As California looks for ways to reduce its carbon footprint and help curb climate change, environmental activists are questioning the integrity of the biomass industry, which burns millions of tons of woody plant matter each year to help power the state’s electric grid.   

Plant matter and wood waste represent a step forward in an age needy of clean and renewable energy sources, according to biomass industry leaders. They insist that burning biomass is a carbon neutral activity, meaning it causes no net growth of the atmospheric carbon load. This, they say, is because trees grow back, sequestering carbon as they do and thereby offsetting the CO2 emissions from biomass power plants.  

But many environmental activists argue that biomass has been credited as carbon neutral through mathematical errors that have influenced renewable energy incentive programs. In February, several dozen scientists signed a letter written to the Environmental Protection Agency in response to the government’s support of biomass energy. The authors warned the agency that it had made serious calculation errors in crediting woody biomass as a carbon-neutral fuel source — errors that are likely to be repeated in other nations unless corrected now. According to the authors, meeting just 4 percent of the nation’s energy needs with biomass would require burning 70 percent of the timber currently harvested in the United States. In other words, this tiny gain in energy supply would require almost doubling the nation’s timber harvest.

Kevin Bundy, a senior attorney at the Center for Biological Diversity, says biomass received the carbon neutral stamp of approval last decade. In 2002, he says, the state introduced a program called the Renewable Portfolio Standard, which requires energy providers to increase reliance on renewable energy resources to one-third of total procurement by 2020. Biomass, Bundy explains, was included as an option in the Renewable Portfolio Standard. Later, in 2006, state legislation was passed calling for reducing greenhouse gas emissions to 1990 levels by 2020 via clean energy development. But that law — Assembly Bill 32, the California Global Warming Solutions Act — used the Renewable Portfolio Standard as a guideline and in doing so made a serious flub, according to Bundy.

“They assumed that any [energy source that is] renewable had a low carbon footprint,” he explains. “Now, because biomass is renewable, it gets lumped in with [wind, sun and water].”

Princeton researcher Tim Searchinger, who signed the February letter to the EPA, says such carbon accounting errors have by now been institutionalized as fact and written into policies worldwide aimed at mitigating climate change. As a result, Searchinger warns, the biomass industry is enjoying subsidies and regulatory exemptions that could drive global deforestation and fuel climate change.

For more on the biomass industry, check out Alastair Bland’s July feature, “Burn Notice.”