Burning trees for power in the Southeast would increase carbon pollution for decades

A new study examining the climate impacts of using biomass to produce electricity in the Southeast adds to a growing body of science challenging the notion that all biomass is carbon-neutral, concluding that burning trees in the region's power plants would increase carbon emissions for decades.

The study, conducted by the Biomass Energy Resource Center in partnership with the Forest Guild and Spatial Informatics Group, looks at the energy demand of 22 39 existing and proposed biopower facilities in the Southeast and asks how the carbon emissions impacts of meeting that demand by burning biomass would compare to using coal or natural gas.

The conclusion is clear:

“Based on current trends….biomass energy in the Southeast is projected to produce higher levels of atmospheric carbon for 35 to 50 years compared to fossil fuels.”

It is important to note that this is the amount of time it takes for the biopower facilities to pay back their initial carbon “debt” relative to fossil fuels. It is only after this payback period that biopower results in lower atmospheric carbon than fossil fuel alternatives.

A 50-year carbon debt is unacceptable. And this finding is not an outlier. The study’s conclusions are consistent with a comparable analysis in the Northeast conducted by the Manomet Center for Conservation Science, which found that between the release of carbon when trees are burned and the slow re-absorption of carbon out of the atmosphere as new trees re-grow, biopower production would increase emissions compared to coal for 40 years.

Like giant lungs, our forests absorb vast amounts of carbon out of the atmosphere every day. This makes forests one of our best defenses against global warming—one Americans rely on to offset 13% of our annual greenhouse gas emissions.

Unfortunately, energy policies have largely ignored this vital benefit, instead identifying forests as a source of supposedly “renewable” fuel for power production. This is based on the false assumption that all biomass is carbon-neutral—meaning that it eventually re-grows and so completely balances the production and use of carbon, resulting in zero net emissions. As a result, demand for biomass is growing rapidly as power companies come under increased pressure to find alternatives to fossil fuels. [To get the basics on biomass and the risks of burning our forests to produce electricity, check out our fact sheet and video animation.]

So why does this matter?  And why does it matter right now?

It’s critical that we transition quickly from burning dirty fossil fuels like coal to clean, renewable energy resources like wind, solar, and low-carbon sources of biomass that can scale up sustainably and deliver real carbon savings soon. Near-term reductions in carbon emissions are needed to stabilize atmospheric GHG concentrations at 450 parts per million (in carbon dioxide equivalent units) and limit expected global warming to 2 degrees Celsius. Beyond that, we risk crossing so-called “tipping points”, at which point scientists increasingly believe that dangerous impacts may become inevitable. This means we simply cannot afford to wait multiple decades for biopower systems to start delivering carbon benefits.

This new study comes at a time when policies regarding accounting for biomass carbon emissions are front and center. As part of its Clean Air Act permitting of large GHG-emitting facilities, the EPA is developing a framework for accounting for the carbon emitted when large power plants burn biomass. As we discussed here, the expert science panel charged with advising EPA in this process issued a clear and unequivocal rejection of the idea that biomass can automatically be treated as carbon-neutral. It also reinforced the notion that EPA must evaluate the incremental carbon impact of a given biomass-burning facility from the perspective of the atmosphere rather than just giving facilities carbon credit “on spec” for biomass re-growth they claim will happen in the future.

Here, the analytic methods used in both the Southeastern and Manomet studies are instructive. To examine the atmospheric effects of regional biopower generation, both developed a “business-as-usual” baseline and then projected the carbon emissions impact of different scenarios in which electricity was created either from woody biomass or fossil fuels. 

In contrast, instead of evaluating the incremental carbon emissions impact of biomass-burning facilities, EPA’s proposed accounting framework evaluates carbon emissions from bioenergy production against a single reference point baseline set according to regional, land-based carbon stocks. If written into policy, this approach would do little to tell us what would have happened to carbon in the atmosphere or on the land absent bioenergy—and so could not accurately reflect the carbon impact of bioenergy production.

The authors of the Southeastern study speak to this issue directly:

“This is a more dynamic approach than was recommended in EPA’s accounting framework for biogenic sources released in September 2011. Although, EPA acknowledged the “comparative” approach used in this study as a more comprehensive accounting method, it chose a “reference point” approach because of the perceived difficulties and challenges in applying a more dynamic approach to actual situations in the field. This study provides an example of how more dynamic accounting can be accomplished and should be considered by EPA in its carbon accounting deliberations.”

With a rapidly growing bioenergy industry adding substantial new demand for biomass to the existing market for forest products, the pressure on our forests has never been greater—particularly in regions like the Southeast. This new study highlights the dangers of burning whole trees for energy and underscores the importance of sound biomass carbon accounting if we are to address the challenges posed by climate change. It’s critical that these scientific advancements be reflected in bioenergy policies at the state and federal level.

The bottom line is that we need to change course now to avoid locking ourselves and future generations into a dangerously disrupted climate. This means finding every way we can to promote clean, homegrown energy sources that maximize climate benefits. This includes supporting investments in the 21st century biopower plants that help create jobs and protect our air and forests instead of destroying them. But regulations that ignore the carbon released when biomass is burned distort the marketplace towards highly unsustainable sources of biomass like whole trees that will increase carbon emissions for decades. We can’t afford it.