A REVIEW AND FUTURE PROSPECTS OF RENEWABLE ENERGY IN THE GLOBAL ENERGY SYSTEM 1 D. Yogi Goswami John and Naida Ramil Professor Co-Director, Clean Energy Research Center, University of South Florida, Tampa, Florida, USA goswami@eng.usf.edu ABSTRACT This paper reviews global energy use in the past few decades and projections for future use based on the trends in recent years. The paper also reviews the present status of available energy resources and projections of how long they are expected to last in the future. Based on the future global energy needs, the availability of conventional resources and potential global climate change, renewable energy may have to provide for as much as 50% of the energy needs by 2050. Finally, this paper describes the present status of renewable energy use and describes renewable energy might provide the energy needs of the future. 1. INTRODUCTION Global energy consumption in the last half century has rapidly increased and is expected to continue to grow over the next 50 years, however, with significant differences. The past increase was stimulated by relatively “cheap” fossil fuels and increased rates of industrialization in North America, Europe and Japan; yet while energy consumption in these countries continues to increase, additional factors make the picture for the next 50 years more complex. These additional complicating factors include China and India’s rapid increase in energy use as they represent about a third of the world’s population; the expected depletion of oil resources in the near future; and, the effect of human activities on global climate change. On the positive side, the renewable energy (RE) technologies of wind, bio-fuels, solar thermal and photovoltaics (PV) are finally showing maturity and the ultimate promise of cost competitiveness. ____________________________________________ 1 This paper is an abridged version of Chapter 1 of The Handbook of Energy Efficiency and Renewable Energy, Eds. Frank Kreith and D. Yogi Goswami, CRC Press, 2007. 2. GLOBAL ENERGY DEMAND The total Primary Energy Demand in the world increased from 5,536 GTOE in 1971 to 10,345 GTOE in 2002, representing an average annual increase of 2% (Figure 1). 0 2,000 4,000 6,000 8,000 10,000 12,000 1971 2002 Year MTOE Other Renew ables Biomass and Waste Hydro Nuclear Gas Fig. 1: World Primary Energy Demand (MTOE) (Data from World Energy Outlook, 2004, IEA). However, it is important to note that the average worldwide growth from 2001 to 2004 was 3.7% with the increase from 2003 to 2004 being 4.3%. The rate of growth is rising mainly due to the very rapid growth in Pacific Asia which recorded an average increase from 2001 to 2004 of 8.6%. More specifically, China increased its primary energy consumption by 15% from 2003 to 2004. Unconfirmed data show similar increases continuing in China, followed by increases in India. Fueled by high increases in China and India, worldwide energy consumption may continue to increase at rates between 3% - 5% for at least a few more years. However, such high rates of increase cannot continue for too long. Even at a 2% increase per year, the primary energy demand of 10,345 GTOE in 2002 would double by 2037