Expanded Use of Modern Wood Heating and Improving Air Quality

Increasingly, modern wood heating is recognized as an effective strategy for reducing fossil fuel use, while stimulating local economies and creating markets for low-grade wood. Yet, there remains apprehension from state policy and rule makers.
By Adam Sherman | March 16, 2017

Over the past few years, a number of states in the northeast U.S. have launched new programs that incentivize the market to switch from oil and propane heating to modern wood heating systems. Increasingly, modern wood heating is recognized as an effective strategy for measurably reducing the use of fossil fuels, while stimulating local economies and creating local markets for low-grade wood. Yet, there remains serious apprehension from state policy and rule makers about increasing wood heating due to concerns about air quality—specifically, particulate matter (PM) emissions. Fear of worsening air quality is a real barrier to expanding the region’s modern wood heating market.

But does increasing the use of wood fuels mean our air quality will get worse? To the contrary, we can use more wood and actually improve air quality.

Over the past two decades, the State of Upper Austria has nearly doubled its use of wood to cut carbon emissions and reduce its dependence on imported fossil fuels. Today, Upper Austria meets over 40 percent of its heating needs with pellets, chips and cordwood. Yet, during that same time, ambient levels of PM were considerably reduced. How? Well, in addition to offering programs aimed at switching from oil to pellets, they offered programs to replace old, inefficient woodstoves and boilers that are a major source of air pollution. By linking equipment replacement programs with fuel-switching programs, use of wood heating and reduction of PM emissions were able to expand at the same time.

How could this be applied in the U.S.? Simple. Based on EPA emissions data, a typical switch of a residential oil boiler to a wood pellet boiler results in a net increase of just 1 pound of annual PM emissions. By comparison, the typical upgrade from an old, non-EPA certified woodstove to a new certified woodstove will yield a net decrease of nearly 200 pounds of annual PM emissions. In other words, for every 200 homes that switched from oil to pellet boilers, a single woodstove change out would completely offset the increased PM emissions. But that 200 to 1 ratio does not help improve air quality. So, what if the ratio was lowered to 100 to 1? In essence, this ratio would produce a 50 percent reduction in PM emissions.

Of course this is an oversimplification, but it does illustrate the opportunity for coordination of state programs for fuel switching and woodstove change outs. As modern wood heating programs are expanded in an effort to make clear and measurable progress toward reducing dependence on imported fossil fuels, lowering carbon emissions, sustaining working forests and stimulating local economies, it is essential that it be done in a thoughtful way that delivers maximum benefits including cleaner air quality. Integrating fuel-switching programs with woodstove change out programs and regulating the ratio of boiler fuel switches to woodstove change outs can yield net air quality benefits over time—an essential element to securing long-term public and political support.  Perhaps we can have our cake and eat it, too.


Author: Adam Sherman
Manager, Biomass Energy Resource Center
802-658-6060
asherman@biomasscenter.org