Heating With Wood - Pt 1

Posted on 19th November, 2010

Wood Energy Use Cuts Greenhouse Gas Emissionstreetops - birch forest

Wood is considered a renewable fuel, which is obvious considering new trees grow to replace those harvested. What may not be quite so obvious, however, is that heating with wood does not contribute to climate change the way fossil fuel use does. When oil, gas and coal are burned, the carbon they contain (which was absorbed from the atmosphere by plants millions of years ago) is oxidized to carbon dioxide (CO2), the main greenhouse gas (GHG). The combustion of fossil fuels releases ancient carbon, thereby increasing the atmospheric concentration of CO2.

The Forest Carbon Cycle

Wood is about half carbon by weight but its use as a fuel is almost carbon-dioxide neutral because trees absorb CO2 as they grow. When trees mature, die and fall in the forest, and decompose there, the same amount of CO2 is emitted as would be released if they were burned for heat. In other words, decomposition (rot) is a slow form of oxidation whereas combustion in a woodstove or furnace is fast oxidation, with heat as a by-product. When considered over the normal forest regeneration period of 50 to 100 years, heating with wood can be considered almost CO2 neutral. In heating our houses with wood, we are simply tapping into the natural carbon cycle in which CO2 flows from the atmosphere to the forest and back. Therefore, when wood is burned as a substitute energy source for fossil fuels, a net reduction in GHG emissions results.

 

Obviously, the answer to these assumptions are not entirely simple – and a future blog will deal with facts and figures.

 

Any queries, suggestions or comments? – Please let me know.

 

‘Bye for now,

Les O’Donnell.

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