You can’t shake a stick in New England these days without hitting someone in the energy field who wants to talk biomass. But what exactly is biomass? And is it a green source of energy?
Generally speaking, biomass means plants. In the context of renewable energy, biomass means plants that are used as fuel. Though this might include corn or grasses in other parts of the country, here in New Hampshire and Vermont biomass means wood: cordwood for the stove, pellets for the furnace, or chips for the power plant.
As the United States reconsiders its fossil fuel use, biomass is a possible renewable energy source for the twin states. Historically, over the millennia, wood has kept humans warm here, and we have lots of experience in the modern era burning it for heat and electricity. There are enough trees here, and they grow well enough that there’s no need to replant after cutting. Wood can be stored and burned only as needed, an advantage over wind and solar. And wood grown here keeps energy dollars in the local economy.
Although the Northeast already uses lots of biomass compared with other parts of the country, as a fuel resource it accounts for only 4 percent of our region’s total energy production. The rest comes from fossil fuel. According to the Biomass Thermal Energy Council in Washington, DC, this could change: up to 25 percent of our regional heating needs could be met by biomass. (An internet search for “Heating the Northeast with Renewable Energy” will produce the complete report.)
Most of this biomass would come from former agricultural lands that would be planted with fast-growing trees, primarily in New York and Vermont. The remainder would come from existing forests, primarily in Maine and New Hampshire. (The report defines the Northeast as the New England states plus New York.) In total, roughly 13 percent of our forests’ annual growth would need to be burned as biomass to meet this goal.
But some fear that a vigorous market for biomass could once again lead to overharvesting, as occurred here in the 18th and 19th centuries, with a loss not just of wildlife habitat and recreational space but also of the potential for lumber and other forest products. An expanded market for biomass is especially troubling to some given another recent statistic: for the first time since the Civil War, we in the Northeast have started converting more of our forests to other uses—primarily roads, housing and other forms of development—than are naturally re-growing on old farmland.
Another knock on biomass is that burning wood isn’t necessarily clean. Almost everyone can think of a smoldering outdoor boiler polluting the neighborhood with possible carcinogens. A third problem is that wood is not a particularly concentrated fuel source. Nearly half the weight of a green chunk of firewood is either water or the cellulose that will be required to burn off that water. You don’t have to move wood far down the road before the fossil fuel savings start to be lost in clouds of diesel exhaust.
Biomass advocates recognize these concerns and believe they can be addressed through good forest management, the proper siting of new power plants, and clean-burning, gasification technology. There are already a half dozen, large-scale, biomass electricity plants in the twin states, the largest being the McNeil facility in Burlington, VT, and the Schiller facility in Portsmouth, NH, both of which can produce 50 megawatts. As for the issue of sustainability, a recent feasibility study conducted by the Biomass Energy Resource Center indicates that an estimated 3.5 million green tons of wood are consumed annually by pulp mills, biomass power plants, seasonal chip-heating systems, and wood-heated homes in Vermont and nearby counties in New York, Massachusetts and New Hampshire. By comparison, the timberland in the same study area regenerates about 25 million tons of net growth each year.
Even more efficient than large power plants would be to burn biomass in relatively small facilities, sited close to their sustainably managed ‘wood sheds,’ providing both heat and electricity through a process called cogeneration. Such plants would generate electricity for a town, village, or school campus while heating nearby buildings and houses with the leftover steam. Dartmouth College, Middlebury College, and the University of New Hampshire are three of more than 100 schools in the U.S. already using energy from cogeneration—though none burns exclusively wood. (Dartmouth could burn wood but is presently burning oil, and Middlebury burns 20 percent wood.) Two dozen secondary schools in Vermont already burn biomass for heat, though not for electricity.
So that’s the state of the debate. Biomass has great potential, but it’s not without pitfalls. Much rides on the outcome, and that’s because while the details of biomass are being sorted out, there’s another statistic to bear in mind. The seven states of the Northeast burn 5 billion gallons of home heating oil each winter, making our region, per capita, one of the largest consumers of home heating oil on the face of the planet.