Analysis shows wood pellet fuel reduces greenhouse gas emissions by more than half over fossil fuels
The Northern Forest Center commissioned an independent third-party study of the greenhouse gas impacts of heating buildings with state-of-the-art wood pellet boilers. The Spatial Informatics Group-Natural Assets Laboratory (SIG-NAL) used data specific to the region’s forest composition and harvest practices, and the pellet sourcing and manufacturing of 9 out of 10 Northern Forest pellet mills, all of which produce pellets exclusively for thermal (heat) generation.
The life-cycle analysis, which accounts for all greenhouse gas emissions from sourcing, processing, and transporting fuels, finds that:
On day one, using wood pellets for heat reduces greenhouse gas emissions by 54% compared to oil and 59% to natural gas.
After 50 years, greenhouse gas emissions from pellets drop to 62% less than oil, 67% less than natural gas, and 56% less than propane.
For more information, take a look at a fact sheet summary.
The analysis by Thomas Buchholz, PhD. and John Gunn, PhD., Spatial Informatics Group-Natural Assets Labratory (SIG-NAL), has been peer reviewed and published in the journal Energy.
Net Emissions Comparison
Almost half of pellet content recaptured from other uses
In 2015, the average Northern Forest- produced wood pellet was comprised of:
- 44% sawdust and other byproducts of forest product manufacturing—wood that was cut for other purposes;
- 56% low-quality pulpwood and small trees, usually the byproduct of harvesting for higher value timber;
- Less than 1% from other sources, such as landscaping and municipalities.
About the Study
SIG-NAL analyzed the greenhouse gas impacts of using modern wood heat in the Northern Forest using a forest sector life-cycle assessment tool and data not previously available.
- The mix of energy sources used in pellet production at 9 of 10 mills in the region;
- Harvest levels. The results described in this summary are based on forest harvesting at 2015 levels, with the assumption that increased demand for pellet fiber is offset by reductions in other markets (see page 2) for no net increase in harvesting;
- Tree regrowth; and
- Forest dynamics and natural impacts that can affect unharvested trees and result in release of stored carbon.
Measuring the greenhouse gas impact of any heating fuel requires accounting for all emissions in production and use of the fuel, including:
- All the greenhouse gases associated with producing the fuel (including extraction or harvesting, manufacturing or processing, transportation);
- Greenhouse gases emitted by the fuel when used;
- Efficiency of the heat generation system being used; and
- Carbon stocks in the forest such as live and dead trees (in the case of using wood).
SIG-NAL used US Forest Service forest inventory data to define forest types and age classes for 2 representative wood supply areas within a 50 mile radius of the pellet plant, and used growth and yield projections from the Northeast Variant of the US Forest Service Forest Vegetation Simulator (FVS-NE) to examine the results of forest management options. SIG-NAL derived initial stand type and tree lists from Maine FIA plot data, which due to similarities across the Northern Forest, provided a reasonable estimation of growth response to management at the landscape scale. SIG-NAL used a new pellet life cycle assessment module for the ForGATE Forest Sector Greenhouse Gas Assessments Tool for Maine1 to calculate total emissions for scenarios with and without pellet mills. (1Hennigar, C., L. Amos-Binks, R. Cameron, J.S. Gunn, D.A. MacLean, and M. Twery. 2013. ForGATE - A Forest-sector GHG Assessment Tool for Maine: Calibration and Overview. Gen. Tech. Rep. NRS-116.
Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 54
Why markets for wood pellets help save forests from development
Changing markets make room for pellet production
Forests—and changing markets—provide the opportunity to reduce greenhouse gas impacts by heating with local, renewable wood pellets instead of fossil fuels.
Major traditional markets for low-grade wood, such as paper making, continue to shrink in the Northern Forest. The drop in demand creates an opportunity to shift pulpwood toward pellet manufacturing.
- Eleven pulp mills have closed in the Northern Forest since 1999, reducing demand for low-grade pulpwood.
- Between Oct. 2013 and April 2016, Maine lost 4 million tons, or 36%, of its low-grade wood market. Most of this reduction is not reflected on harvest volume graph at right.
Landowners rely on markets for low-grade wood that is harvested to improve long-term timber production, recreation and more. Pellets are an important part of the low-grade wood market. Steady markets for low-grade wood help landowners maintain forestland instead of converting it to non-forest uses such as development. See how we're working to drive demand for efficient pellet heat.
Forest volume context
An analysis of 2015 forest inventory data shows that the live volume of timber in forests in Maine, New Hampshire, New York, and Vermont is increasing. Annual forest net growth exceeds annual harvest.
- Net Growth: 21.6 million cords annually.
- Harvest: 12.6 million cords annually.