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The explosion of wood-burning biomass facilities across the country, from large biomass electricity plants to small institutional facilities providing heat in schools and other institutions, is driven by the perception that biomass is "clean," "carbon neutral" and "renewable." In Pennsylvania, the state has allocated millions of dollars in energy grants and loans to biomass energy and fuel pellet manufacturing facilities in recent years.
The science, though, as outlined in our report "Biomass Energy in Pennsylvania" (supported with funding from The Heinz Endowments), says something very different.
Far from being "carbon neutral," wood-burning biomass actually emits more carbon dioxide (the primary global warming greenhouse gas) per unit of energy produced than either gas or coal. Yes, trees can grow back and reabsorb that carbon, but that growth takes many years. The most recent studies show that it takes at least 40 to 50 years for re-growing forests to pay back the "carbon debt" created when trees are cut and burned for electricity.
The renewability of wood is also questionable, as forests would be threatened by any meaningful increase in electricity generation using biomass as fuel. Replacing just 10 percent of the coal used in Pennsylvania would require more than 12.8 million green tons of wood per year -- far more than the state's annual commercial wood harvest (about 5 million tons).
The hype around biomass energy also diverges from reality when it comes to air pollution. Burning wood produces the same pollution that burning anything else does -- including particulate matter, nitrogen oxides, volatile organic compounds and carbon monoxide.
Utility-scale biomass electricity plants that employ modern emissions controls still emit tens to hundreds of tons of these pollutants per year. However, many institutional burners are too small to be covered by federal regulations and employ only minimal emissions controls, making their pollution impact disproportionate.
Our report found that as permitted in Pennsylvania, a school-sized biomass burner is allowed to emit more than seven times the particulate matter of an oil burner, and total allowable particulate emissions are similar to having more than 10 wood stoves venting out the facility's smokestack.
Pennsylvania already has a growing problem with childhood asthma that increased pollution emissions around schools could worsen.
While it is within the state's power to require more effective technologies that would significantly reduce air pollution, it has not done so, even while promoting installation of biomass burners in schools, commercial facilities and other institutions with millions of dollars in grants and loans. Nor does the state require air quality modeling to assess the effects of wood-burners before they are built or local air quality monitoring after one is installed.
Biomass is widely promoted as an affordable and renewable alternative to fossil fuels, but its proponents have been slow to acknowledge that it may impose costs on health and the environment. Employing a three-fold strategy -- more effective emissions controls, preemptive pollution modeling and ongoing air quality monitoring -- is the best way to ensure that increased efforts to provide renewable energy do not worsen air quality in Pennsylvania.
First Published December 26, 2012 12:00 am