Wednesday, December 10, 2008
The high cost of oil and gas fuels a boom in wood stoves, but is burning wood greener than burning gas?
An inordinate number of articles on-line from publications across the United States are reporting on the burgeoning interest in wood stove purchases and use. Despite our falling economy the rising price of non-renewable fossil fuels has provided an incentive to return to traditional wood burning for supplemental, or sometimes total, heating for the home.
Both traditional, pellet-burning, and even corn burning wood stoves are in high demand as cold weather returns to the northern United States and Canada. Sales of stoves are up 55 percent so far this year over last according to industry figures; sales of wood pellet stoves are even hotter: up 135 percent over the same period last year.
Coal, oil and natural gas are the three kinds of fossil fuels that we have mostly depended on for our energy needs, from home heating and electricity to fuel for our automobiles and mass transportation. Fossil fuels formed from plants and animals that lived hundreds of millions of years ago and became buried way underneath the Earth's surface where they transformed into the materials we depend on for fuel today. They are limited in supply and will one day be depleted. There is no escaping this fact. Therein lays the root of all our energy problems: fossil fuels are non-renewable.
The concept of renewable energy, or alternative energies, is growing at a steady rate. Renewable energy simply means energy that is produced from sources other than our primary energy supply: fossil fuels. Wood if properly maintained, harvested and burned, is an important source of renewable energy for those in colder climates.
Since 1988, all indoor wood stoves and fireplace inserts sold in the United States have been subject to U.S. Environmental Protection Agency (EPA) emission standards. EPA-certified units feature baffles or dampers, secondary combustion chambers, and/or secondary air supplies to improve combustion efficiency and reduce emissions. They use less wood to produce the same amount of heat, saving you money while reducing air pollution.
If you own a pre-1988 indoor wood stove, fireplace insert, or other wood-burning appliance, you can significantly reduce its emissions by adding a catalytic combustor or converter. Similar to the unit found in your vehicle's emissions control system, it will help burn gases, fine particles and soot before they are vented outside, for a cleaner, more efficient wood fire. Catalytic units should be inspected at least twice per year, both before and during peak home heating season.
Advanced combustion stoves and fireplaces use about 1/3 less wood and produce 90% less smoke to produce the same heat as earlier models. They actually re-burn the smoke, which produces more heat and eliminates the build-up of creosote. Consequently, advanced combustion burners require less maintenance than conventional stoves and fireplaces.
Ecologists generally agree that wood is carbon neutral. Burning wood releases a significant amount of the green house gas, carbon dioxide, which is also released by fossil fuels. The gas is reabsorbed by growing trees and turned into carbon, accounting for half the weight of wood. Whether a tree burns in your fireplace or decomposes in the forest, it will release the same amount of carbon into the environment in the form of CO2, methane, and other gases.
This cycle only closes, however, when the wood has been grown and harvested using sustainable forestry practices. Proper forestry practices preserve bio-diversity, which in turn enables the CO2 to be reabsorbed, as well as giving one a place to get more firewood. Theoretically, this practice can be repeated indefinitely. Fossil fuel can make no such claim.
By burning clean, dry, well-seasoned hardwoods such as oak or maple, your wood stove will produce less smoke, i.e. less pollution. An added advantage is that hardwoods provide more heat energy than softer woods because hardwoods are denser and burn more slowly and evenly. Poplar and birch are also good firewood. Seasoned wood is usually purchased by the cord (4 ft. x 8 ft. x 4 ft. ft of tightly stacked wood).
A fire made from wood that has been properly seasoned, is not wet or punky, and that is burning properly produces little or no smoke from the chimney. If you see a lot of smoke coming from a chimney, that's air pollution. Wood smoke results from incomplete burning. When released outdoors, or accidently indoors, it becomes air pollution. A properly installed, correctly used EPA certified wood stove releases significantly less pollution into the environment. EPA certified wood stoves burn wood more completely; therefore, they emit 60% to 80% less pollution. In some parts of the United States during a typical wood heating season, wood smoke can account for about 80% of the air pollution in a residential area.
So the answer is yes. If approached properly and treated as a renewable energy source sustained by practical forestry management, wood burning is definitely greener than burning fossil fuels.
Quick Tips on How to Burn Wood More Cleanly
The Environmental Protection Agency (EPA) has these following recommendations for people who burn wood:
• Use a properly installed and vented EPA-certified wood stove.
• Season wood outdoors through the summer and for at least six months.
Properly seasoned wood is darker, has cracks in the end grain, and sounds
hollow when smacked against another piece of wood.
• Store wood outdoors, stacked neatly off the ground with the top covered.
• Use clean newspaper and dry kindling to start fires.
• Have the wood stove cleaned and inspected annually.
• Don’t burn household trash or cardboard. Plastics and colored inks on
magazines, boxes, and wrappers give off toxic chemicals when burned.
• Never burn coated, painted, or pressure-treated wood, as it also releases
• Never burn ocean driftwood, plywood, particle board, or any wood with glue
on or in it. They all release harmful chemicals when burned.
• Never burn wet, rotted, diseased, or moldy wood.
• Only bring into your home the amount of wood needed for a day to reduce the
chance of allergy-causing mold spores circulating indoors.
• Breathing smoke is not healthy. Wood smoke contains a mixture of gases and
fine particles that can cause burning eyes, runny nose, and bronchitis. Fine
particles can aggravate heart or respiratory problems, such as asthma, in
people of all ages.
Resources: woodheat.org, The National Geographic’s http://www.thegreenguide.com, Environmental Protection Agency, ecology.com, terraapass.com