Over the last two decades there has been an almost 50% increase in world energy consumption arguably because of (i) an approximate 45% increase in world population and (ii) worldwide improvement in economic activity and the consequent improvement in the standards of living. Human Development Index (HDI) and per capita energy consumption for a globally representative sample of countries, covering industrialized, developing and poorly developed regions for the year 2002 are plotted in Figure 1. The sample includes the most populous countries, which represent nearly 90% of world population and 90% of world energy consumption. The correlation points to large, additional energy requirements in the next two to three decades as the developing economies strive to compete with the developed economies and the least developed nations move ahead towards “developing nations” status. Clearly, substantial effort is needed to contain population increase, limit our energy consumption and to explore sustainable sources of energy if we are to maintain present standards of living in the developed countries and improve those of the developing countries.