Leading scientists call for careful carbon calculations as part of renewable energy plans

By Bob Berwn/Summit CountyCitizens Voice

SUMMIT COUNTY — Biomass energy from beetle-killed trees is often touted as a possible win-win scenario in Summit County, as the pine beetle epidemic threatens to leave the area eyeball-deep in forest debris. But it’s not quite as simple as chopping up the wood and feeding it into wood-fired boilers.

A group of leading American scientists recently sent a letter to Congress outlining some of the concerns with the federal energy bill as it relates to biomass. Extensive use of biomass could result in increased greenhouse gas emissions without an accurate accounting of carbon dioxide emissions from biomass conversion to energy.

Moving ahead with large-scale biomass energy plans without understanding the carbon cycle risks putting more carbon dioxide into the atmosphere, the scientists said. For Summit County, extensive use of dead lodgepoles as fuel would need to be balanced with aggressive reforestation efforts, otherwise, the carbon emissions from using the wood as fuel would outweigh any benefits.

To complicate the equation even more, the emissions from leaving the wood on the ground to decompose must also be calculated.Replacing fossil fuels with bio-energy does not directly  stop  carbon  dioxide  emissions  from   tailpipes  or  smokestacks. It may reduce other sources of emissions. But it also results in its own emissions, which which  may  even be higher per unit  of energy because of the  lower energy-to -carbon  ratio  of biomass.

Energy from biomass only reduces  atmospheric carbon dioxide if land and plants are managed to take up additional carbon dioxide beyond what they would  absorb without  bio-energy. In other words, before rushing ahead with plans to convert dead lodgepole forests to energy, land managers just accurately measure the carbon emissions that will result from burning the wood.

The letter explains that planting  fast-­‐growing energy crops on otherwise  unproductive land leads to additional  carbon absorption by  plants  that offsets emissions from  their use for energy without displacing carbon storage  in plants and soils. Read the letter here.

The Natural Resources Defense Council also published a fact sheet that explains the carbon calculations, Read it here. NREL’s  basic biomass energy page is here.

But clearing forests for energy, either to burn trees directly, or to replace forests with bio-energy crops actually results in releases of sequestered carbon to the atmosphere, just like the extraction and burning of fossil fuels. That creates a carbon debt and reduces ongoing  carbon uptake by the forest, with a net increase in greenhouse gas emissions that could undercut needed greenhouse gas emissions for several decades.

The scientists are not opposed to using biomass for energy production. In fact, the National Academy of Sciences says there is great potential for significant energy  production from  the  right  sources. But biomass measures must  include a system to differentiate emissions from bioenergy based on the source of the biomass.

Part of the problem is that many international treaties and domestic laws assume that all biomass energy results in a 100 percent reduction in emissions, regardless of the source. Thus, biomass has been exempted from emission caps in many cases. This also holds true for rules set for utility companies, which view biomass as a renewable energy source even if the biomass doesn’t reduce greenhouse gas emissions.

The lesson is that any legal measure to reduce greenhouse gas emissions must include a system to differentiate emissions from bioenergy based on the source of the biomass. The National Academy of Sciences has estimated significant potential energy production from the right sources of biomass4. Proper accounting will provide incentives for these sources of bioenergy.