavily on forest biomass for energy production. There, it makes up 60% of the EU’s so-called renewable energy mix.
“I don’t think we’re in a giant energy transition in the U.S. from fossil fuels to biomass,” Juno says. “But new bioenergy plants are being proposed in California and other regions of the country. Policymakers need to know this is counterproductive to our clean energy and carbon reduction goals, and also to our goals around human health and well-being.”
Juno’s concerns over an expanding US biomass industry are already beginning to play out. The U.S. Forest Service announced in June 2023 around $10 million in grants in support of a range of startup biomass-burning projects in states such as Alaska, California, Washington, Colorado, Kentucky, New Hampshire and Virginia.
Environmental and social justice groups have also sought to bring attention to lobbying efforts to the U.S. Congress by two of the world’s largest wood pellet manufacturers, Enviva and Drax.
Both companies, which collectively operate more than a dozen facilities in the U.S. Southeast, continue to seek the kinds of U.S. taxpayer subsidies that have fueled their growth overseas. Both the EU and the United Kingdom have spent billions in public money to convert scores of coal-burning energy plants to burn wood pellets instead.
Industry claims climate benefits
Representatives with the U.S. Industrial Pellet Association did not respond to requests for comment. But its website is filled with content that describes “a growing body of scientific literature [that] confirms the US biomass industry is achieving carbon-neutrality, a key requirement for reducing emissions and mitigating climate change.”
The association argues that the cut forests regrow over time, sequestering the emitted carbon. This is why the industry argues — and many government policies agree — that burning wood pellets is carbon neutral and thus a better climate-mitigating choice than burning coal.
But an oft-cited 2018 study from the Massachusetts Institute of Technology found that carbon neutrality after clear-cutting takes 44-104 years, assuming the forest is allowed to regrow and is not cut again in the meantime. Meaning, once cut, these regrowing forests should be left alone until the 2120s. This goes against the United Nations assertion that we must reach global carbon neutrality within about 25 years to stave off the worst impacts of climate change.
In addition, Enviva and Drax contribute to the clear-cutting of hundreds of acres per month of native forests across the Southeast to produce roughly 10 million metric tons of wood pellets annually for export overseas to the U.K., EU and Asia.
“Assuming biofuels are carbon neutral may worsen irreversible impacts of climate change before benefits accrue,” MIT researcher John Sterman wrote as part of the 2018 study.
In the new study, UNC researcher Arunachalam says his team does not address the issue of carbon neutrality but says, “Making and burning wood pellets is certainly not health neutral.”
A new tool for air quality advocates
In the new study, researchers inventory the states with the highest concentrations of toxic pollutants in the air due to wood pellet production and burning. Those U.S. states are in the Southeast: Mississippi, Georgia, North Carolina, Alabama, Louisiana and Virginia — where Enviva and Drax plants are located.
In 2021, Mississippi fined a Drax-owned plant in the state $2.5 million for violating hazardous emissions limits. North Carolina also cited one of its Enviva plants at least five times for air pollution violations, though the fines were minimal.
Patrick Anderson, a staff attorney with the Southern Environmental Law Center in Atlanta in its clean air program, calls the study a new, credible and comprehensive tool in SELC’s mission to oppose the expansion of wood pellet making and burning in the United States.
“I spend a lot of time with this kind of data,” Anderson tells Mongabay. “If you used the EPA National Emissions Inventory and you wanted to know how much pollution all the wood power plants in the country emitted, you just couldn’t do it. You could get close, but the data set would be incomplete and very limited with plenty of blind spots.”
Anderson says he wasn’t surprised by the study’s bleak findings, but it will be a useful and rigorous “tool” in arguing against incentivizing the expansion of the biomass industry in the U.S.
In 2023, U.S. wood pellet exports were up 6% through September over 2022’s record shipments, according to the U.S. Department of Agriculture. Despite known environmental drawbacks, demand for wood pellets remains high across the EU, U.K., as well as Japan and South Korea.
Whether Enviva, the world’s largest maker of wood pellets, can continue to meet that demand remains in question. The company lost hundreds of millions of dollars last year due to machinery failures at many of its plants, high maintenance costs and rising wood costs. Management warned investors in November that it may not be able “to continue as a going concern.”
Anderson says if Enviva fails, the new study could become useful for the SELC or other forest advocates in arguing against any new pellet manufacturer receiving federal, state or local subsidies to take over and repair Enviva’s plants to produce the tons of pellets Enviva has been making for years..
Banner image: A wide range of hazardous air pollutants are emitted from burning wood pellets for energy, including particulate matter and dioxins, that are harmful to human health. Image by Oregon Department of Forestry via Flickr (CC BY 2.0).
Justin Catanoso, a regular contributor, is a professor of journalism at Wake Forest University in North Carolina.
Tran, Huy; Juno, Edie; Arunachalam, Sarav (2023) Emissions of wood pelletization and bioenergy use in the United States. Renewable Energy. https://doi.org/10.1016/j.renene.2023.119536
Sterman, John, et al (2018) Does replacing coal with wood lower CO2 emissions? Dynamic lifecycle analysis of wood bioenergy. Environmental Research Letters. 13 015007 DOI 10.1088/1748-9326/aaa512