Electric generator in the context of Electrical power

A steam turbine or steam turbine engine is a machine or heat engine that extracts thermal energy from pressurized steam and uses it to do mechanical work utilising a rotating output shaft. Its modern manifestation was invented by Sir Charles Parsons in 1884. It revolutionized marine propulsion and navigation to a significant extent. Fabrication of a modern steam turbine involves advanced metalwork to form high-grade steel alloys into precision parts using technologies that first became available in the 20th century; continued advances in durability and efficiency of steam turbines remains central to the energy economics of the 21st century. The largest steam turbine ever built is the 1,770 MW Arabelle steam turbine built by Arabelle Solutions (previously GE Steam Power), two units of which will be installed at Hinkley Point C Nuclear Power Station, England.

The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency from the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible expansion process. Because the turbine generates rotary motion, it can be coupled to a generator to harness its motion into electricity. Such turbogenerators are the core of thermal power stations which can be fueled by fossil fuels, nuclear fuels, geothermal, or solar energy. About 42% of all electricity generation in the United States in 2022 was by the use of steam turbines. Technical challenges include rotor imbalance, vibration, bearing wear, and uneven expansion (various forms of thermal shock).

Electricity generation is the process of generating electric power from sources of primary energy. For utilities in the electric power industry, it is the stage prior to its delivery (transmission, distribution, etc.) to end users or its storage, using for example, the pumped-storage method.

Consumable electricity is not freely available in nature, so it must be "produced", transforming other forms of energy to electricity. Production is carried out in power stations, also called "power plants". Electricity is most often generated at a power plant by electromechanical generators, primarily driven by heat engines fueled by combustion or nuclear fission, but also by other means such as the kinetic energy of flowing water and wind. Other energy sources include solar photovoltaics and geothermal power. There are exotic and speculative methods to recover energy, such as proposed fusion reactor designs which aim to directly extract energy from intense magnetic fields generated by fast-moving charged particles generated by the fusion reaction (see magnetohydrodynamics).

A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid.

Many power stations contain one or more generators, rotating machine that converts mechanical power into three-phase electric power. The relative motion between a magnetic field and a conductor creates an electric current.

Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to move a positive test charge from the first point to the second point. In the International System of Units (SI), the derived unit for voltage is the volt (V).

The voltage between points can be caused by the build-up of electric charge (e.g., a capacitor), and from an electromotive force (e.g., electromagnetic induction in a generator). On a macroscopic scale, a potential difference can be caused by electrochemical processes (e.g., cells and batteries), the pressure-induced piezoelectric effect, photovoltaic effect, and the thermoelectric effect. Since it is the difference in electric potential, it is a physical scalar quantity.

A loudspeaker (commonly referred to as a speaker or, more fully, a speaker system) is a combination of one or more speaker drivers, an enclosure, and electrical connections (possibly including a crossover network). The speaker driver is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound.

The driver is a linear motor connected to a diaphragm, which transmits the motor's movement to produce sound by moving air. An audio signal, typically originating from a microphone, recording, or radio broadcast, is electronically amplified to a power level sufficient to drive the motor, reproducing the sound corresponding to the original unamplified signal. This process functions as the inverse of a microphone. In fact, the dynamic speaker driver—the most common type—shares the same basic configuration as a dynamic microphone, which operates in reverse as a generator.

An electric power system is a network of electrical components deployed to supply, transfer, and use electric power. An example of a power system is the electrical grid that provides power to homes and industries within an extended area. The electrical grid can be broadly divided into the generators that supply the power, the transmission system that carries the power from the generating centers to the load centers, and the distribution system that feeds the power to nearby homes and industries.

Smaller power systems are also found in industry, hospitals, commercial buildings, and homes. A single line diagram helps to represent this whole system. The majority of these systems rely upon three-phase AC power—the standard for large-scale power transmission and distribution across the modern world. Specialized power systems that do not always rely upon three-phase AC power are found in aircraft, electric rail systems, ocean liners, submarines, and automobiles.

A turbine (/ˈtɜːrbaɪn/ or /ˈtɜːrbɪn/) (from the Greek τύρβη, tyrbē, or Latin turbo, meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced can be used for generating electrical power when combined with a generator. A turbine is a turbomachine with at least one moving part called a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades so that they move and impart rotational energy to the rotor.

Gas, steam, and water turbines have a casing around the blades that contains and controls the working fluid. Modern steam turbines frequently employ both reaction and impulse in the same unit, typically varying the degree of reaction and impulse from the blade root to its periphery.

A turbo generator is an electric generator connected to the shaft of a turbine (water, steam, or gas) for the generation of electric power. Large steam-powered turbo generators provide the majority of the world's electricity and are also used by steam-powered turbo-electric and gas-turbine-electric powered ships.

Small turbo-generators driven by gas turbines are often used as auxiliary power units (APU, mainly for aircraft).

A thermal power station, also known as a thermal power plant, is a type of power station in which the heat energy generated from various fuel sources (e.g., coal, natural gas, nuclear fuel, etc.) is converted to electrical energy. The heat from the source is converted into mechanical energy using a thermodynamic power cycle (such as a Diesel cycle, Rankine cycle, Brayton cycle, etc.). The most common cycle involves a working fluid (often water) heated and boiled under high pressure in a pressure vessel to produce high-pressure steam. This high pressure-steam is then directed to a turbine, where it rotates the turbine's blades. The rotating turbine is mechanically connected to an electric generator which converts rotary motion into electricity. Fuels such as natural gas or oil can also be burnt directly in gas turbines (internal combustion), skipping the steam generation step. These plants can be of the open cycle or the more efficient combined cycle type.

The majority of the world's thermal power stations are driven by steam turbines, gas turbines, or a combination of the two. The efficiency of a thermal power station is determined by how effectively it converts heat energy into electrical energy, specifically the ratio of saleable electricity to the heating value of the fuel used. Different thermodynamic cycles have varying efficiencies, with the Rankine cycle generally being more efficient than the Otto or Diesel cycles. In the Rankine cycle, the low-pressure exhaust from the turbine enters a steam condenser where it is cooled to produce hot condensate which is recycled to the heating process to generate even more high pressure steam.

A nuclear power plant (NPP), also known as a nuclear power station (NPS), nuclear generating station (NGS) or atomic power station (APS) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a generator that produces electricity. As of October 2025, the International Atomic Energy Agency reported that there were 416 nuclear power reactors in operation in 31 countries around the world, and 62 nuclear power reactors under construction.

Most nuclear power plants use thermal reactors with enriched uranium in a once-through fuel cycle. Fuel is removed when the percentage of neutron absorbing atoms becomes so large that a chain reaction can no longer be sustained, typically three years. It is then cooled for several years in on-site spent fuel pools before being transferred to long-term storage. The spent fuel, though low in volume, is high-level radioactive waste. While its radioactivity decreases exponentially, it must be isolated from the biosphere for hundreds of thousands of years, though newer technologies (like fast reactors) have the potential to significantly reduce this. Because the spent fuel is still mostly fissionable material, some countries (e.g. France and Russia) reprocess their spent fuel by extracting fissile and fertile elements for fabrication into new fuel, although this process is more expensive than producing new fuel from mined uranium. All reactors breed some plutonium-239, which is found in the spent fuel, and because Pu-239 is the preferred material for nuclear weapons, reprocessing is seen as a weapon proliferation risk.

Autogas is liquefied petroleum gas (LPG) used as a fuel in internal combustion engines of vehicles as well as in stationary applications such as generators. It is a mixture of propane and butane.

Autogas is widely used as a "green" fuel, as its use reduces CO₂ exhaust emissions by around 15% compared to petrol. One litre of petrol produces 2.3 kg of CO₂ when burnt, whereas the equivalent amount of autogas (1.33 litres due to the lower density of autogas) produces 2 kg of CO₂ when burnt. CO emissions are 30% lower compared to petrol, and NO_x is reduced by 50%. It has an octane rating (MON/RON) that is between 90 and 110 and an energy content (higher heating value—HHV) that is between 25.5 megajoules per litre (for pure propane) and 28.7 megajoules per litre (for pure butane) depending upon the actual fuel composition.

An electricity market is a system that enables the exchange of electrical energy through an electrical grid. Historically, electricity has been primarily sold by companies that operate electric generators, purchased by electricity retailers, and sold to customers.

The electric power industry began in the late 19th and early 20th centuries in the United States and United Kingdom. Throughout the 20th century, and up to the present, many countries have made changes to their system of supplying and/or purchasing electricity. Change has been driven by many factors, ranging from technological advances (on both the supply and demand side) to politics and ideology.

Electric power is the rate of transfer of electrical energy within a circuit. Its SI unit is the watt, the general unit of power, defined as one joule per second. Standard prefixes apply to watts as with other SI units: thousands, millions and billions of watts are called kilowatts, megawatts and gigawatts respectively.

In common parlance, electric power is the production and delivery of electrical energy, an essential public utility in much of the world. Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries. It is usually supplied to businesses and homes (as domestic mains electricity) by the electric power industry through an electrical grid.

Electromechanics combine processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focus on the interaction of electrical and mechanical systems as a whole and how the two systems interact with each other. This process is especially prominent in systems such as those of DC or AC rotating electrical machines which can be designed and operated to generate power from a mechanical process (generator) or used to power a mechanical effect (motor). Electrical engineering in this context also encompasses electronics engineering.

Electromechanical devices are ones which have both electrical and mechanical processes. Strictly speaking, a manually operated switch is an electromechanical component due to the mechanical movement causing an electrical output. Though this is true, the term is usually understood to refer to devices which involve an electrical signal to create mechanical movement, or vice versa mechanical movement to create an electric signal. Often involving electromagnetic principles such as in relays, which allow a voltage or current to control another, usually isolated circuit voltage or current by mechanically switching sets of contacts, and solenoids, by which a voltage can actuate a moving linkage as in solenoid valves.

Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, maximum effect or gross capacity, is the intended full-load sustained output of a facility such as a power station, electric generator, a chemical plant, fuel plant, mine, metal refinery, and many others. Nameplate capacity is the theoretical output registered with authorities for classifying the unit. For intermittent power sources, such as wind and solar, nameplate power is the source's output under ideal conditions, such as maximum usable wind or high sun on a clear summer day.

Capacity factor measures the ratio of actual output over an extended period to nameplate capacity. Power plants with an output consistently near their nameplate capacity have a high capacity factor.