IEEE TRANSACTIONS ON SYSTEMS, MAN, AND CYBERNETICS—PART C: APPLICATIONS AND REVIEWS, VOL. 35, NO. 3, AUGUST 2005 391 The Life Cycle CO Emission Performance of the DOE/NASA Solar Power Satellite System: A Comparison of Alternative Power Generation Systems in Japan Hitoshi Hayami, Masao Nakamura, and Kanji Yoshioka Abstract—Solar power generation and, in particular, space solar power generation seem to be one of the most promising electric power generation technologies for reducing emissions of global warming gases (denoted collectively as CO emissions below). Cal- culating the precise amount of net reduction in CO emissions of a solar power system over other alternative power systems requires careful life cycle considerations. For example, emissions from a space solar system must include the emissions from consuming rocket fuel during the launching the satellites, and the emissions from the energy consumed while producing the solar panels. In this paper, we calculate the CO emissions observed through the life cycle of a solar power satellite (SPS). This life cycle consists of the production of rocket fuel and solar panels and the construction of a Rectenna (power receiving antenna), satellite, and all other equipment listed in the Department of Energy/NASA reference system. The calculation also includes indirect CO emissions that occur in various stages of production of these materials. Our baseline scenario shows that the life cycle CO emissions for an SPS system per unit of energy generated are almost the same as the emissions for nuclear power systems and are much less than the life cycle emissions for LNG-fired and coal-fired power generation systems. Furthermore, our SPS-Breeder scenario, in which SPSs supply electricity for producing further SPS systems, shows significantly lower CO emissions. As electrical power generation constitutes one fourth of Japan’s total CO emissions, reducing emissions from electric power generation is one of the most important issues on Japan’s policy agenda for dealing with global warming. Our findings suggest that the SPS is the most effective alternative power generation technology. Index Terms—Alternative technology, CO emissions, Depart- ment of Energy (DOE)/NASA reference system, life cycle assess- ment (LCA), power generation, solar power satellite (SPS). Manuscript received May 25, 2001; revised May 28, 2003, March 7, 2004, and September 14, 2004. This work was supported in part by the Environmental Conservation in the Asian Region project funded by the Research for the Future Program of the Japan Society for the Promotion of Science and a Social Science and Humanities Research Council of Canada research grant. This paper was recommended by Associate Editor K. Hipel. H. Hayami is with the Faculty of Business and Commerce and the Keio Economic Observatory, Keio University, Tokyo, Japan 108-8345 (e-mail: hayami@sanken.keio.ac.jp). M. Nakamura is with the Faculty of Applied Science, Department of Elec- trical and Computer Engineering, Sauder School of Business and the Institute of Asian Research, University of British Columbia, Vancouver, BC V6T 1Z2 Canada (e-mail: masao.nakamura@sauder.ubc.ca). K. Yoshioka is with the Keio Economic Observatory, Keio University, Tokyo, Japan 108-8345. Digital Object Identifier 10.1109/TSMCC.2004.843232 I. INTRODUCTION I N RECENT years, global warming caused by the green- house effect has raised serious policy questions as to what should be done to reduce emissions of global warming gases. Global warming gases (denoted collectively as CO emissions below) are generated when fossil fuels are burnt by consumers and by industry in the intermediate stages of production of goods and services. 1 In particular, CO is generated by elec- tric power generation, industrial production activities, use of automobiles, construction and other human activities. In most countries the economic activity that emits the largest amount of CO is electric power generation. For example, electricity generation accounts for about 25% of Japan’s 1.2 billion tons of annual CO emissions. As life cycle assessment (LCA) analyses of CO emissions show [1], [2], many production activities that directly release only small amounts of CO nonetheless use large amounts of electricity. For example, driving electric vehicles does not release CO , but they depend on batteries which must be charged. If electricity is generated mainly from coal burning, driving electric cars will indirectly emit large amounts of CO . Developing an electric power generation system that uses little fossil fuels and emits small quantities of CO is, therefore, of urgent importance. 2 In this paper, we estimate the life cycle CO emission per- formance of a solar power satellite (SPS) system, one possible source of Japan’s electric power in the future. These satellites must of course be launched using rockets, and production of their photo-voltaic panels also uses large quantities of energy. In addition,building a rectenna, a microwave power receiving and rectifying antenna on Earth, requires large amounts of cement 1 We use CO equivalents to measure emissions of global warming gases in this paper. Emissions of global warming gases will be denoted collectively as CO emissions. 2 One way to encourage energy efficiency and effective use of less polluting equipment globally is to trade emission rights, as is proposed in the Kyoto pro- tocol (e.g., [3]). The Kyoto protocol, of which the U.S. is not a participating member, is expected to become a treaty for most developing and developed countries in the world. It will require developed countries to keep their CO emission levels to the levels below those for 1990. For example, within the Kyoto framework, both Canada and Japan must bring down their CO emission levels over the period of 2008–2012 to levels that are 6% below their 1990 levels. Unlike some other waterborn and airborn pollutants, however, global warming gases cause no immediate health hazard to humans. They are, therefore, not yet receiving much attention as far as implementation of mechanisms to reduce the total amounts of such gases emitted globally is concerned. 1094-6977/$20.00 © 2005 IEEE