Scenario uncertainties in estimating direct land-use change emissions in biomass-to-energy life cycle assessment Aimee E. Curtright a, *, David R. Johnson b , Henry H. Willis a , Timothy Skone c a RAND Corporation, 4570 Fifth Ave., Suite 600, Pittsburgh, PA 15213, USA b RAND Corporation, 1776 Main St., PO Box 2138, Santa Monica, CA 90405-2138, USA c National Energy Technology Laboratory, 626 Cochrans Mill Rd., PO Box 10940, Pittsburgh, PA 15236-0940, USA article info Article history: Received 22 November 2011 Received in revised form 29 June 2012 Accepted 13 September 2012 Available online 9 November 2012 Keywords: Bioenergy Biofuels Greenhouse gas emissions Uncertainty analysis Life cycle assessment Land use change abstract The use of biomass for energy production has increasingly been encouraged in the United States, in part motivated by the potential to reduce greenhouse gas (GHG) emissions relative to fossil fuels. However, the GHG-intensity of biomass-derived energy is highly dependent on how the biomass is obtained and used. We explore scenario uncertainty in GHG estimates in the Calculating Uncertainty in Biomass Emissions (CUBE) model and find that direct land-use change emissions that result during the biomass production often dominate the total “farm-to-hopper” GHGs. CUBE represents each land-use change deci- sion as a conversion of land from one of four specified baseline ecosystem to produce one of seven feedstock crops, both distinct by geographic region, and then determines the implied changes in soil organic carbon, root carbon, and above-ground biomass. CUBE therefore synthesizes and organizes the existing literature to represent direct land-use change emissions in a way that can be more readily incorporated into life cycle assess- ment. Our approach to representing direct land-use change literature has been applied to a specific set of data and offers immediate implications for decisionmakers, but it can also be generalized and replicated in the future, making use of improved scientific data on the magnitude and rates of direct land-use change emissions as it becomes available. ª 2012 Elsevier Ltd. All rights reserved. 1. Introduction The use of biomass for energy production has increasingly been encouraged in the United States. Tax incentives, loan and grant programs, regulatory requirements, and mandates have all been used to promote the use of biomass for energy production in recent years, especially in the case of biofuels [1]. For example, a national Renewable Fuel Standard (RFS) was first introduced in the Energy Policy Act (EPACT) of 2005 and was expanded to the RFS2 by the Energy Independence and Security Act (EISA) of 2007, requiring that minimum amounts of renewable fuels (e.g., ethanol and biodiesel) be used for transportation fuel. One impact of RFS2 has been greatly expanded production of biofuels, especially ethanol, in the U.S [2]. Additionally, the majority of states have enacted Renewable Portfolio Standards (RPSs) or state-level renewable electricity goals. In all cases, one or more form of biomass qualifies toward meeting these RPS requirements [3]. Various forms of a federal RPS have also been proposed. A number of motivating factors have been cited for expanding the use of renewables in general, and biomass in particular, for fuel and electricity production. These include potential environmental benefits, including reducing green- house gas (GHG) emissions; reductions in oil imports and * Corresponding author. Tel.: þ1 412 683 2300; fax: þ1 412 683 2800. E-mail address: acurtrig@rand.org (A.E. Curtright). Available online at www.sciencedirect.com http://www.elsevier.com/locate/biombioe biomass and bioenergy 47 (2012) 240 e249 0961-9534/$ e see front matter ª 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.biombioe.2012.09.037