Like water, food, and air, electrical energy has become an integral part of daily personal and business lives. People have become so accustomed to flicking a switch and having instant light, action, or communication that little thought is given to the process that produces this electrical energy or how it gets to where it is used. It is unique in that practically all that is produced is not stored but used instantly in the quantities that are needed. For alternatives to electrical energy, one must go back to the days of gas lamps, oil lamps, candles, and steam- or water-powered mechanical devices—and work days or leisure time that was limited to daylight hours for the most part.