Wood-Chip Heating Systems - Biomass Energy Resource Center

Older Residential Stove 1
EPA Certifi ed Stove 2
Particulate Matter from Various Wood Combustion Systems
Pellet Stove 3
Industrial Wood Boilers 4
School-sized Boilers 5
McNeil Generating Plant 6
.005
1 Calculations by Biomass Energy Resource Center, based
on EPA AP-42 data for a mix of pre-certifi cation and
post-certifi cation residential wood stoves and on
school wood energy systems characterized in note 2.5
(below).
2,3 U.S. Environmental Protection Agency. Compilation
of Air Pollutant Emission Factors, AP-42, Fifth Edition,
Volume I: Stationary Point and Area Sources: External
Combustion Sources, Residential Woods Stoves:
Final Section; Table 1-10.1: Pre-Phase I Non-Catalytic
(SCC 21-04-008-050), Phase II Non-Catalytic (SCC
21-04-008-050), Pellet Stove Type (Certifi ed) (SCC 21-
04-008-053), (PM10) at 5100 BTU/lb (dry wood value)
and 40% moisture content.
4 U.S. Environmental Protection Agency. Compilation of
Air Pollutant Emission Factors, AP-42, Fifth Edition,
a child attending a wood-heated school is negligible
compared to the risk of living in a home where a wood
stove is in regular use. Children are also at much
greater risk from particulate matter in the exhaust of
idling school buses than from wood heating plant
emissions.
CLIMATE CHANGE
The greatest environmental benefi t of burning
wood for energy is in its positive impact in moderating
climate change. CO2 buildup in the atmosphere is
the primary cause of global climate change. Fossil
fuel combustion takes carbon that was locked away
underground (as crude oil and gas) and puts it in the
atmosphere as CO2. When wood is burned, however, it
recycles carbon that was already in the natural carbon
cycle. The net effect of burning wood fuel is that no
new CO2 is added to the atmosphere, as long as the
forests from which the wood came are sustainably
managed. Therefore, when wood replaces fossil
0 0.5 1.0 1.5 2.0 2.5
3.0
Lbs/million Btu Input
Volume I: Stationary Point and Area Sources: External
Combustion Sources, Wood Residue Combustion
Boilers: Final Section; Table 1.6-1: Bark and Wet Wood
Mechanical Collector, Filterable PM 10.
5 Holzman, Michael I. Richard S. Atkins, Leigh A.
Gammie. 1996. Wood-Chip Fired Furnaces Testing Project
Air Emissions Testing and Public Health Impacts Analysis.
Coalition of Northeastern Governors, Washington D.C.
13-14 pp. Average of all tests (PM10).
6 Clean Air Engineering PM Tests (EPA standard) of the
Joseph C. McNeil Generating Station, Burlington,
Vermont, 1988. (Average of test results)
Note: The values in the graph represent uncontrolled stoves and
controlled boilers/power plant. This represents the situations
most often found in the fi eld.
fuel, the net impact is to reduce CO2 levels in the
atmosphere signifi cantly.
For a school district or other public building owner
interested in meaningfully addressing climate change
and renewable energy through its energy use, heating
with wood is a powerful tool. Making the building
itself more effi cient is always an excellent strategy for
addressing fuel consumption and CO2 emissions.
This approach may reduce heating fuel use (oil or gas)
and related CO2 emissions by 10-20 percent. However,
if the heating system is converted to wood fuel, CO2
emissions are reduced by 75-90 percent.
OTHER EMISSIONS
Oxides of sulfur (SOx) cause acid rain. Modern
wood systems have one sixth the SO2 emissions of fuel
oil. Oxides of nitrogen (NOx) cause ozone, smog, and
respiratory problems. Wood and fuel oil combustion
have similar levels of NOx emissions.
All fuel combustion processes produce carbon
WOOD CHIP HEATING SYSTEMS
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