As an Adjunct professor teaching two unique interdisciplinary courses on sustainable energy at The George Washington University, I read the article that biomass power plants are more polluting than coal with incredulity. Not only is the report incorrectly covered on it's major three points, but it leaves out three other important points that readers need to know. And a recent modeling study on biofuels carbon balance is also lost in the weeds.
In John Upton’s Grist article, he reports “more than 70 wood-burning plants are under construction or have been built in the U.S. since 2005, with 75 more planned, according to the analysis by the nonprofit Partnership for Public Integrity…For every megawatt-hour of electricity produced, even the “cleanest” of the American biomass plants pump out nearly 50 percent more carbon dioxide than coal-burning plants…”
And then Climate Wire reported on a recent University of Nebraska study: "Last week, University of Nebraska, Lincoln, researchers published a paper in Nature Climate Change finding that fuels made from corn residue — the tough, fibrous stalks, corncobs and leaves left atop fields after harvest — could remove carbon from the soil, leading to a net increase of greenhouse gas emissions compared with conventional gasoline over a five-year cycle."
One of the largest U.S. corn stover biofuels producers, POET-DSM, is asking farmers to harvest only 1 ton of corn residue per acre — about 25 percent of the available material — according to the company's website. According to Karlen's calculations of the figures in the Nature Climate Change study, the researchers assume a 75 percent collection rate. Ya know, if you model three times what the actual rate is, sure the carbon balance will be off. But stover is great fertilizer and way less expensive than fossil-based fertilizers, so no way farmers will sell all their stover and replace it with higher cost fertilizers. And that's the point with computer models, unless you interface with the "actors in the field" you will wind up with manure and not good science.
And now, the PPI study not only is wrong on all it’s major points, it’s not even looking at the other emissions of coal-produced electricity and confuses biomass generation with garbage incineration. The sophmoric study would get an “F” in my class. Here’s why:
First and foremost they lump every kind of biomass power generation together and then they confuse mixed waste as biomass in the study. Landfill gas and biogas from manures, sewage, and municipal water systems were left out – and they are the most environmentally beneficial renewable energy generation plants offsetting methane, a potent greenhouse gas and preserving water quality. If you take out municipal solid waste, then of the eight biomass waste streams, they were focusing on only wood.
Supposed Fact One: “For every megawatt-hour of electricity produced, even the “cleanest” of the American biomass plants pump out nearly 50 percent more carbon dioxide than coal-burning plants, PFPI staff researcher Mary Booth, a former Environmental Working Group scientist, concluded after poring over data associated with 88 air emissions permits. The biomass plants also produce more than twice as much nitrogen oxide, soot, carbon monoxide, and volatile organic matter as coal plants.”
Comparing Uncontrolled Emissions from Different Fuel Sources
Supposed Fact Two: “The problem is rooted in lax regulations for an industry that’s widely mistaken to be clean. EPA rules allow biomass-burning plants to produce more than twice as much pollution as coal plants. Because of this perfect storm of lax regulation and regulatory rollbacks, biomass power plants marketed as 'clean' to host communities are increasingly likely to emit toxic compounds like dioxins; heavy metals including lead, arsenic, and mercury; and even emerging contaminants, like phthalates, which are found in the 'waste-derived' fuel products that are being approved under new EPA rules. …”
According to biomass expert Bill Carlson: “Perhaps one third of the total PPI document is devoted to Hazardous Air Pollutants (HAP) emissions from biomass and the lack of regulation, control and documentation. In reality, if lead or mercury or chlorine is not present in fuel in the first place, it is not going to be present in emissions. EPA and state regulators appreciate and accept this fact, but the authors clearly do not understand it. Much is made of dioxin and HCL in the report, but virgin wood does not contain more than trace amounts of chlorine, a necessary element in in both pollutants. The vast majority of biomass fuel in the United States remains residue and waste material from the agriculture and forest products industries, and that is not expected to change. These materials do not contain the precursors for the HAPs of greatest concern. And, if the wood fuel contains no mercury to begin with, it is not going to be formed in the combustion process.”
The paper states that biomass power seeks to avoid more stringent EPA emission limits and instead finds a way to rely on more lenient state standards. In fact, the relationship was designed such that the EPA limits are a minimum, and can be exceeded by the states, but never made less stringent. The Clean Air Act was designed so that states could get “delegated authority” from EPA to run the air quality permitting program so long as they ran it in accordance with an EPA approved State Implementation Plan — a system that has been in place for more than 40 years and works just fine.