FIREDUPÂŚ
Wood Heat in the Northeast Researchers say using wood for heat is effective as long as it’s harvested sustainably.
In the Northeast, using forest biomass for heat would be far more effective in replacing liquid fossil fuels than converting it to cellulosic ethanol for road transport, and it could replace as much as one-quarter of liquid fossil fuels currently being used for industrial and commercial heating in the region. That was one of many conclusions of a study released in mid-February by the Cary Institute of Ecosystem Studies, which teamed up with the Environmental Defense Fund and University of Vermont’s Gund Institute for Ecological Economics to analyze the supply of wood in the Northeast and the impacts of intensive forest harvest to supply biomass energy. Charles Canham, lead author of the study “Forest Biomass and Bioenergy: Opportunities and Constraints in the Northeastern United States,� points out that it is widely assumed forest biomass is going to be an important part of the Northeast’s renewable energy supply, and there’s little debate that if it’s done sustainably, using wood from its forests can have significant environmental and economic benefits. “There’s been an awful lot of speculation about how much energy our forests can produce, and that’s what the report addresses; it assesses the potential of this form of renewable energy to replace fossil fuel consumption, in the eight Northeastern states,� he says. Forests cover a little more than two-thirds of the Northeast landscape. “That’s a remarkable recovery from 100 years ago when forests had been cleared from much of our landscape, and surprisingly the current forest landscape is very close to optimal in terms of productivity and its ability to sequester carbon,� says Canham, a forest ecologist and senior scientist at Cary Institute. What might come as a surprise is that the existing forest products industry already harvests most of the available net State
Area of Forestland (hectares)
Connecticut Maine Massachusetts New Hampshire New York Pennsylvania Rhode Island Vermont Total
697,829 7,145,731 1,221,938 1,943,857 7,669,011 6,738,913 141,001 1,856,854 27,415,133
growth for traditional wood products. “From our analysis, the bulk of additional biomass available for bioenergy will have to come primarily from waste from logging practices,� Canham says. “The total we can sustainably harvest for bioenergy is a lot lower than what studies have previously said, although I have to note those early studies were typically based on much more limited data than our analysis.� The bottom line is that if all of the additional forest biomass that the researchers believe is sustainably available is channeled into the most efficient forms of biomass energy, it could make up from 1 to 2 percent of the region’s energy consumption, Canham says. That number varies, however, if the biomass is targeted at specific energy sectors. “Then it could represent a much more significant component of energy used,� he says. “For example, we estimate if you use all the additional biomass to make pellets used to make residential heat, you could replace 16 percent of the oil we currently use for heat. If all of it was used to generate electricity, it could represent around 5 percent ON THE WEB of what we currently use.� To access a copy of the report, Canham says those numbers are visit www.caryinstitute.org/ small but significant. “They are smaller report_biomass_2011.pdf than a lot of the hope and expectations out there, but they are still important numbers that would preserve working forests, create local jobs and develop regional renewable energy sources,� he says. “More to the point, they could represent a meaningful fraction of a renewable energy standard that most states have adopted or are considering. But this is where the caution has to come in—the benefits are lost if new regulations and incentives lead to unsustainable harvest rates.� —Anna Austin
Total Live Tree and Sapling Aboveground Biomass (metric tons) 108,731,556 602,552,693 183,057,479 251,365,457 981,655,842 920,560,580 19,944,474 249,572,980 3,317,441,061
Merchantable Biomass (metric tons)
Average Merchantable Biomass (metric tons)
80,489,837 381,242,694 135,522,519 177,544,327 701,468,378 667,356,854 14,520,667 177,665,817 2,335,811,095
115 53 110 91 92 99 103 96 85
Total aboveground tree biomass (adult trees plus saplings), and live tree merchantable biomass (biomass above the stump and below a 10.2 centimeter top branch diameter) in the Northeast, are shown by state and for the region as a whole, and per unit area (hectare).
APRIL 2011 | BIOMASS POWER & THERMAL 17