Life Cycle Analysis of Biomass Transportation: Trains vs. Trucks 2005-01-1551
Biomass is regarded as a renewable resource for upgrading to solid or liquid fuels or for electricity generation. Because its energy density is very low compared to petroleum or coal, the cost of transporting biomass is a significant part of the total biomass cost. For this reason it is usually regarded as a local resource. However, appropriate logistic systems may allow collection of biomass over a large geographical area, thus making it possible to consider efficient, large scale energy conversion systems. For areas without significant water transportation, the basic choices are between truck-based, train-based and pipeline transportation. Previous work has shown that pipeline transport is not effective for biomass delivery due to uptake of carrier fluid (water or oil) by the biomass. Hence, the choice becomes one between train and truck transport.
Western Canada has large resources of wood, forest harvest residues (limbs and tops of trees harvested for pulp or lumber), and agricultural residues such as wheat and barley straw. Effective use of these resources requires an economic plant size, determined by a previous study to be 250 MW for a straw-fired power plant or 130 MW for a forest residues plant. For typical Alberta biomass production densities, the collection radius for these bio-energy plants is 495 km for forest residues and 125 km for straw. This study uses a published life cycle analysis (LCA) results to investigate the environmental load for biomass transport to these optimum-sized plants. All biomass starts the journey from field to plant on a truck; this study evaluates the choice between truck-only or a combination of truck plus train transport for this sort of bulky, low value commodity.
The study results favor train over truck, with reductions in emissions of 70% or more per tonne km. European economic studies suggest a transition distance at which truck and train transport is more economic than truck only. As an added feature, train transport alleviates a potential problem in truck congestion at biomass processing plants. While this study focuses on biomass-for-energy, a similar approach may be useful for other bulky comodities which requiere transportation from a distributed region to a central plant.