Low-CO 2 Electricity and Hydrogen: A Help or Hindrance for Electric and Hydrogen Vehicles? T. J. WALLINGTON,* ,† M. GRAHN, ‡ J. E. ANDERSON, † S. A. MUELLER, † M. I. WILLIANDER, § AND K. LINDGREN ‡ Systems Analytics and Environmental Sciences Department, Ford Motor Company, Mail Drop RIC-2122, Dearborn, Michigan 48121-2053, Department of Energy and Environment, Physical Resource Theory, Chalmers University of Technology, 412 96 Go ¨teborg, Sweden, and Department of Technology Management and Economics, Management of Organizational Renewal and Entrepreneurship (MORE), Chalmers University of Technology, 412 96 Go ¨teborg, Sweden Received July 31, 2009. Revised manuscript received December 15, 2009. Accepted February 4, 2010. The title question was addressed using an energy model that accounts for projected global energy use in all sectors (transportation, heat, and power) of the global economy. Global CO 2 emissions were constrained to achieve stabilization at 400-550 ppm by 2100 at the lowest total system cost (equivalent to perfect CO 2 cap-and-trade regime). For future scenarios where vehicle technology costs were sufficiently competitive to advantage either hydrogen or electric vehicles, increased availability of low-cost, low-CO 2 electricity/hydrogen delayed (but did not prevent) the use of electric/hydrogen-powered vehicles in the model. This occurs when low-CO 2 electricity/ hydrogen provides more cost-effective CO 2 mitigation opportunities in the heat and power energy sectors than in transportation. Connections between the sectors leading to this counterintuitive result need consideration in policy and technology planning. 1. Introduction Global climate change, caused by increasing levels of greenhouse gases in the Earth’s atmosphere resulting from human activities (1) is a major issue that society is facing. CO 2 released during fossil fuel combustion and deforestation is the largest contributor to the radiative forcing of climate change (1). The United Nations Framework Convention on Climate Change, ratified by 192 countries, calls for stabiliza- tion of greenhouse gas concentrations in the atmosphere at a level that would “prevent dangerous anthropogenic in- terference with the climate system”. Transportation is a critical economic sector in modern society and a significant source of CO 2 emissions. In 2004, light-duty passenger vehicles were responsible for ap- proximately 20%, 17%, and 11% of U.S., EU-15, and global fossil fuel CO 2 emissions, respectively (2). A transition to vehicles powered by electricity or hydrogen is being con- sidered to reduce CO 2 emissions (3–8). Electric- and hydrogen- powered vehicles operating on electricity or hydrogen derived from conventional fossil fuel sources offer limited CO 2 benefits. The development of low (fossil) CO 2 sources of electricity and hydrogen is needed for electric/hydrogen vehicles to offer significant CO 2 benefits. However, the development of sources of low-CO 2 electricity and hydrogen may offer CO 2 abatement opportunities that are more economically attractive in energy sectors other than trans- portation. Hence, while low-CO 2 sources of electricity and hydrogen are needed to facilitate a large-scale electric/ hydrogen vehicle fleet, the successful development of low- CO 2 electricity and hydrogen may delay the large-scale use of such fleets. To provide insight into the degree to which low-CO 2 electricity/hydrogen might accelerate, or delay, the wide- spread use of electric/hydrogen vehicles we have employed the Global Energy Transition (GET-RC 6.1) model (9). In our first study using the GET-RC 6.1 model, different fuel and vehicle technologies needed to achieve CO 2 stabilization at 400-550 ppm were investigated. Nine technology cost cases were considered and we found that variation of vehicle technology costs over reasonable ranges led to large differ- ences in the vehicle technologies utilized to meet future CO 2 stabilization targets. We concluded that given the large uncertainties in our current knowledge of future vehicle technology costs, it is too early to express any firm opinions about the future cost-effectiveness or optimality of different future fuel and vehicle powertrain technology combinations (9). In an extension of our previous work, we have considered two additional technology cost cases chosen to intentionally favor either electric- or hydrogen-powered vehicles to address the title question. Carbon capture and storage (CCS) is an energy technology that can facilitate the production of low-CO 2 electricity and hydrogen. Concentrating solar power (CSP) is a technology that is being developed to supply low-CO 2 electricity (10) and has the potential to become a relatively low-cost option. In the present study, CSP also serves as a proxy for other low-CO 2 electricity sources that may be developed in the future (e.g., wave, tidal, geothermal, advanced fission, or fusion plants). The impact of CCS and CSP availability in the model on the cost-effective passenger vehicle fuel and technology options necessary to achieve stabilization of atmospheric CO 2 at 400-550 ppm was investigated for the two cases. The goal of the present work was to provide a quantitative analysis of the impact of cost-effective low-CO 2 electricity/hydrogen on the adoption of electric/hydrogen vehicle technology in a carbon-constrained world. 2. Method The linear programming GET model constructed by Azar, Lindgren, and co-workers (11–14) covers the global energy system and is designed to meet exogenously given energy and transportation demand levels while stabilizing at a specific atmospheric CO 2 concentration at the lowest total system cost. While there is no explicit trading of CO 2 emission allocations in the model, the cap on total emissions and the minimization of total system cost in the model provides a result which by definition is indistinguishable from that obtained under a perfect global cap-and-trade system. The model does not consider greenhouse gases other than CO 2 . Regional energy demand in the GET model is derived by combining projections of global population (increasing to 10 billion in 2050 and 11.7 billion in 2100), World Energy Council estimates of the development of per capita income (IIASA/WEC scenario C1) (15), assumptions regarding the * Corresponding author e-mail: twalling@ford.com. † Ford Motor Company. ‡ Department of Energy and Environment, Physical Resource Theory, Chalmers University of Technology. § Department of Technology Management and Economics, Man- agement of Organizational Renewal and Entrepreneurship (MORE), Chalmers University of Technology. Environ. Sci. Technol. 2010, 44, 2702–2708 2702 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 44, NO. 7, 2010 10.1021/es902329h  2010 American Chemical Society Published on Web 02/26/2010