A power plant is a type of industrial facility that produces electricity using primary energy. Most power plants rely on one or more generators to convert mechanical energy into electrical energy in order to offer electricity to the electrical grid for societal requirements. Some power plants also produce heat and/or steam which are used directly or indirectly to make other products such as paper, steel, and concrete.
The first electric lights were powered by coal-fired generators, and modern power plants still usually include some form of internal combustion engine or motors to run their generators.
Electricity is the flow of electrons through a conductor such as a copper wire. Electricity is generated by any number of different methods, but it must be able to turn a motor or another device capable of generating electricity when given the right kind of input. Mechanical energy, such as that found in the wind or water flowing around a turbine blade, can be converted into electrical energy with little loss of speed or strength. This is why turbines work well for generating electricity.
Mechanical energy can be derived from many sources including water waves, wind, explosions, solar rays, and human or animal power. Human power is used mainly for irrigation purposes while animal power is used mainly for traction applications.
A power plant or power station is where energy is produced (using solar, wind, coal, natural gas, or nuclear power). As another commenter pointed out, these phrases may be used interchangeably. A power station is just a specific type of power plant; it can be thermal (such as a coal-fired power plant) or non-thermal (such as a wind turbine).
In general usage, a power plant produces electricity for sale to others, while a power station supplies electricity to a network for distribution and consumption by others. The former is usually located away from use its output, whereas the latter's location near users allows it to more directly benefit from fluctuations in demand across time zones or on different days of the week.
Some large power plants are able to generate electricity at such a high rate that they can supply regions or nations with all their required capacity. These are often called "centralized power plants". Smaller scale production of electricity using solar cells or other methods is done by individuals, businesses, and organizations who are called "distributed generation" providers. Because distributed generation does not need to meet the demands of many people or companies, it can be run efficiently without being connected to a public utility system. It can also be useful for reducing carbon emissions since it does not require burning fossil fuels to produce electricity.
At a power plant, electricity is often created by electromechanical generators, which are generally powered by heat engines fueled by combustion or nuclear fission, but also by other methods such as the kinetic energy of flowing water and wind. Solar photovoltaics and geothermal power are two alternative energy sources. In solar photovoltaic systems, sunlight converts silicon cells into electricity.
Electrical power generation uses an electrical generator to convert mechanical movement (such as that from a motor) into electricity. This can be done directly using electromagnetic induction by having a current-carrying conductor attached to a rotating body, which when moved through a stationary one, causes electrons to be ejected from the metal of the conductor. Alternatively, electric power can be generated by electrochemical means, using a battery to store energy released during braking or during times of peak demand. Electricity is then produced when more energy is needed at some point in time. Batteries can be charged using many different techniques including direct connection to AC power outlets, charging with electricity from solar panels or fuel cells, and magnetic charging using inductors.
The first electric generators were based on dynamos, which used the motion of a armature to create a magnetic field around a coil of wire. This could be done manually with a crank, or automatically using an electric motor. Modern power plants usually have large electric motors that drive steam turbines or gas turbines to create a flow of hot air or gas which powers these generators.
Power plant engineering, often known as power station engineering, is a branch of power engineering that defines itself as "the engineering and technology necessary for the generation of central station electric power." The field is focused on the generation of electricity for companies and communities, not on the creation of residential power. However many large scale commercial power plants also produce heat and cold for distribution.
The term "power plant" can be used to describe any one of several types of power generators, but it usually refers to a hydroelectric generator or a nuclear reactor cooled by water. It may also refer to a gas-turbine generator or an oil-fired generator. All types of power plants require skilled engineers to design them properly. Other disciplines may be involved in their construction, including mining, metalworking, woodworking, plumbing, electrical work, and so on.
A power plant is the largest single consumer of energy in the world. It is estimated that it takes about 2% of the world's total renewable energy production to run all the power plants in the world. This amounts to about 20 billion barrels of oil per year, which is almost as much as the entire United States consumption. Power plants also emit a number of other pollutants such as carbon dioxide, nitrogen oxides, and sulfur dioxide. These emissions contribute to global warming.
The majority of the energy generated in the United States and across the world is generated by electric power plants that employ turbines to power generators. The generator, in turn, turns the rotor's mechanical (kinetic) energy to electrical energy. Electric power is transmitted to homes and businesses over high-voltage transmission lines or distributed directly to consumers' premises through a network of distribution cables.
Turbines are also used in generating stations as part of renewable energy projects to produce electricity from natural sources such as wind and water waves. As opposed to conventional turbine designs which transform rotational kinetic energy to acoustic energy via spinning disks or blades, wave driven turbines use the pressure fluctuations caused by waves moving towards the shore or ocean floor to rotate a shaft, which in turn drives a generator for electricity production. Wave driven turbines can be horizontal axis or vertical axis designs. Horizontal-axis turbines feature a rotating hub with arms extending outwards, which rotate when exposed to the force of the water. Vertical-axis turbines have a vertically rotating shaft with arms extending outwards, which rotate when exposed to the force of the water.
Electricity generation from wind requires large-scale wind farms consisting of hundreds or even thousands of individual wind turbines. Electricity from water waves is generated from beaches around the world; it is not feasible to build such large structures out in the ocean. However, small-scale wave driven generators are available for residential and commercial use.