|Wood-burning appliances may make environmental sense, but only under certain conditions.|
|(cc) Gord McKenna|
To combat rising energy costs and further damage to our environment caused by the burning of fossil fuels, the trend for most people trying to heat their homes is to go high-tech: solar thermal and solar photovoltaic, wind turbines, and geothermal. Others have chosen to look to the past: the humble wood stove, upgraded with modern technology.
Old fashioned wood stoves were hardly an environmentally friendly way of heating a home, producing excessive smoke and soot, losing valuable heat up the chimney, and consuming vast quantities of wood. Modern wood stoves, however, may be as much as 95% more efficient than the old pot-bellied cousins your great-grandmother cooked on.
This is the finding of a study conducted by Dr. Paul Grogan, a plant and ecosystem ecologist at Queen’s University in Kingston, Ontario.
The study, conducted by Dr. Grogan and a team of students, is detailed in volume 38 of the Journal of Natural Resources and Life Sciences Education. It found that while gross CO2 emissions do increase with the use of a wood stove compared to heating a home with natural gas, net emissions are negligible.
Specifically, in the case study environment — a home in Kingston, Ontario examined over a 4-year period — gross CO2 emissions increased from 12,610 kg to 17,330 kg after the installation of the wood stove. However, net CO2 emissions were reduced by an almost equal amount, with the difference coming only from the harvesting and transportation of the wood.
The study also indicated that such a solution could make economic sense, with savings over fossil fuels in the area of 25% when rising fuel prices and carbon tax are factored in.
Realizing these benefits requires observing at least two critical factors: using a high-efficiency wood stove or wood-burning appliance, and harvesting the wood in a sustainable manner.
In North America, modern wood stoves should be certified by the U.S. Environmental Protection Agency or the Canadian Standards Association. Such appliances employ advanced combustion systems that preheat the combustion air and use an insulated firebox to keep temperatures high. They may also utilize a catalyst to burn the smoke as well as the wood, further reducing emissions.
Trees are considered a carbon-neutral fuel source; they emit carbon when they’re burned but they absorb carbon as they’re growing. Obviously, the net carbon release realized using wood stoves will only approach zero if sufficient trees are grown to replace those consumed.
The Queen’s University study estimated that, with an average growing time of 130 years for local tree species, a wood-lot of 3.5 hectares (8.64 acres) would be required to provide an indefinite supply of wood for a typical household without any net increase in carbon emissions.