ABSTRACT
Energy is used in different forms: airplanes and automobiles use liquid hydrocarbon fuels; electric power plants convert the energy of coal, natural gas, nuclear, and flowing water into electricity; households use electricity and natural gas for domestic comfort with heating and air-conditioning, communications, entertainment, and the preparation of meals; factories use natural gas, petroleum, and coal for processing materials and manufacturing; and commercial buildings use natural gas, petroleum products, and electricity for heating and air-conditioning. Because most functions in our society are based on the use of specific forms of energy, elaborate networks for the supply of the needed energy forms have been developed in the last two centuries. Electricity is fed into our communities by the transmission lines of the electric grid at very high voltage. Natural gas enters our dwellings by a complex system of underground pipelines, which often transcend national boundaries. Large tanker trucks supply the gasoline stations with petroleum products. Tanker ships crisscross the oceans daily to bring petroleum to the refineries that, in turn, supply the tanker trucks and the gasoline stations. The complex and ubiquitous energy network feeds the national economies and sustains the modern human society.
