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Burning forests to make energy: EU and world wrestle with biomass science

  • A major political and environmental dispute is coming to a boil in the run-up to COP26 in Scotland this November, as the EU and the forestry industry push forest biomass (turning trees into wood pellets and burning them to make electricity), claiming the science shows biomass is sustainable and produces zero emissions.
  • Forest advocates and many scientists sit squarely on the other side of the argument, providing evidence that biomass burning is destructive to forests and biodiversity, is dirtier than coal, and destabilizing for the climate. Moreover, they say, the carbon neutrality claim is an accounting error that will greatly increase carbon emissions.
  • These views collided in July when the European Commission called for only minor revisions to its legally binding Renewable Energy Directive (REDII) in regard to biomass policy as part of the EU Green Deal. Critics say the plan, if approved by the EU Parliament in 2022, will fail to protect global forests from the wood pellet industry.
  • Here, Mongabay offers a review of the science on both sides of the biomass debate, summarizing key studies and reports, and providing links to primary sources for enhanced insight into these complex issues. The EU decision to include wood pellets as part of its clean energy mix could help shape global biomass policy at COP26.

Mongabay published an earlier version of this story July 12, 2021. This version of the article contains significant new reporting.

The European Commission won widespread praise in July when it released details fleshing out its climate change mitigation plan as part of the European Union’s Green Deal. The announcement highlighted pathways by which the 27-nation bloc plans to cut its carbon emissions 55% by 2030 over a 1990 baseline, with carbon neutrality achieved by 2050 — making Europe the first continent to do so.

Taking this step, the EU is clearly positioning itself for a global leadership role in the run-up to the United Nations COP26 climate summit scheduled for November in Scotland, when more aggressive national commitments to reduce emissions made since the 2015 Paris Agreement will finally be put into action.

The EU in July modeled to the world what it sees as aggressive climate action: a roadmap that includes a phaseout of fossil fuels used to produce energy in nine years; a ban on the production of gas- and diesel-powered vehicles by 2035; a tax on carbon-intensive imports; and a requirement that 38.5% of all energy come from renewable sources by 2030 (it’s already at 38%). European Commission President Ursula Von Der Leyen has defined the European Green Deal as “Europe’s man on the moon moment.

Thousands of whole trees form a ring at Enviva’s Sampson county, North Carolina, forest biomass facility. Most U.S.-made wood pellets are shipped to Europe where they’re burned to make energy. Image courtesy of the Dogwood Alliance.

However, critics are concerned that the EU’s emissions reduction goals will fall short by a large margin as a result of one neglected aspect of the EU Green Deal that drew little major media coverage: The EU’s Renewable Energy Directive (REDII), as proposed in July, will continue to recognize the burning of wood pellets to make energy as a zero-emissions renewable energy source and a climate-friendly alternative to coal. REDII will also continue the much-disputed practice of not counting carbon emissions released to the atmosphere as Europe burns more than 30 million metric tons of pellets annually.

Notably, the EU is already burning far less fossil fuels to make energy than in the past. But amid an increasingly perilous climate crisis, nothing less than a real reduction in emissions has any chance of slowing global warming, say those who have studied the EU’s wood pellet use and found it troubling.

If the EU is now seen by other nations as a COP26 trendsetter, then its classification of woody biomass as a carbon-neutral way of making energy could influence the policies of other countries, including Japan, the U.K., U.S. and South Korea, causing them to follow suit with potentially catastrophic results for Earth’s forests and climate in the years ahead.

The U.K.’s Drax power station, which imports wood pellets from the U.S. Southeast and Western Canada to burn to make electricity. Unlike the burning of coal, wood burning is counted as carbon neutral, helping the U.K. and EU meet their emissions reduction targets. Image by DECCgovuk via VisualHunt (CC BY-ND).

Good for forests or bad?

This story focuses on the peer-reviewed science of woody biomass, and seeks to determine in part whether the EU’s 55% emissions reduction goal is real or illusory. The biomass controversy can perhaps best be framed by the uncompromising positions of two parties at opposite ends of the biomass spectrum.

“When the EU claims to reduce fossil fuel use and emissions, but burns more forest wood, emissions and forest degradation increase,” said Mary Booth, a U.S. forest ecologist and top expert on biomass usage and policy. “It is tragic that the European Commission did not take the opportunity for meaningful reform of its biomass policies … Refusal to acknowledge the science on biomass is virtually indistinguishable from climate change denial.”

Will Gardiner, CEO of U.K.-based Drax, the world’s largest consumer of wood pellets for energy, could not disagree more. His company burned 7.3 million metric tons of wood pellets in 2020, and he says the science of biomass is on his side. Gardiner contends that harvesting trees for pellet production is good for forests.

“I have a very, very clear view of this,” he told Mongabay at the U.N. COP25 climate summit in 2019. “It is absolutely better to use biomass than coal. The wood pellets we use come from forest ecosystems that are regrown. Fundamentally, we are part of a system that is helping forests to grow and prosper. A mature forest ends up bouncing off, and doesn’t capture more carbon. A managed forest that keeps growing continues to capture more carbon,” he said.

Gardiner’s view is essential to the booming forest biomass industry, which positions itself as a vital part of the solution to the climate change crisis. His claims are also meant to counter forest advocates like Booth, scientists who decry the outsize negative impacts they say wood pellet production and burning is having on global forests, biodiversity, the climate and efforts to curb carbon emissions.

Forest advocates say that cutting down trees and burning them to make energy is bad policy, shouldn’t be subsidized by government, nor be aided by forest industry-friendly regulations. They also say that burning wood pellets is dirtier per unit of electricity produced than burning coal, and that natural forests are best left standing to sequester carbon and harbor the wildlife needed to keep those ecosystems thriving.

The industry argues the opposite, maintaining that burning wood is better for the environment than burning coal for energy and heat, and that logging natural forests is good for the climate because newly planted trees sequester more carbon than mature trees. They also continue saying that forest biomass is sustainable and carbon neutral.

Both viewpoints are supported by dozens of peer-reviewed scientific papers and reports, with the findings evaluated in this story. Links to the research can help Mongabay readers make more expansive comparisons.

The forestry industry position is that the burning of wood pellets is cleaner than coal, carbon neutral, and a means for sustainably managing forests. Image by #ODF via VisualHunt.
A juvenile northern goshawk in Estonia’s Kurgjia forest, an area rich in biodiversity before clear-cutting for wood pellet production. The position of environmentalists is that burning wood pellets to make energy is destructive to biodiversity, dirtier than burning coal, and threatens climate stability. Image by Karl Adami.

Forest biomass: A booming industry

It’s important to note that Gardiner’s arguments on behalf of the biomass industry remain persuasive among European and U.K. policymakers, as well as with some politicians in the U.S. and around the globe. The reasons range from economic to environmental to political.

The industrial-scale wood pellet industry, virtually nonexistent 15 years ago, now generates tens of billions of dollars annually for several large corporations. These few firms are major taxpayers in the poor rural communities where their $100 million pellet plants are typically located, creating a modest number of jobs.

A primary reason for rocketing growth: U.N. and EU policies classifying woody biomass as a “carbon-neutral” renewable energy source has encouraged countries to convert coal-fired power plants to burn biomass, requiring them to spend less on new wind and solar installations in order to meet their emissions-reduction mandates.

Economics and politics aside, the climate benefits of burning wood pellets instead of coal have been challenged since 2009, when Science published a study titled “Fixing a critical climate accounting error.”

Researchers concluded then that “The accounting now used for assessing compliance with carbon limits in the [1997] Kyoto Protocol and in climate legislation [put in place since then] contains a far-reaching but fixable flaw that will severely undermine greenhouse gas reduction goals [if that error isn’t repaired]. It does not count CO2 emitted from tailpipes and smokestacks when bioenergy is being used.”

The study, rather than altering forest biomass policy, ignited an ongoing global dispute.

Depending on point of view, this map showing demand and supply of industrial wood pellets could be seen as good news or bad news for the planet and its climate. In 2017, global demand for industrial wood pellets exceeded 14 million metric tons. By 2027, demand is expected to more than double to more than 36 million tons. The biggest increases in biomass burning by 2027 are expected in Europe, Japan and South Korea, with newly targeted source forests in Brazil, Mozambique and Australia. Image courtesy of the Environmental Paper Network.

A debate vital to the future of the EU and Earth

Whatever one’s position, the biomass industry impetus to supply this “clean energy” is gaining global momentum as it receives multimillion-dollar government subsidies and amasses regulatory support, with that trajectory upward not likely to shift any time soon.

Relentless pressure from global forest advocates to at least stop pelletizing whole trees in the U.S. Southeast, Western Canada and Eastern Europe — which currently account for half of the millions of tons of pellets produced annually and burned in the EU — yielded only minor changes to REDII, none of which will result in lower emissions from biomass.

At present, 60% of the EU’s renewable energy mix comes from burning wood pellets, up from 40% in 2014. The EU is the world’s largest wood pellet market, consuming nearly 31 million metric tons in 2020, up 7% over 2018’s 29 million metric tons.

Increased usage from elsewhere around the globe is also expected, especially as Japan and South Korea plan a shift from coal burning to woody biomass.

“The EU is making a political decision when it comes to [forest] biomass,” said Booth, who has been lobbying EU leaders for years to change their biomass policies. “They are not paying attention to the science.”

In February 2021, more than 500 scientists and economists backed this anti-biomass burning point of view in a scientific appeal to EU leaders.

A forest in Kurgjia, Estonia, prior to clear-cutting for an Estonian wood pellet producer. Image by Karl Adami.
A section of the Kurgjia forest after clear-cutting, as documented by environmentalists commissioned by Greenpeace Netherlands. Image by Karl Adami.

Pro-biomass view: Logging good for forests and climate

The pro-biomass side has pointed to research of its own. They, too, wrote to the EU leaders in February, urging them to develop bioenergy policies “based on sound and relevant science.” In support of their view, they attached a 2014 study published in the Journal of Forestry that reviewed more than 135 peer-reviewed scientific articles exploring “forest bioenergy and carbon debts” and favoring the growing use of biomass.

The study’s key finding: “As long as land remains in forest, long-term carbon mitigation benefits are derived from sustainably managed forests that provide an ongoing output of wood and other biomass to produce long-lived products [like timber] and bioenergy, displacing GHG [greenhouse gas]-intensive alternatives [like coal].”

For biomass advocates, a lot hangs on the word “sustainably.” It conjures positive images of loggers carefully entering forests and precisely harvesting only select trees, while leaving most of the forest canopy intact, or only removing wood waste to be pelletized.

However, investigations by environmental NGOs, including the Dogwood Alliance, Biofuelwatch and Fern, paint a different picture, documenting large clear-cuts of natural and old-growth forests, with thousands of whole trees, known as “roundwood,” piled at pelletizing plants.

The question remains: Does a sustainably managed forest, presumably replanted as trees are cut, provide wood pellets for bioenergy while not reducing, or possibly even increasing, a forest’s capacity to sequester carbon?

A 2018 study by IEA Bioenergy, an energy policy advisory organization to the EU, says the answer is yes: “Carbon losses [through harvest] in some stands are balanced by carbon gains [growth] in other stands, so that across the whole forest landscape, the fluctuations in carbon stock even out.”

The study also notes: “Unharvested forests have declining carbon uptake over time because growth rates diminish as forests get older and approach maturity, or high tree density constrains further growth.”

The U.K.’s Drax power station is a former coal-burning plant converted to become one of the world’s largest industrial users of woody biomass for energy production. Image by DECCgovuk via VisualHunt (CC BY-ND).

Anti-biomass view: Burning trees a climate disaster

A 2014 study published in Nature, titled “Rate of tree carbon accumulation increases continuously with tree size,” is one of many that takes clear aim at the forest industry’s old trees vs. young trees carbon sequestration argument, and denies its veracity. The study analyzed 403 tropical and temperate tree species, with authors reaching this conclusion:

“Large, old trees do not act simply as senescent [aging] carbon reservoirs, but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree … Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to understand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.”

The position taken by the biomass industry that “sustainable” logging does not harm a forest’s carbon-capturing capacity — and even improves it — offers support to the most contentious aspect of the U.N.’s and EU’s policies regarding biomass: that forest biomass is a renewable energy resource on par with zero-emission wind and solar.

Their reasoning? Newly planted trees and forest growth immediately offset the carbon emissions produced by burning millions of tons of wood pellets annually. Thus, countries burning wood pellets — made up of whole trees, lumber waste and forest residue — are not required to report emissions at the smokestack like they are when burning coal. But those emissions into the atmosphere exist regardless.

A top EU official recently went so far as to declare that this carbon accounting loophole is critical to EU nations meeting their emissions reduction pledges under the Paris Agreement — at least on paper. However, science shows that what happens in the atmosphere is quite different.

In the U.S. Southeast, the world’s largest producer of wood pellets, natural forests are often cleared and then replanted with pine plantations. Environmentalists say fast-growing pine does not sequester nearly as much carbon as the hardwood and softwood forests they replace, nor harbor much biodiversity. Biomass backers say fast-growing young forests sequester more carbon than mature forests. Pine plantations like this one are harvested on 20-year cycles. Image by nationalagroforestrycenter via Visualhunt.

Carbon balance arguments

A 2020 study titled “Paper Tiger: Why the EU’s RED II biomass sustainability criteria fail forests and the climate,” addresses sustainable logging claims with the following example.

A 100,000-hectare natural forest, the paper postulates, is capable of sequestering 400,000 tons of CO2 from the atmosphere into new growth annually. The industry would therefore argue that it could harvest 400,000 tons of trees from part of the forest “sustainably” as long as other parts of the forest keep growing and sequestering carbon to maintain the carbon balance.

This, says the 2020 study, is wishful thinking. Annual forest regrowth may absorb a small portion of the stored carbon lost due to 400,000 tons of biomass burned, but that 100,000-hectare forest, no matter how well managed, is incapable of absorbing all of those emissions quickly; it could in fact take many decades to do so — time the world doesn’t have to curb carbon emissions.

According to “Paper Tiger,” harvested trees, turned into pellets and burned, are immediately registered by the atmosphere as an increase in CO2 concentrations, and add to the destabilization of Earth’s climate. The study adds:

“Even though the harvesting was ‘sustainable,’ the biomass is not ‘zero emissions’ or ‘carbon neutral.’ A symptom of this error is that estimates of landscape carbon balance are extremely susceptible to the size of the area assessed. Biomass producers [to get desired research results] need to define large sourcing areas, even if they only actually harvest a small proportion, as this allows them to claim carbon sequestration over the entire area as offsetting carbon loss in the logged area.”

Still, the biomass industry offers another argument touting its product as a vital climate solution: a 2021 study, published in GCB-Bioenergy, concluded that even though forest biomass “carbon neutrality should not be assumed by default,” the value of biomass as a transitional fuel to get us safely to a post-carbon world is worthwhile over coming decades:

“Biomass-based electricity can provide balancing power needed to maintain power stability and quality as the contribution from solar and wind power increases, complementing other balancing options such as battery storage, reservoir hydropower, grid extensions and demand-side management.”

Forest advocates from the Netherlands stage a protest against the use of biomass for energy outside the European Union Parliament in Brussels, where delegates debated revisions to the EU’s Renewable Energy Directive. Dutch NGOs released a study July 7, 2021, concluding that “Research shows that wood production for biomass, which is used in the Netherlands for energy generation in coal-fired power stations, causes serious damage to forests and nature in Estonia.” Image courtesy of Maarten Visschers.

The coal vs. wood pellets conundrum

There is one area in which these adversaries find agreement: biomass proponents and forest advocates concur that burning more wood pellets has led to a dramatic decline in coal usage across the EU and U.K. In fact, 19 of 27 EU nations and the U.K. are on track to phase out coal by 2030.

However, while the biomass industry proclaims this fossil-fuel decline as an unmitigated win for the climate, a host of studies conclude otherwise: Because wood pellets are less energy-dense than coal, pellets actually produce more carbon pollution per unit burned than coal does to generate the same amount of electricity.

“Because combustion and processing efficiencies for wood are less than coal, the immediate impact of substituting wood for coal is an increase in atmospheric CO2 relative to coal,” says to a 2018 study presented in Environmental Research Letters. “The payback time for this carbon debt ranges from 44-104 years after clear cut, depending on forest type — assuming the land remains forest. Surprisingly, replanting hardwood forests with fast-growing pine plantations [a common practice in the U.S. Southeast] raises the CO2 impact of wood because the equilibrium carbon density of plantations is lower than natural forests.”

Implied in this study is something else on which the two sides agree: Assuming that forests cleared for wood pellets really are replanted with similar tree species, burning those wood pellets really is carbon neutral. But critically, the biomass industry tends to talk past the 44-104 years required to achieve carbon neutrality.

The U.N. Intergovernmental Panel on Climate Change (IPCC) made clear in 2018 that the planet has little time to drastically reduce all emissions to avoid even more catastrophic climate impacts than we’re seeing so far this year. The IPCC authors wrote:

“The report finds that limiting global warming to 1.5°C (over a 1900 baseline) would require ‘rapid and far-reaching’ transitions in land, energy, industry, buildings, transport, and cities. Global net human-caused emissions of carbon dioxide would need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050.”

The EU Green Deal, along with REDII, aren’t expected to become law before a year of negotiations among member nations takes place. Forest advocates contend they will keep lobbying for amendments to reduce the bloc’s reliance on biomass and for greater forest protections. Meanwhile, the biomass industry, together with wood-producing nations such as Finland, Sweden and Estonia, are already pushing to protect the status quo.

While the EU generates just 8% of global emissions (third behind China and the U.S.), it carries great influence on the world stage. Final implementation of its Green Deal will determine the effectiveness of the EU’s future emissions reduction pledges and its real-world mitigation achievements or shortfalls. The outcome — and who else follows the EU’s lead — is partly dependent on whose science the majority of global policymakers believe as they negotiate at COP26 in Scotland this November.

Justin Catanoso, a regular Mongabay contributor, is a professor of journalism at Wake Forest University in North Carolina. Follow him on Twitter @jcatanoso.


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Banner image: When wood pellets burn, they release carbon dioxide to the atmosphere, immediately adding to global warming. However, when that CO2 is released from EU smokestacks it is currently counted as producing zero carbon emissions. Image by Michael Frierson.

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