Why Scientists are Concerned About Tree-Burning Power Plants (Op-Ed)

Sasha Lyutse is a policy analyst for the NRDC. This Op-Ed was adapted from a post to the NRDC blog Switchboard. Lyutse contributed this article to LiveScience's Expert Voices: Op-Ed & Insights.

Ahead of the Thanksgiving holiday, 41 leading scientists sent a letter to the U.S. Environmental Protection Agency (EPA) calling on the agency to protect U.S. forests from the growing sucking sound created by biomass power plants. The scientists urged the agency to put in place a regulatory system that is both science-based and takes into account the key recommendations of the science panel the agency itself commissioned.

As power plants look for alternatives to fossil fuels, some are turning to burning wood or other plant materials — known as biomass — to generate electricity. The biomass industry argues that because trees grow back, biomass offers a "carbon neutral" form of energy. But not all biomass is created equal.

Trees are not the same as perennial grasses or harvest residues that can either regrow quickly, would otherwise be burned in the field or are not needed for other purposes. And the latest science reveals that burning whole trees for energy results in more carbon emissions than burning coal for decades. That's because trees are less energy-dense than coal, and harvesting them for fuel means foregoing the carbon they would have absorbed from the atmosphere if left standing.

This video animation shows what happens to the balance of carbon between forest and atmosphere when people burn forests to produce energy instead of allowing trees to keep their day jobs — as massive carbon storage facilities.

In 2011, the EPA took on this issue. The agency issued to biomass-burning plants a three-year exemption from permitting requirements under the Clean Air Act (basically a requirement that each new and modified industrial source gets a construction permit before starting to build, showing that it will use the "best available control technology" for each pollutant subject to regulation under the Clean Air Act). The agency then initiated a science-driven process to develop rules for properly quantifying carbon emissions from these plants. It issued a draft methodology for doing the necessary carbon accounting, then empaneled a group of expert scientists — known as the Science Advisory Board (SAB) — to assess the scientific validity of the proposed approach.

Now in the home stretch of developing those rules, the message from the scientific community is clear: Regulations governing how stationary sources account for biogenic carbon emissions must be based on sound science and ensure adequate protections for forests and the climate and the EPA must follow through on the science-driven process for creating those regulations that it put in place more than two years ago.

As their letter states, "Doing otherwise at this juncture will fail the test of rigorous, science-based policymaking and could result in regulations that distort the marketplace towards greater use of unsustainable sources of biomass, with significant risks to our climate, forests and the valuable ecosystem services they provide and we rely on."

The scientists also shared their serious reservations about the accounting methodology that EPA proposed in its draft framework, and underscored three key conclusions of the SAB's final report:

• Bioenergy is not inherently carbon neutral. Instead, it is critical that EPA consider the heterogeneity in biomass feedstock types, sources and bioenergy production methods define carbon outcomes based on "what the atmosphere sees;"
• EPA cannot grant biomass-burning power plants credit for forest growth and carbon sequestration that would be happening anyway. Only when bioenergy results in additional carbon being sequestered above and beyond the anticipated baseline (the "business as usual" trajectory) can there be a justification for concluding that such energy use results in little or no increase in carbon emissions.
• EPA must develop a scientifically-sound methodology for determining the carbon emissions impact to the atmosphere from burning long-recovery biomass feedstocks — most notably, whole trees. This requires comparing forest growth and carbon sequestration on the landscape with biomass sourcing for energy production to what would have happened absent bioenergy.

Power plants account for 40 percent of the U.S. carbon footprint. That makes EPA's effort to reduce carbon pollution from power plants a key part of the climate fighting initiatives of the administration of President Barack Obama, and ensuring that a rigorous accounting for biomass carbon emissions will be critical to the effort's integrity. As the scientists conclude, the only way to encourage bioenergy facilities to source low-carbon biomass resources, efficiently burn or otherwise convert them to electricity, and to use the electricity and heat in the applications that most effectively reduce carbon emissions is for EPA to follow the science.

It's critical that EPA heeds the science community's call and follows through on the standard it set for itself in issuing rules for the bioenergy industry. It can do both by adopting the SAB's key recommendations.

This Op-Ed was adapted from "41 Leading Scientists Call on EPA to Protect Our Forests and Climate" on the NRDC blog Switchboard. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on LiveScience.