Clean air and clean power means being smart in how we choose biomass fuels

Last Monday, President Obama took a truly historic step in the fight against climate change, announcing first-ever limits on carbon pollution from existing power plants in the US. Power plants are responsible for 40% of our carbon pollution, the single largest source. The new emissions standards, known as the Clean Power Plan, could reduce carbon pollution by up to 30% by the end of this decade. This will move the US towards the goal of cutting total emissions of greenhouse gases—the heat-trapping gases responsible for warming our planet—17% below 2005 level by 2020 and help avoid the worst consequences of climate change.

Some of the power plants covered by the new standards burn not just coal, but a mix of coal and wood or other plant materials—known as biomass. Others would burn only biomass fuel. When trees and other plant materials are burned, the carbon they have accumulated over many years is released immediately into the atmosphere, just as with coal. That means that accounting for the carbon that’s emitted when large power plants burn biomass will be a key part of ensuring that these new standards really do help clean up our air and climate. 

In 2011, EPA committed to a science-driven process to determine how to best account for the carbon emissions associated with different biomass fuels. It issued a draft accounting framework, empaneled a Science Advisory Board (SAB) that reviewed that framework, and created a process in which the broader scientific community, the general public, and public interest organizations could weigh in.

In the preamble to the proposed rule outlining the Administration’s Clean Power Plan, the Environmental Protection Agency rightly states that biomass can come in many forms and that the carbon impacts of burning biomass for energy are sensitive to the type of biomass feedstock used. The agency points out that its own SAB concluded that, while in some cases bioenergy can be carbon neutral, “additional considerations are warranted” to fully understand carbon impacts for all circumstances.

While acknowledging that accounting for different feedstocks in different ways is a critical principle, EPA needs to be clearer about how it will make sure it isn’t creating incentives to use the kinds of bioenergy that would make climate pollution worse. Some forms of biomass fuel, such as tops and limbs from forest harvest operations and dedicated energy crops, have the potential to reduce carbon emissions compared to fossil fuels. But others, most notably whole trees, can exacerbate climate change. The best and most recent science shows that chipping up and burning whole trees for electricity increases carbon emissions compared to coal and other fossil fuel for decades. 

Ignoring carbon emissions from biomass therefore risks compromising the very goals the President set forth. It could mean we clamp down on carbon pollution from burning coal, but end up increasing carbon emissions by burning our forests.

Given this need to differentiate across biomass sources and get the carbon accounting right, states will need guidance from EPA on how to account for the carbon emissions from different types of biomass fuel. This is the most important thing EPA can do to help guide the biomass energy industry towards low-carbon biomass fuels that help us achieve our climate goals and away from high-carbon sources of biomass that could exacerbate emissions from our power sector.  

EPA correctly highlights that our forests are one of the best tools we have to fight climate change, sucking carbon out of the atmosphere and storing it safely in trees and soils. As the agency notes, our standing forests serve as a critical carbon “sink”, offsetting more than 12% of our annual, economy-wide greenhouse gas emissions.

From the perspective of the atmosphere, cutting down and burning a carbon sink has the same impact as creating an equivalent-sized smokestack. It also risks disrupting these vital carbon sinks and impedes ongoing forest carbon sequestration. That’s why tackling climate change means curbing smokestack emissions and also maintaining and expanding our forests.

But, in passing, the agency’s power plant proposal makes the nonsensical suggestion that because our forests are sinks “broadly speaking, burning biomass-derived fuels for energy recovery can yield climate benefits as compared to burning conventional fossil fuels.”

How does it follow that because the forests are good for the climate, cutting and burning the forests is good for the climate? That’s like saying that because a business is profitable selling off its assets is a good way to help the economy.

Allowing biomass-burning power plants to take credit for forest growth and carbon sequestration that would be happening anyway or that is already accounted for would be a major carbon accounting error that sets back our efforts to tackle climate change.

EPA set an admirably high, science-driven standard for itself in evaluating the climate impacts of biomass energy. The agency must now hold itself to that standard. 

In its September, 2012 final report, the SAB raised critical concerns about EPA’s proposed biomass carbon accounting framework and offered important solutions. EPA should heed the input of its scientific advisors and dozens of scientists from around the country. These offer the agency a path forward that would ensure we protect our forests and support a biomass energy industry that helps achieve the goals set forth in the President’s Clean Power Plan. It’s time for EPA to take that path.  

About the Authors

Sasha Stashwick

Senior Advocate, Energy & Transportation and Food & Agriculture programs

Join Us