Here’s a green riddle for you: if a tree falls in the forest and it’s chipped, then shipped to be burned for electricity, is it carbon neutral?
It’s a question that’s been tripping up national carbon calculators around the globe since the days of the Kyoto Protocol. From the late 1990s, industry and governments have largely considered burning wood pellets in power stations to be renewable, zero-emitting energy, since planting new trees should, theoretically, absorb enough carbon dioxide to cancel out the emissions that come out of smokestacks as they burn.
But doubts regarding the science behind those claims and the sustainability of the practice have been mounting as more countries ramp up the burning of woody biomass as a replacement for coal.
In October, the world’s largest biomass-burning power generator, Drax Group, was one of 15 companies booted off the S&P Global Clean Energy Index. S&P also ditched the French bioenergy firm Albioma. The reason given: their “carbon-to-revenue footprint” was too large. S&P didn’t offer company-specific details beyond that, saying only that changes to the S&P Global Clean Energy Index were integrated “in order to enhance index diversification, improve transparency, further reduce the index’s carbon footprint, and align the index methodology with market trends and sustainable investing norms.”
That same month, a study led by Princeton University, published in the journal Science, called out a “serious” error in the climate accounting rules widely applied to biomass energy since the Kyoto Protocol. “This accounting erroneously treats all bioenergy as carbon neutral regardless of the source of the biomass.... For example, the clearing of long-established forests to burn wood or to grow energy crops is counted as a 100% reduction in energy emissions despite causing large releases of carbon.
“Burning wood to produce energy can actually worsen climate change, at least through the year 2100 – even if wood displaces coal, the most carbon-intensive fuel.”
–John Sterman, MIT
The carbon-neutral assumption might be true if you’re using perennial grasses or twigs, but scientists say that tree plantations don’t store as much carbon as natural forests, and regrowth takes time. It could take 40 to 100 years for planted trees to absorb the carbon debt released by biomass power plants (in boreal forests those estimates jump to 100 years).
Back in 2018, MIT scientist John Sterman concluded that “burning wood to produce energy can actually worsen climate change, at least through the year 2100 – even if wood displaces coal, the most carbon-intensive fuel.” In early 2021, the European Academies’ Science Advisory Council affirmed that using woody biomass for power “is not effective in mitigating climate change and may even increase the risk of dangerous climate change.”
Meanwhile, the carbon accounting loophole has fuelled a boom in the biomass industry in Europe, the U.S., Canada and the U.K., where it’s highly subsidized. In the EU, biomass accounts for about 59% of all renewable energy consumption.
Once the largest coal generator in western Europe, Drax now gets two-thirds of its biomass from southeastern U.S. forests and a growing percentage from western Canada. Last April, Drax purchased British Columbia’s Pinnacle Renewable Energy, which the company says should increase its annual operational capacity to 4.9 million tonnes of biomass pellets by 2022, up from 1.6 million tonnes. Drax now owns more than half the pellet mills in B.C.
Pellet makers generally say they don’t cut down whole trees and instead use fallen branches, sawdust and other waste wood, but environmental organizations in both the U.S. and Canada say otherwise. The Natural Resources Defense Council has said that “multiple independent investigations show that wood sourced from clearcuts of mature and biodiverse forests routinely enters Drax’s supply chain.”
Drax says that its biomass meets the “highest sustainability standards” and that, in B.C., “harvesting increased significantly to utilise the dead and dying timber [affected by mountain pipe beetle] as lumber in sawmills whilst it was still viable.”
Ben Parfitt, a researcher with the Canadian Centre for Policy Alternatives (CCPA), takes issue with the statement. “Photographs, videos and publicly available data clearly show that Drax doesn’t discriminate between living or dead trees. It takes whatever it can get its hands on,” says Parfitt, who wrote an investigative report on the pellet industry in April. He adds, “It’s time the B.C. government commissioned an independent expert to investigate.”
Until then, CCPA is calling for a ban on any new pellet mills in the province. The Vancouver-based environmental group Stand.earth has called for a moratorium on the logging of B.C.’s primary forests for pellets. Across the pond, 50 MPs wrote a joint letter to Britain’s energy minister in December, calling the burning of wood to create power a “scandal.”
Drax maintains that its bioenergy has slashed its CO2 emissions from power generation by more than 90% since 2012. The firm is looking into piloting carbon-capture technology, which CEO Will Gardiner says will make the company carbon-negative by 2030.
