Life Cycle Analysis of Bioenergy

There are many potential benefits of bioenergy, and many potential negative effects as well.  Public interest in bioenergy development includes direct and indirect consequences for:

  • the environment
  • community
  • quality of life
  • economic development
  • human health
  • greenhouse gas (GHG) emisions
  • energy balance
  • water, land, and wildlife

Understanding these questions requires an ability to identify all potential effects from construction of a project, to the production, processing and transportation of feedstocks, to conversion technology, to the delivery and use of energy products and co-products, and to disposal of by-products and wastes (figure 3.1).

Figure 3.1. Impacts of bioenergy are measured across the supply chain as contributing to or impeding sustainability. (USDOE, Energy Efficiency and Renewable Energy Program.)

Life-cycle assessment (LCA) is an approach to evaluating the direct and indirect effects associated with a product or activity on human health and the environment in a cradle-to-grave appraisal of benefits and detriments. Life-cycle assessment examines the entire life span of a product or activity, from extraction of raw materials through production, transportation, use and disposal.  The LCA process is useful not only for understanding the specific impacts and net effect of bioenergy systems; it is an important tool for comparing alternative systems.  However, to date no single LCA has been able to comprehensively model all consequences of either a single bioenergy system or all bioenergy systems combined on all environmental, economic and societal realms at any particular location or for the earth as a whole.  While much research is needed to improve LCA methodology, it has become a widely heralded approach to quantitative analysis of bioenergy (see BIOEN2, Unit 2.3 for more on Life Cycle Assessment).