Abstract

Growing international trade in wood pellets is one response to regional efforts to mitigate the global problem of climate change. With this growing use of wood energy, there is increased scrutiny of the associated environmental impacts and concern over possible unintended consequences (e.g., nonrenewable energy inputs) that may detract from the carbon savings provided by such renewable energy sources. The focus of this article is to present an accounting system for the embodied fossil fuels in wood energy systems. This system is based on life-cycle assessment methodology and could accommodate fairly the variability in fossil fuel inputs for various bioenergy systems. Such a system could be incorporated into biofuel subsidies or carbon taxation policies. We use three scenarios as examples to illustrate (1) that wood-to-energy systems entail the use of fossil fuels and that the amount of this “embodied fossil carbon” varies with the processing inputs and transportation required and (2) that carbon tax/biofuel subsidies can be adjusted to accommodate variations in embodied fossil carbon. The growth in life-cycle databases and the advent of environmental product declarations make embodied fossil fuel calculations such as those presented here an increasingly practical component of biofuels policy development.