Conflicting Goals: Energy Security vs. GHG Reductions Under the EISA Cellulosic Ethanol Mandate

Abstract

Increasing energy security and lowering greenhouse gas (GHG) emissions have been prominent goals in recent energy and environmental policies. While these goals are often complementary, there may also be cases where they conflict. A case in point is the Energy Independence and Security Act of 2007 (EISA). The goals of EISA are to increase the United States' energy independence and security as well as to increase the production of clean renewable fuels. Title II of EISA establishes mandates for increasing the use of low carbon fuels to replace gasoline. While the Title II mandates will meet the energy security goal of EISA, the mandate for the use of at least 16 billion gallons of cellulosic ethanol by 2022 may conflict with efforts to reduce substantially the nation's GHG emissions over the next 20 years. The nation's production capacity for biomass is likely to be limited and the use of biomass to replace coal in generating electricity yields 2 to 3 times the GHG reduction associated with using cellulosic ethanol to displace gasoline. Thus, there is a trade-off between the energy security gains of the biofuels mandate under EISA and the more effective (in terms of GHG emission reductions) use of biomass in the electric utility sector. One means of evaluating this trade-off is to examine the factors that affect the costeffectiveness of diverting biomass from electricity production to cellulosic ethanol production. This paper identifies some of the key factors that affect the cost-effectiveness of the energy security and climate change goals of EISA. The cost-effectiveness of EISA will depend on (1) constraints on biomass production, that is, the extent to which the EISA mandate may crowd out the use of biomass to generate electricity; (2) the world oil price (and the cost of production of cellulosic ethanol); and (3) the social cost of carbon.