This commentary is by Darren Springer, general manager of the Burlington Electric Department, and Betsy Lesnikoski, chief forester for the McNeil Generating Station.
As Vermont seeks to make continued progress toward reducing greenhouse gas emissions and supporting local renewable energy projects, questions have been asked about how biomass energy fits as part of our climate strategy.
At Burlington Electric Department, we have proudly operated the biomass-fueled McNeil Generating Station for over 35 years, on behalf of McNeil’s joint owners (Burlington Electric owns 50 percent, Green Mountain Power owns 31 percent and Vermont Public Power Supply Authority owns 19 percent). McNeil is one of Vermont’s original local renewable energy projects, built in the early 1980s to replace coal generation at Burlington’s Moran Plant.
McNeil is a 50-megawatt electric generating plant and is the largest energy producer in Vermont following the 2013 closure of the Vermont Yankee nuclear plant.
McNeil is relatively unique for having four professional licensed foresters on staff who work to ensure a sustainably managed wood supply. McNeil harvesting standards require our wood to come from managed sites that have plans to promote forest growth and protect wildlife and water quality. In fact, sites we sustainably harvested decades ago have been revisited when harvesting is called for in their forest management plan.
Most of McNeil’s wood supply comes from forest residues, which is wood left over from traditional logging operations for higher-value products. By purchasing low-value residues that otherwise lack a market, McNeil provides a critical economic value for forest lands and supports jobs for Vermonters who work and steward those lands. McNeil also uses sawmill byproducts and urban waste wood collected at our popular Waste Wood Yard as fuel for the plant.
Analysis conducted by a third-party firm, Innovative Natural Resource Solutions, included in Burlington Electric’s integrated resource plan, estimated that total economic benefits from McNeil in Vermont exceed $49 million annually. This includes supporting 80 jobs at the plant and in the wood supply chain, and purchases of $4 million of wood in 2019 across eight Vermont counties — Addison, Chittenden, Franklin, Lamoille, Orleans, Rutland, Washington and Windsor.
While the economic impact of McNeil is significant, the plant’s environmental profile is also important to understand. McNeil’s joint owners have invested in emissions reduction equipment, including a $12 million regenerative selective catalytic reduction system in 2008 that helped reduce nitrogen oxide emissions to levels well below those allowed under state regulations. McNeil’s particulate stack emissions are seven times lower than the level allowed under Vermont state regulations, and 11 times lower than the federal level.
Our understanding of climate change and the biomass carbon cycle has increased since McNeil was built. The U.S. Environmental Protection Agency currently treats emissions “resulting from the combustion of biomass from managed forests at stationary sources for energy production as carbon-neutral.” The Intergovernmental Panel on Climate Change reported that “in the long term, a sustainable forest management strategy aimed at maintaining or increasing forest carbon stocks, while producing an annual sustained yield of timber, fiber or energy from the forest, will generate the largest sustained mitigation benefit.” The Innovative Natural Resource Solutions report states that “carbon contained in wood fuel is already part of the above-ground carbon cycle, unlike fossil fuels which take ancient carbon that has been sequestered for millions of years and adds it to the atmosphere.”
When it comes to McNeil, the Innovative report found that timberlands providing McNeil’s wood supply in Vermont and New York have been increasing their contribution to carbon sequestration even as they provide sustainable harvests for McNeil. All harvesting activities in Vermont remove approximately 50 percent of the annual new growth, with 50 percent of the new growth remaining unharvested and adding to above-ground carbon storage in our forests. McNeil wood supply is estimated to account for just 4 to 5 percent of annual net new forest growth in Vermont.
The most recent data from the Vermont Agency of Natural Resources shows that in 2016 Vermont had total greenhouse gas emissions of 9.76 million metric tons, excluding biomass energy and forest sequestration. The two largest sources of emissions are fossil fuels — transportation gasoline, and fuel oil and propane use in buildings. However, Vermont’s forests provide carbon sinks that sequester carbon and reduce our net state emissions.
Biomass energy plays an important economic role in keeping forests intact by providing a market for low-value residues, protecting forests from development that would reduce their carbon sequestration. When including emissions from biomass energy and net sequestration benefits (all carbon sinks and sources) from our forests, total state emissions drop to approximately 6 million metric tons.
In other words, even accounting for biomass energy, the sustainable management of forest lands in Vermont is providing a significant net emissions benefit. The Agency of Natural Resources report indicates that biomass from residues (which McNeil uses) is preferable to non-residue wood and that biomass is preferable to fossil fuels from a carbon standpoint.
Having said all this, just as Vermonters look at opportunities to improve efficiency in our homes, we continually look for ways to improve efficiency at McNeil, including potentially adding a district energy system that could capture waste heat and additional steam from McNeil to displace thermal fossil fuel use in Burlington. The current district energy proposal under consideration would improve efficiency at McNeil and reduce commercial-sector thermal greenhouse gas emissions in Burlington by more than 11.5 percent, the single biggest emissions-reduction opportunity in that sector in Burlington. McNeil is also set to host a solar research center and conduct a pilot project to examine opportunities to improve efficiency at the plant with a startup energy company (as part of the DeltaClime Vermont business accelerator program).
As we work to meet critical local and state renewable energy and climate goals, the sustainable use of biomass plays an important role both in providing modern wood heating in buildings, and as demonstrated for over 35 years at McNeil, serving as an important source of electric generation that supports the local economy and sustainable forestry.
