Discussion Paper

Comparative Life Cycle Assessments: Carbon Neutrality and Wood Biomass Energy

Apr 25, 2013 | Roger A. Sedjo


Biomass energy is expected to play a major role in the substitution of renewable energy sources for fossil fuels over the next several decades. The US Energy Information Administration (EIA 2012) forecasts increases in the share of biomass in US energy production from 8 percent in 2009 to 15 percent by 2035. The general view has been that carbon emitted into the atmosphere from biological materials is carbon neutral—part of a closed loop whereby plant regrowth simply recaptures the carbon emissions associated with the energy produced. Recently this view has been challenged, and the US Environmental Protection Agency (EPA) is considering regulations to be applied to biomass energy carbon emissions. A basic approach for analyses of environmental impacts has been the use of life cycle assessment (LCA), a methodology for assessing and measuring the environmental impact of a product over its lifetime—from raw material extraction through materials processing, manufacture, distribution, use, repair and maintenance, and disposal or recycling. However, LCA approaches vary, and the results of alternative methodologies often differ (Helin et al. 2012). This study investigates and compares the implications of these alternative approaches for emissions from wood biomass energy, the carbon footprint, and also highlights the differences in LCA environmental impacts.