Wood pellets and climat change

Biomass fuels, including wood pellets (and other wood fuels, such as regular cordwood and wood chips) are generally recognized as having far lower net lifecycle carbon dioxide emissions than fossil fuel equivalents, to the order of 98% fewer emissions.

The release of CO₂ from burning sawdust, when derived from forest biomass from well managed forest ecosystems, is carbon-neutral. The carbon in these ecosystems regularly cycles between standing, stored terrestrial carbon and free atmospheric carbon in the transition from regrowth to maturity, decline, decomposition/destruction and regrowth.

 Wood/plant biomass is made up of mostly carbon (and water). Carbon came from the carbon dioxide absorbed from the atmosphere by the tree or grass while it grew through the process of photosynthesis, and the carbon returns to the atmosphere when the wood is either burned or left to decompose. It is true that in combustion, most of the carbon joins with oxygen and returns to the atmosphere as carbon dioxide. But - if the wood is instead left to decompose through natural processes, the carbon still partially returns to the air – but also in the form of the gas methane (CH₄), which causes 21 times more damage to the climate over 100 years than the same quantity of CO₂ does over 100 years. Only part of the decaying wood is released as methane; other parts stay within the soil and often improve it substantially over time.

 Secondary emissions related to pellet manufacture also have a carbon impact, with the release of carbon involved in the harvesting, manufacturing, and process of transport to the end-user for these pellets and other biomass fuels (known as grey energy) - though these emissions can be reduced to a minimum by using other forms of ‘green’ energy (solar, wind, biodiesel,…).

The United States forest products industry, with apparent justification, fears that if massive use of wood as a fuel is instituted, forestry will no longer be able to be sustainably managed, and may result in ecological devastation. This is especially the case if wood is extensively used to generate electricity, though this would probably not be in the form of wood pellets.

Still, the combustion of sustainably managed and harvested wood or biomass is generally considered to represent one of the best practical and available means for sustainable use of low net-carbon combustion for economic sectors that require the use of combustion. The medium of wood or biomass pellets as a form of energy transfer provide a fungible, mass-producible, commerce-ready product capable of putting sustainable biomass combustion technology to work for the modern-day consumer - and, in many cases, wood/biomass pellets are less expensive and nearly as convenient as other fuel sources.

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