Environmental Engineering Reference
In-Depth Information
4
CHAPTER
Electrical Energy Generation,
Transmission, and Storage
4.1
INTRODUCTION
Prior to the industrial revolution, human and animal power had provided the bulk of the mechanical
work needed in an agricultural society to provide food, clothing, and shelter for human settlements.
Through invention and technological development, wind, tidal, and river flows provided mechanical
power for milling of grain, sawing of timber, and ocean transportation of goods. But the invention
of the steam engine in the early years of the industrial revolution greatly expanded the amount
of mechanical power available in industrializing countries for the manufacture of goods and the
transportation of people and freight, giving rise to economic growth. By the late nineteenth century
the forms of mechanical power generation had evolved to include the steam turbine and gasoline
and diesel engines and their uses in ocean and land vehicles. By that time the dominant fuels
that produced mechanical power were coal and oil rather than wood. Although human and animal
power, as well as the renewable power of wind and stream, were still significant at the dawn of
the twentieth century, fossil-fueled mechanical engines were clearly the major and rapidly growing
source of industrial energy.
A technological development that greatly augmented the usefulness of mechanical power in
manufacturing and, eventually, commercial and residential settings was the nineteenth-century
invention of the electric generator and motor that converts mechanical and electrical power from
one form to the other with little loss of energy. Unlike mechanical power, which is generated from
fossil fuel at the site of power use, as in a manufacturing plant, railroad locomotive, or steamship,
electric power generation made possible the transmission of electrical power from a central location
to distant consumers via electric transmission lines, which greatly increased the usefulness of the
electrical form of work. Together with the end-use inventions that make electrical power so useful,
such as the electric light and electric communication devices, the production of electric power has
grown so that it constitutes nearly one-third of energy use in current industrialized societies.
Today in the United States, most electric power is generated in large power plants where fossil
or nuclear fuel provides the heat needed to generate mechanical work in a steam cycle, with the
mechanical power being converted to electrical power in the electric generator, or alternator, as
60-cycle synchronous alternating current (AC) electricity.
1
In transmitting the power to distant
1
Electric utility plants are interconnected with each other by transmission lines so that electric power may
be reliably supplied to all customers. This requires synchronization of the generators and standardization of
voltages among participating plants. For a description of these plants, see Chapters 5 and 6.
69
