Widespread use of electric power has been one of the greatest sources of social change in the 20th century. It influenced the course of industrialization by allowing us to build factories farther from the sources of power, making large-scale manufacturing possible. It changed the face of cities in terms of growth and population, helped farmers increase production through labor-saving machinery, and contributed to a more highly educated populace, liberated from the drudgery of manual chores and labor.
Mass electrification in the United States required the expertise of thousands of engineers. Among them were pioneers who recognized that the natural resources of fossil fuels, water, and sunlight could be turned into electric power; and others who learned how to build the machinery to convert those resources to electric power. Still others learned how to transmit that power over wires and into our houses, barns, offices and factories. Their efforts allow us to awaken to an electric alarm, turn on the lights, toast bread, and use any number of electrical appliances or devices to prepare for the day.
In contrast, the average person in 1900 awoke to a hand-wound clock, often well before sunrise. In an era of kerosene lamps and lanterns, there was no electric light switch; in an era of outhouses and manual water pumps, no tap to turn for running water. There was no radio or TV for local or world news, and preparing for the day took a long time — getting coal or wood for the kitchen stove, using hand-tools to prepare food. Farmers had no electric motors or machinery to milk cows or process grain. Household chores were grueling: scrubbing laundry on washboards, heating heavy irons on the stove, or hauling cumbersome rugs to a clothesline to be pounded with a carpet beater.
At the start of the 20th Century, electric power was young but growing rapidly. Thomas Edison's work had led to the first commercial power plant for incandescent lighting and power in 1882. However, Edison's system used direct current (DC), which could only be profitably distributed in a limited area around the generating station. The work of engineers such as Nikola Tesla and Charles Steinmetz led to the successful commercialization of alternating current (AC), which enabled transmission of high-voltage power over large distances.
Prime movers in power stations evolved from water wheels to dams with a variety of turbines: reaction and hydraulic, fixed and variable blade, turbines that could be reversed to pump water into elevated storage wells, then reversed back to generate power. Each design innovation met the burgeoning needs of an increasingly industrial society.
Benchmarks along the way included the steam turbine generator in 1903, pioneered by Charles Curtis. It generated 5,000 kilowatts and was then the most powerful plant in the world. It marked a transition to turbine generators that required one-tenth the space and weighed one-eighth as much as reciprocating engines of comparable output. The next breakthrough was the world's first high-pressure steam plant, which further increased efficiency and brought substantial savings in fuel. The Edgar Station in Boston (1925) became a model for high-pressure power plants worldwide.
Adapting fuels to power generation was, and still is, an ongoing process. One early milestone was the use of pulverized coal, demonstrated in 1918 at the Oneida Street plant in Milwaukee. As steam pressures inched up in the increasing quest for more power, new materials such as chrome-molybdenum steel offered superior heat resistance in turbines.
But even as power plants and fuel resources became more developed, bringing electricity to the rural world was a low priority for power companies. The monetary return was minimal due to the small numbers of customers per mile versus the high cost of constructing a distribution line. Of the potential 5 million customers early in the century, only some 247,000 had electricity.
In spite of growing awareness that the country's economic development depended on a rural population with the same opportunities and amenities as people in the cities, a major push for this did not happen until the Depression. In 1935 the Rural Electric Administration (REA) was established, and President Roosevelt chose Morris Llewellyn Cooke — an engineer — to head it. He was charged with the following task: Electrify the majority of the continent. Quickly.
To make electricity affordable, Cooke instituted innovations that included standardized designs for distribution lines, mass production and construction techniques, system protection, and wide area distributed power planning. It was a remarkable undertaking. Construction costs plummeted from $2,000 per line mile at the beginning of the project to less than $600 by 1939.
The impact of electric power on agriculture became as significant to the farmer as steam or gasoline had previously. Electric motors drove barn machinery, grain crushers, and water pumps. Eventually, the electric motor began to replace the mobile steam engine in equipment for threshing, winnowing, and other crop-processing.
Early public works projects built during the Depression are still major providers of electricity today. The hydroelectric generators of the Hoover Dam, built between 1932 and 1935, supply nearly 1.5 million kilowatts-hours of electrical power per year to people in Arizona, Nevada, and southern California. In 1933, the Tennessee Valley Authority (TVA) was launched to bring power and flood relief to the Tennessee River basin. It currently operates numerous dams, 11 large coal-burning steam plants, and two nuclear plants in Alabama and Tennessee. They produce more than 125 billion kilowatt-hours of electricity annually — almost 90 times that generated in the same region in 1933.
Since the early days of power generation and distribution, the use of various fuel sources has resulted in environmental consequences. As knowledge and experience with fuel sources has grown, new technologies have emerged to address these problems. The growing field of environmental engineering focuses on techniques for measuring pollutants, the development of clean fuel technologies, and other initiatives.
The electric power grid system continues to develop with a movement to interconnect grids into huge national or international networks. For example, in the United States, the whole country was linked into two giant grid systems by the 1990s, one serving each half of the country. This allows power produced in one state to be used thousands of miles away. Practical transmission voltages have increased steadily from 220 volts in the 1880s to 765,000 volts in 1999. Indeed, transmission techniques have now come full circle, with a return to DC transmission at high voltage. Made possible with semiconductor switches, the use of long-range DC transmission is just beginning — one of many technologies that hold promise in bringing further advantages in economy and reliability.
