Cradle-To-Gate Life Cycle Assessment of Switchgrass Fuel Pellets Manufactured in the Southeastern United States
AbstractDeveloping renewable energy sources with low environmental impacts is becoming increasingly
important as concerns about consuming fossil fuel sources grow. Cultivating, harvesting, drying,
and densifying raw biomass feedstocks into pellets for easy handling and transport is one step forward in this endeavor. However, the corresponding environmental performances must be quantified. This study presents cradle-to-gate life cycle inventory and impact assessment data for switchgrass fuel pellets potentially manufactured in the US Southeast. Because there are no current manufacturers of switchgrass pellets, inventory data were based on field trials of cultivation and harvest of switchgrass combined with a separate study of wood pelletization. Energy inputs for cultivation and harvest of switchgrass were collected by survey from farmers in Tennessee and represent the years 2008, 2009, and 2010. Data for pelletization were taken from a report on wood pellet manufacturing in the US Southeast. To produce 1.0 Mg of pellets that contain 18.0 GJ of potential bioenergy, 4.1 GJ of fossil energy inputs were required. Switchgrass crops require relatively little energy and inputs for the cultivation and harvest processes. The majority of
the environmental burdens are associated with drying and pelletizing the raw material.
The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:
1. All proprietary rights other than copyright, such as patent rights.
2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.
3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.