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Power Plants

Electricity is of vital importance to societies around the globe. Modern society has come to depend on reliable electricity as an essential resource for national security, health and welfare, communications, finance, transportation, food and water supply, heating, cooling, lighting, computers, electronics, commercial enterprise, and even entertainment and leisure [1]. Industries, commerce, households, transportation systems, and other sectors would simply cease to exist if they were cut from their electric supply. Today, our economy relies more than ever on reliable, affordable supplies of electricity [2]. Lack of electricity causes not only inconvenience, but also economic loss due to reduced industrial production [3].

As a most basic definition, electricity is a form of energy characterized by the presence and motion of charged particles generated by friction, induction, or chemical change. Electricity is a secondary energy source which means that we get it from the conversion of other sources of energy [4]. This conversion typically takes place at an electric power plant.

There are a number of ways to produce electricity; the most common commercial way is through the use of a synchronous generator driven by a rotating turbine. The combination is called a turbine-generator [5]. The most common method for spinning the turbine-generator is by harnessing the power of steam. Water is converted to steam by burning a fuel in a boiler to heat the water [5]. Steam can be created from burning coal, oil, or natural gas, from a nuclear reactor, or from harnessing the heat of the earth (geothermal) [6, 7]. The generator can also be manually spun through the harnessing of water in a hydroelectric dam, waves or tides, or wind with a wind turbine. Additionally, diesel oil can be burned in generating units with internal-combustion engines to produce electricity. The combustion occurs inside cylinders of the engine, which is connected to the shaft of the generator. The mechanical energy provided from the engine drives the generator to produce energy [7]. Lastly, electricity can be created directly with solar photovoltaic cells, eliminating the need for a spinning generator. It is important to realize that the energy source used to make electricity may be renewable or non-renewable, but electricity itself is neither renewable or non-renewable [4].

There are more than 5,200 power producing entities in the Unites States falling into a number of specific categories. Of this, there are more than 3,100 traditional electric utilities in the US which are responsible for ensuring an adequate and reliable source of electricity to all consumers [3]. These utilities include investor-owned, publicly owned, cooperative, and federal utilities. Power marketers are also considered electric utilities – these entities buy and sell electricity, but usually do not own or operate generation, transmission, or distribution facilities. Utilities are regulated by local, state, and federal authorities [3]. The remaining entities are non-utility power producers; there are more than 2,100 non-utility power producers in the US, which include cogeneration facilities engaged in business activities other than the sale of electricity, independent power producers that produce and sell electricity on the wholesale market at non-regulated rates, and exempt wholesale generators under the Energy Policy Act [3].

Power plants represent only a single component of the electricity grid, which is made up of countless other components. These components together form the US electric system – which is the largest in the world, with over twice the generating capacity of any other country [8]. The North American electricity system is one of the great engineering achievements of the past 100 years. This electricity infrastructure represents more than $1 trillion dollars in asset value, more than 200,000 miles of transmission lines operating at 230,000 volts and greater, 950,000 megawatts of generating capability, and nearly 3,500 utility organizations serving well over 100 million customers and 283 million people [1].

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