CARBON DIOXIDE & BIOMASS ENERGY

Perhaps the greatest environmental benefit of burning biomass for energy is its positive impact in moderating climate change.

Biomass C0₂.pdf

Carbon dioxide (CO₂) buildup in the atmosphere is one of the leading causes of global warming. When biomass is used sustainably to displace fossil fuels, the net impact is a lower CO₂ level in the atmosphere.

This is because burning fossil fuels takes carbon that was locked away underground (as crude oil, gas, and coal) and transfers it to the atmosphere as CO₂. Wood combustion, however, recycles carbon that was already in the natural carbon cycle, the net effect being that no new CO₂ is added to the atmosphere as long as the forests from which the wood came are sustainably managed.

Most biomass fuel is produced within an average human lifetime, and is therefore considered an active component of the global carbon cycle, a process that transports carbon in various forms throughout the earth’s natural systems. Significant quantities of CO₂ are absorbed by plants through photosynthesis, and then released through plant decay. Removing biomass fuel from forests using sustainable forestry practices stimulates the growth of replacement wood. This replacement growth absorbs approximately the same amount of CO₂ as was released during combustion.

The US Environmental Protection Agency reports, “CO₂ from this source [biomass] is generally not counted as greenhouse gas emissions because it is considered part of the short-term CO₂ cycle of the biosphere.” Fossil fuels, such as coal, oil, or natural gas deposits, are produced within a geologic timeframe. The carbon in these long-term deposits is considered ‘sequestered’ from the global carbon cycle, and, when used for energy, add to the cycle additional new carbon that would have remained underground.

If a gas or oil heating system is converted to wood, net CO₂ emissions are reduced by 75-90 percent, depending upon how much of the fossil fuel use is displaced. For this reason heating with wood is a powerful tool for an institution or community interested in meaningfully addressing climate change and renewable energy through its energy use.

A large percentage of the biomass that is burned to generate energy is waste from the forest products industry, such as sawmill waste. This waste would also release CO₂, often along with methane (a greenhouse gas that is more potent than CO₂), while decomposing in landfills and waste piles. Therefore, using biomass waste to produce energy minimizes methane emissions while also both displacing fossil-fuel use and contributing no net CO₂ to the atmosphere.