Energy: Yesterday, Today, and the Opportunities and Challenges of Tomorrow

Abstract

As energy consumption has increased over the past 200 years, energy fuels have become cleaner and consumption more efficient. Fossil fuels currently supply approximately 85% of the energy needs of the world and 80% of the energy needs of the United States. Crude oil, a transportation fuel, supplies about 40% of the energy needs of the U.S., with 56% imported from other nations. Natural gas and coal each supply nearly a quarter of our energy needs. Half of the nation's electricity is produced from coal. Renewable sources including hydropower, geothermal, solar, and wind provide less than 7% of our domestic energy. The remaining 8% is supplied by nuclear power. Because of our dependence on fossil fuels, the elaborate infrastructure that has been built to produce, process, and transport these fuels and their products, and the political environment, a transition to other energy sources will not occur before the middle of the 21st century. Moderate prices for fossil fuels will also slow transition to the next energy source. Demand for fossil fuels, especially natural gas, will continue to increase. Hydrogen is currently the dominant candidate for the first carbon-free fuel and many are working on the transition to hydrogen-based fuel technologies. Based on the existing infrastructure, costs, and availability, natural gas is a logical initial source for hydrogen. In the transition to an affordable, efficient, reliable, environmentally more benign, nearly carbon-free energy economy, substantial demand will continue to exist for crude oil, natural gas, and coal, even as they are phased out.