Peter Tittmann

A Framework for Assessing the Life Cycle Greenhouse Gas Benefits of Forest Bioenergy and Biofuel in an Era of Forest Carbon Management

The use of forest wastes for the production of bioenergy and liquid biofuels has the potential to offset the use of fossil energy sources. Some studies suggest biofuel and bioenergy produced from the removal of forest waste—products considered to be uneconomical to harvest—generates significant well-to-tank greenhouse gas (GHG) emission savings by displacing energy produced from fossil resources. In parallel, an increase in the frequency and intensity of wildfire both empirically observed and predicted by climate change models has highlighted the need to actively manage forests to increase the resilience of forests to wildfire. Integrated analysis that takes into account the dynamic interactions between carbon (C) pools resulting from forest management practices; forest fire behavior; and the fate of forest biomass in debris, forest products, and energy production will provide a consistent framework for policy planning that maximize the overall benefits of GHG policy. This integrated approach will have a better chance of balancing the trade-offs and maximizing synergies between C management and sustainability goals. This article outlines a life cycle accounting framework for evaluating the GHG benefits of utilizing forest biomass for bioenergy production under various forest management strategies.

Economic impact of combined torrefaction and pelletization processes on forestry biomass supply

The cost of supplying wood biomass from forestry operations in remote areas has been an obstacle to expansion of forest‐based bioenergy in much of the western United States. Economies of scale in the production of liquid fuels from lignocellulosic biomass feedstocks favor large centralized biorefineries. Increasing transportation efficiency through torrefaction and pelletization at distributed satellite facilities may serve as a means to expand the utilization of forestry residuals in biofuel production. To investigate this potential, a mixed‐integer linear program was developed to optimize the feedstock supply chain design with and without distributed pretreatment. The model uses techno‐economic assessment of scale‐dependent biomass pretreatment processes from existing literature and multimodal biomass transportation cost evaluations derived from a spatially explicit network analysis as input. In addition, the sensitivity of the optimal system configuration was determined for variations of key input parameters including the production scale of pretreatment facilities, road and rail transportation costs, and feedstock procurement costs. Torrefaction and densification were found to reduce transportation costs by

Development of a biorefinery optimized biofuel supply curve for the Western United States.

0.84 per GJ and overall delivered costs by

A spatially explicit techno-economic model of bioenergy and biofuels production in California

0.24 per GJ, representing 14.5% and 5.2% cost reductions compared to feedstock collection without pretreatment. Significant uncertainties remain in terms of the costs associated with deploying torrefaction equipment at the scales modeled, but the level of potential cost savings suggests further analysis and development of these alternatives.