The Environmental Impact

The environmental impact posed by pellets is comprised of two different stages: production and combustion.

Production

Pellets are composed primarily of wood and other biomass waste. It is using a resource that would either be discarded and left on the ground or placed in land fills. Therefore, simply because of its raw materials it is aiding in the green growth of the region (How are Pellets Made?).

Acquiring biomass waste such as leftover lumber materials, abandoned farm field grasses, or using biomass crops such as switchgrass requires the use of fossil fuels. Traditional farming techniques using diesel farm tractors for obtaining crops, and current logging methods using diesel log skidders and tractor trailers for moving wood are most practical. Obtaining these biomass fuels will not, however, result in a large influx in the use of fossil fuels because a new infrastructure system does not need to be established, it instead uses a pre-existing one.

Combustion

Pellet stoves are arguably one of the best available home and space heaters available. Pellet stoves are much more environmentally friendly than their wood stove and open fireplace cousins. While the first pellet stoves had increased efficiency, the current generation is far more efficient (Houck 13).

Using wood as a heat source has the lowest greenhouse gas emissions compared to all other space heating options, (oil, natural gas, kerosene, and propane.) By harvesting and using old and mature trees, there is less of a carbon footprint, and younger trees are able to grow up more quickly compensating for the carbon dioxide released in combustion (Houck 14).

Pellet stoves also have low acid precipitation. Acid precipitation is typically caused by high levels of sulfur and nitrous gases during the extraction and combustion processes. This is typically found when burning fossil fuels, and there is little fossil fuel use in combustion of pellet stoves. The also have virtually no contribution to ground-level-ozone because it is typically not associated with space heating due to its summertime nature  (Houck 14).

Carbon monoxide production is also reduced when using pellet burning stoves as compared to traditional wood burning stoves. The increased efficiency results in greater combustion and less emissions able to be released into the environment (Environmental Impacts of Renewable Energy Technologies).

There is very little solid waste produced from pellet stoves. The flame that exists in a pellet stove is a small intense flame that enables a more complete combustion than is possible in a conventional wood stove. This results in a much lower amount of unburned char left after burning. A pellet stove has about half a percent of it’s original mass left as ash compared to between one and five percent of the original mass with a conventional stove. EPA standards state that a typical pellet stove runs at approximately 78% efficiency where a wood stove runs at approximately 54% efficiency (Houck 16). Pellet stoves pollute at such a low level that they don’t require EPA certifications (Z).

The biggest environmental concern with pellet stoves is particulate emission. It is substantially less than that of conventional wood burning stoves, however it is not as low as heat by oil or gas combustion. However, oil and gas as heating fuels contribute to acid precipitation (Macintosh).

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Some Helpful Resources:

http://www.ci.mil.wi.us/ImageLibrary/Groups/cityDPW/general/docs/newsletters/environmentalFall09.pdf

http://www.guardian.co.uk/environment/cif-green/2009/apr/16/biomass-environment-agency1

http://publications.environment-agency.gov.uk/pdf/GEHO0305BIWI-e-e.pdf