Forest Fuels

A six-month study commissioned by the Massachusetts Department of Energy and recently released by the Manomet Center for Conservation Studies has raised multiple questions about the role of biomass in a new, clean energy future. The Manomet study, Biomass Sustainability and Carbon Policy, strives to analyze the carbon impacts of using forest biomass for energy and adds a significant amount of research to findings that have long shown that the sustainable use of renewable forest biomass for energy over time does not increase carbon in the atmosphere. In fact, the study reaffirms a basic tenet of renewable energy policy by showing that biomass for energy results in significant carbon benefits, especially when compared with fossil fuels, because unlike the latter, it recycles atmospheric carbon.

But the study is not without its shortfalls. The study asserts that greenhouse gas emissions (GHGs) from power generation are greater in the near-term for biomass than for fossil fuels, and that net reductions in GHGs from biomass energy relative to fossil energy do not become apparent for many years. However, that conclusion is based on an overstatement of near-term GHG emissions from biomass by focusing only on forest plots that are harvested in any given year, ignoring carbon uptake across the broader landscape that is going on simultaneously and has exceeded the removal of carbon for many years.

The Manomet study acknowledges that although forest biomass releases carbon when it is used for energy, it is unique because, unlike fossil fuels, forests can grow back and recapture (or sequester) carbon from the atmosphere. Over time, accelerated forest growth is paying off this so-called “carbon debt,” making the use of wood for energy increasingly beneficial for greenhouse gas mitigation. The benefits have been acknowledged by EPA, which concluded in May, 2009, that carbon “emitted from biomass-based fuels combustion does not increase atmospheric [carbon] concentrations, assuming the biogenic carbon emitted is offset by the uptake of [carbon] resulting from the growth of new biomass.” And the California Public Utilities Commission noted in 2007 “that electric generation using biomass that would otherwise be disposed of under a variety of conventional methods (such as open burning, forest accumulation, landfills, composting) results in a substantial net reduction in GHG emissions.”

Because the Manomet study bases its assumptions on the use of new wood  harvested exclusively for the generation of power, it ignores the real-world practice of the industry, which is primarily using residual materials from forestry, agriculture and urban wood waste, including tops and limbs left after more valuable traditional timber harvesting is completed. On average, the biomass power industry removes 68.8 million tons of forest waste annually, improving forest health and dramatically reducing the threat of forest fires. By using this waste to generate electricity, the biomass power industry is preventing the need for open burns and reducing carbon dioxide and methane, a very potent greenhouse gas.

Another shortfall of the Manomet study is its focus on the on the wrong threat. The attention to the so-called “carbon debt” ignores the bigger carbon implication stemming from the loss of the trees permanently to other uses, be they shopping centers, housing developments, even soybean fields, because the private landowner no longer has markets for timber and is forced to convert the land to other uses. Bioenergy development gives the forestland owner an outlet for waste material as pulpwood and sawtimber markets continue to shrink. Preventing the loss of private timberlands to land conversion should be foremost in this debate.

The prevailing science is clear on the carbon benefits of producing energy from sustainable forest biomass as compared to fossil fuels. Over the long term our nation will be better served by increasing its use of an energy source, like excess forest biomass, that recycles atmospheric carbon than burning more fossil fuels that don’t.

Re-post from: [http://blog.25x25.org/?p=1625]