PATRICK-MURRAY ADMINISTRATION RELEASES BIOMASS SUSTAINABILITY STUDY
Report shows that electricity from biomass compares unfavorably with coal, while biomass for heat and cogeneration reduces greenhouse gas emissions over time; Department of Energy Resources to revise regulations for state's Renewable Portfolio Standard based on study
The six-month study of issues associated with biomass sustainability and carbon policy conducted by a team of scientists and policy experts led by the Manomet Center for Conservation Sciences shows that the use of biomass for heating and combined heat and power (CHP) facilities would result in a 25 percent reduction in greenhouse gas emissions in 2050 relative to oil, but biomass-fired electricity would result in a 3 percent increase in emissions over coal-fired electricity in 2050. Coal has the highest greenhouse gas emissions per kilowatt-hour of energy produced of any fossil fuel.
Under the Global Warming Solutions Act, Massachusetts is required to reduce greenhouse gas emissions across the economy 80 percent by 2050.
"These findings have broad implications for clean energy and the environment in Massachusetts and beyond," said Secretary of Energy and Environmental Affairs Ian Bowles. "Biomass energy can be renewable over the long term and it has benefits in independence from imported fossil fuels. But now that we know that electricity from biomass harvested from New England forests is not 'carbon neutral' in a timeframe that makes sense given our legal mandate to cut greenhouse gas emissions, we need to re-evaluate our incentives for biomass."
Biomass technology for generating electricity has qualified for incentives under the Massachusetts Renewable Portfolio Standard (RPS) since the RPS was created in 2002 under the Electricity Restructuring Act of 1997. The RPS provides financial incentives for eligible renewable energy facilities by requiring utility companies and other electricity suppliers to deliver a minimum percentage of RPS-qualified renewable energy to their customers. The Green Communities Act of 2008 accelerated the rate of increase of this percentage (currently 5 percent) from 0.5 to 1 percent annually.
Shortly after the passage of the Global Warming Solutions Act of 2008, an interagency team from the Department of Energy Resources, the Department of Environmental Protection and the Department of Conservation and Recreation began exploring the potential greenhouse gas implications and forest sustainability impacts of biomass incentives. In December 2009, DOER suspended qualification of any new biomass facility for RPS pending the Manomet Center study and development of sustainability criteria addressing biomass supply and greenhouse gas impacts.
"Unlike wind and solar, biomass is a form of renewable energy that emits carbon," said Department of Energy Resources Commissioner Phil Giudice. "With the scientific information provided by the Manomet team, we can begin the process of refining our renewable energy regulations to provide incentives only for biomass energy that truly reduces our greenhouse gas emissions and protects our forests."
As explained in the Manomet Center report, forest biomass generally emits more greenhouse gases per unit of energy produced than fossil fuels. The report terms these excess emissions, biomass's "carbon debt." For biomass electricity, that initial carbon debt is 31 percent compared with electricity from coal. Over time, however, re-growth of the harvested forest removes this carbon from the atmosphere, reducing the carbon debt associated with the initial combustion of biomass for energy. After the point at which the debt is paid off, biomass begins yielding "carbon dividends" in the form of reduced greenhouse gas levels in the atmosphere compared with fossil fuels for producing the same amount of energy.
Biomass Carbon Debt Payoff
Carbon Debt Payoff
Oil (#6), Thermal/CHP
For each year of biomass energy generation, initial carbon debts are incurred, while benefits from forest regrowth (and carbon recapture) also begin to accrue. Comparing 40 years of biomass emissions, beginning today, with 40 years of continued fossil fuel burning, the report shows that replacement of oil-fired heating or CHP capacity with biomass fully offsets the carbon debt and lowers greenhouse gas levels by approximately 25 percent compared with oil. For biomass replacement of coal-fired power plants, however, the net cumulative emissions in 2050 are 3 percent greater than they would have been from using coal to generate electricity, while replacing natural gas in power generation results in even higher cumulative emissions from biomass.
Cumulative Carbon Dividends from Biomass Replacement of Fossil Fuel
Biomass Cumulative % Reduction in Carbon Emissions
(Net of Forest Carbon Sequestration)
Oil (#6) Thermal/CHP
In terms of sustainable biomass supply, the report determines that, at current market prices and renewable energy incentives, biomass energy could increase forest harvesting in Massachusetts by 150,000 to 250,000 green tons per year - not enough to support one 50 MW biomass electric plant, but sufficient to fuel 16 CHP units. Harvested acreage is not expected to increase from current levels, but rather biomass fuel would come from removal of logging residues and poor quality trees at sites harvested for timber. At this level of harvest, the combined volume of timber and biomass harvests represents less than half of the annual net forest growth across the state's private forest lands. Only significantly higher prices for forest biomass, due to sharp increases in fossil fuel prices or renewable energy incentives, could result in additional harvesting approaching the net annual growth of existing forest stock.
In addition, the report acknowledges that harvests for bioenergy facilities could have more significant localized impacts on the landscape, including aesthetic impacts of locally heavy harvesting as well as potential impacts on recreation and tourism. The report suggests four general options the state could use to protect public values at the landscape scale:
- Option 1: Establish a transparent self-monitoring, self-reporting process for bioenergy facilities indicating where the supply came from according to a number of assurance criteria ranging from use of a licensed forester to compliance with Forest Guild biomass harvesting and retention guidelines or certification by Forest Sustainability Council.
- Option 2: Require bioenergy facilities to purchase wood from forests with approved forest management plans.
- Option 3: Require bioenergy facilities to submit wood supply impact assessments.
- Option 4: Establish formal criteria for approval of wood supply impact assessments. Possible approval criteria might be based on limits on the amount of harvests relative to anticipated forest growth in the wood basket zone.
The report also notes that current forest cutting regulations provide considerable protection for water quality and forest regeneration, but recommends additional environmental protections at the biomass harvest site, including new standards that ensure enough coarse woody debris is left on the ground, particularly at nutrient poor sites, to ensure continued soil productivity, as well as sufficient standing dead wildlife trees remain to promote biodiversity.
In addition to the Manomet Center, the team that produced the report includes the Pinchot Institute for Conservation, the Forest Guild, the Biomass Energy Resource Center, and other independent forest ecologists and resource economists. The work of the team was reviewed by an Independent Advisory Panel including David Foster, Director of the Harvard Forest, and Alaric Sample, President of the Pinchot Institute -organizations that are global leaders on carbon neutrality, ecosystem management, environmental policy and the conservation of forest landscapes.
DOER will hold a set of public meetings in July to review the Manomet report and discuss policy implications and options. These discussions will be followed by an open policymaking process in July and August to gain stakeholder input on potential changes to the Renewable Energy Portfolio Standard (RPS) and other policy options. Following this public review, DOER will engage in formal rulemaking to revise the RPS regulations to include standards governing biomass feedstock and greenhouse gas impacts.