This article needs to be updated.March 2021)(
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).
Electricity is not freely available in nature, so it must be "produced" (that is, 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.
The fundamental principles of electricity generation were discovered in the 1820s and early 1830s by British scientist Michael Faraday. His method, still used today, is for electricity to be generated by the movement of a loop of wire, or Faraday disc, between the poles of a magnet. Central power stations became economically practical with the development of alternating current (AC) power transmission, using power transformers to transmit power at high voltage and with low loss.
Commercial electricity production started in 1873[ citation needed ] with the coupling of the dynamo to the hydraulic turbine. The mechanical production of electric power began the Second Industrial Revolution and made possible several inventions using electricity, with the major contributors being Thomas Alva Edison and Nikola Tesla. Previously the only way to produce electricity was by chemical reactions or using battery cells, and the only practical use of electricity was for the telegraph.
Electricity generation at central power stations started in 1882, when a steam engine driving a dynamo at Pearl Street Station produced a DC current that powered public lighting on Pearl Street, New York. The new technology was quickly adopted by many cities around the world, which adapted their gas-fueled street lights to electric power. Soon after electric lights would be used in public buildings, in businesses, and to power public transport, such as trams and trains.
The first power plants used water power or coal.Today a variety of energy sources are used, such as coal, nuclear, natural gas, hydroelectric, wind, and oil, as well as solar energy, tidal power, and geothermal sources.
Several fundamental methods exist to convert other forms of energy into electrical energy. Utility-scale generation is achieved by rotating electric generators or by photovoltaic systems. A small proportion of electric power distributed by utilities is provided by batteries. Other forms of electricity generation used in niche applications include the triboelectric effect, the piezoelectric effect, the thermoelectric effect, and betavoltaics.
Electric generators transform kinetic energy into electricity. This is the most used form for generating electricity and is based on Faraday's law. It can be seen experimentally by rotating a magnet within closed loops of conducting material (e.g. copper wire). Almost all commercial electrical generation is done using electromagnetic induction, in which mechanical energy forces a generator to rotate:
Electrochemistry is the direct transformation of chemical energy into electricity, as in a battery. Electrochemical electricity generation is important in portable and mobile applications. Currently, most electrochemical power comes from batteries.Primary cells, such as the common zinc–carbon batteries, act as power sources directly, but secondary cells (i.e. rechargeable batteries) are used for storage systems rather than primary generation systems. Open electrochemical systems, known as fuel cells, can be used to extract power either from natural fuels or from synthesized fuels. Osmotic power is a possibility at places where salt and fresh water merge.
The photovoltaic effect is the transformation of light into electrical energy, as in solar cells. Photovoltaic panels convert sunlight directly to DC electricity. Power inverters can then convert that to AC electricity if needed. Although sunlight is free and abundant, solar power electricity is still usually more expensive to produce than large-scale mechanically generated power due to the cost of the panels. Low-efficiency silicon solar cells have been decreasing in cost and multijunction cells with close to 30% conversion efficiency are now commercially available. Over 40% efficiency has been demonstrated in experimental systems.Until recently, photovoltaics were most commonly used in remote sites where there is no access to a commercial power grid, or as a supplemental electricity source for individual homes and businesses. Recent advances in manufacturing efficiency and photovoltaic technology, combined with subsidies driven by environmental concerns, have dramatically accelerated the deployment of solar panels. Installed capacity is growing by 40% per year led by increases in Germany, Japan, United States, China, and India.
The selection of electricity production modes and their economic viability varies in accordance with demand and region. The economics vary considerably around the world, resulting in widespread residential selling prices, e.g. the price in Iceland is 5.54 cents per kWh while in some island nations it is 40 cents per kWh. Hydroelectric plants, nuclear power plants, thermal power plants and renewable sources have their own pros and cons, and selection is based upon the local power requirement and the fluctuations in demand. All power grids have varying loads on them but the daily minimum is the base load, often supplied by plants which run continuously. Nuclear, coal, oil, gas and some hydro plants can supply base load. If well construction costs for natural gas are below $10 per MWh, generating electricity from natural gas is cheaper than generating power by burning coal.
Thermal energy may be economical in areas of high industrial density, as the high demand cannot be met by local renewable sources. The effect of localized pollution is also minimized as industries are usually located away from residential areas. These plants can also withstand variation in load and consumption by adding more units or temporarily decreasing the production of some units. Nuclear power plants can produce a huge amount of power from a single unit. However, nuclear disasters have raised concerns over the safety of nuclear power, and the capital cost of nuclear plants is very high. Hydroelectric power plants are located in areas where the potential energy from falling water can be harnessed for moving turbines and the generation of power. It may not be an economically viable single source of production where the ability to store the flow of water is limited and the load varies too much during the annual production cycle.
Due to advancements in technology, and with mass production, renewable sources other than hydroelectricity (solar power, wind energy, tidal power, etc.) experienced decreases in cost of production, and the energy is now in many cases as expensive or less expensive than fossil fuels.Many governments around the world provide subsidies to offset the higher cost of any new power production, and to make the installation of renewable energy systems economically feasible.
Electric generators were known in simple forms from the discovery of electromagnetic induction in the 1830s. In general, some form of prime mover such as an engine or the turbines described above, drives a rotating magnetic field past stationary coils of wire thereby turning mechanical energy into electricity.The only commercial scale electricity production that does not employ a generator is solar PV.
Almost all commercial electrical power on Earth is generated with a turbine, driven by wind, water, steam or burning gas. The turbine drives a generator, thus transforming its mechanical energy into electrical energy by electromagnetic induction. There are many different methods of developing mechanical energy, including heat engines, hydro, wind and tidal power. Most electric generation is driven by heat engines. The combustion of fossil fuels supplies most of the energy to these engines, with a significant fraction from nuclear fission and some from renewable sources. The modern steam turbine (invented by Sir Charles Parsons in 1884) currently generates about 80% of the electric power in the world using a variety of heat sources. Turbine types include:
Although turbines are most common in commercial power generation, smaller generators can be powered by gasoline or diesel engines. These may used for backup generation or as a prime source of power within isolated villages.
This section needs to be updated.March 2015)(
Total worldwide gross production of electricity in 2016 was 25,082 TWh. Sources of electricity were coal and peat 38.3%, natural gas 23.1%, hydroelectric 16.6%, nuclear power 10.4%, oil 3.7%, solar/wind/geothermal/tidal/other 5.6%, biomass and waste 2.3%.
|Average electric power (TWh/year)||8,263||1,111||4,301||2,731||3,288||568||20,261|
|Average electric power (GW)||942.6||126.7||490.7||311.6||375.1||64.8||2311.4|
Total energy consumed at all power plants for the generation of electricity was 51,158 terawatt-hours (4,398,768 kilotonnes of oil equivalent ) which was 36% of the total for primary energy sources (TPES) of 2008. Electricity output (gross) was 20,185 TWh (1,735,579 ktoe), efficiency was 39%, and the balance of 61% was generated heat. A small part, 1,688 TWh (145,141 ktoe) or about 3% of the input total, of the heat was utilized at co-generation heat and power plants. The in-house consumption of electricity and power transmission losses were 3,369 TWh (289,681 ktoe). The amount supplied to the final consumer was 16,809 TWh (1,445,285 ktoe) which was 33% of the total energy consumed at power plants and heat and power co-generation (CHP) plants.
Note that the vertical axes of these two charts are not to the same scale.
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The United States has long been the largest producer and consumer of electricity, with a global share in 2005 of at least 25%, followed by China, Japan, Russia, and India. In 2011, China overtook the United States to become the largest producer of electricity.
This section needs to be updated.December 2019)(
Data source of values (electric power generated) is IEA/OECD.Listed countries are top 20 by population or top 20 by GDP (PPP) and Saudi Arabia based on CIA World Factbook 2009.
|Country's electricity sector||Fossil Fuel||Nuclear||rank||Renewable||Bio|
Solar PV* is Photovoltaics Bio other* = 198 TWh (Biomass) + 69 TWh (Waste) + 4 TWh (other)
Variations between countries generating electrical power affect concerns about the environment. In France only 10% of electricity is generated from fossil fuels, the US is higher at 70% and China is at 80%.The cleanliness of electricity depends on its source. Most scientists agree that emissions of pollutants and greenhouse gases from fossil fuel-based electricity generation account for a significant portion of world greenhouse gas emissions; in the United States, electricity generation accounts for nearly 40% of emissions, the largest of any source. Transportation emissions are close behind, contributing about one-third of U.S. production of carbon dioxide. In the United States, fossil fuel combustion for electric power generation is responsible for 65% of all emissions of sulfur dioxide, the main component of acid rain. Electricity generation is the fourth highest combined source of NOx, carbon monoxide, and particulate matter in the US. In July 2011, the UK parliament tabled a motion that "levels of (carbon) emissions from nuclear power were approximately three times lower per kilowatt hour than those of solar, four times lower than clean coal and 36 times lower than conventional coal".
|Technology||Description||50th percentile |
|Nuclear||various generation II reactor types||16|
|Solar thermal||parabolic trough||22|
|Geothermal||hot dry rock||45|
|Solar PV||Polycrystalline silicon||46|
|Natural gas||various combined cycle turbines without scrubbing||469|
|Coal||various generator types without scrubbing||1001|
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.
Distributed generation, also distributed energy, on-site generation (OSG), or district/decentralized energy, is electrical generation and storage performed by a variety of small, grid-connected or distribution system-connected devices referred to as distributed energy resources (DER).
Electric power systems consist of generation plants of different energy sources, transmission networks, and distribution lines. Each of these components can have environmental impacts at multiple stages of their development and use including in their construction, during the generation of electricity, and in their decommissioning and disposal. We can split these impacts into operational impacts and construction impacts. This page looks exclusively at the operational environmental impact of electricity generation. The page is organized by energy source and includes impacts such as water usage, emissions, local pollution, and wildlife displacement.
Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time. Trigeneration or combined cooling, heat and power (CCHP) refers to the simultaneous generation of electricity and useful heating and cooling from the combustion of a fuel or a solar heat collector. The terms cogeneration and trigeneration can also be applied to the power systems simultaneously generating electricity, heat, and industrial chemicals.
A fossil fuel power station is a thermal power station which burns a fossil fuel, such as coal or natural gas, to produce electricity. Fossil fuel power stations have machinery to convert the heat energy of combustion into mechanical energy, which then operates an electrical generator. The prime mover may be a steam turbine, a gas turbine or, in small plants, a reciprocating gas engine. All plants use the energy extracted from expanding gas, either steam or combustion gases. Although different energy conversion methods exist, all thermal power station conversion methods have efficiency limited by the Carnot efficiency and therefore produce waste heat.
Energy use in the United Kingdom stood at 2,249 TWh in 2014. This equates to energy consumption per capita of 34.82 MWh compared to a 2010 world average of 21.54 MWh. Demand for electricity in 2014 was 34.42GW on average coming from a total electricity generation of 335.0TWh.
Electric energy consumption is the form of energy consumption that uses electric energy. Electric energy consumption is the actual energy demand made on existing electricity supply.
World energy consumption is the total energy produced and used by humans. Typically measured per year, it involves all energy harnessed from every energy source applied towards activity across all industrial and technological sectors, in every country. It does not include energy from food. World energy consumption has implications for the socio-economic-political sphere.
Renewable energy in Germany is mainly based on wind, solar and biomass. Germany had the world's largest photovoltaic installed capacity until 2014, and as of 2020 it has 49 GW. It is also the world's third country by installed wind power capacity, at 59 GW in 2018, and second for offshore wind, with over 4 GW. Germany has been called "the world's first major renewable energy economy".
A gas-fired power plant or gas-fired power station or natural gas power plant is a thermal power station which burns natural gas to generate electricity. Natural gas power stations generates almost a quarter of world electricity and a significant part of global greenhouse gas emissions and thus global warming. However they can provide seasonal dispatchable generation to balance variable renewable energy where hydropower or interconnectors are not available.
Solar power is the conversion of energy from sunlight into electricity, either directly using photovoltaics (PV), indirectly using concentrated solar power, or a combination. Concentrated solar power systems use lenses or mirrors and solar tracking systems to focus a large area of sunlight into a small beam. Photovoltaic cells convert light into an electric current using the photovoltaic effect.
Low-carbon power is electricity produced with substantially lower greenhouse gas emissions than conventional fossil fuel power generation. The energy transition to low-carbon power is one of the most important actions required to limit climate change. Power sector emissions may have peaked in 2018.
Energy in Germany is sourced predominantly by fossil fuels, followed by wind, nuclear power, solar, biomass and hydro.
Energy technology is an interdisciplinary engineering science having to do with the efficient, safe, environmentally friendly, and economical extraction, conversion, transportation, storage, and use of energy, targeted towards yielding high efficiency whilst skirting side effects on humans, nature, and the environment.
Different methods of electricity generation can incur significantly different costs, and these costs can occur at significantly different times relative to when the power is used. The costs include the initial capital, and the costs of continuous operation, fuel, and maintenance as well as the costs of de-commissioning and remediating any environmental damage. Calculations of these costs can be made at the point of connection to a load or to the electricity grid, so that they may or may not include the transmission costs.
Energy in Malta describes energy production, consumption and import in Malta. Malta has no domestic resource of fossil fuels and no gas distribution network, and relies overwhelmingly on imports of fossil fuels and electricity to cover its energy needs. Since 2015, the Malta–Sicily interconnector allows Malta to be connected to the European power grid and import a significant share of its electricity.
The United Kingdom has a National Grid that covers most of mainland Great Britain and several of the surrounding islands, as well as some connectivity to other countries. In 2020 the electricity sector's grid supply came from 55% low-carbon power, 36.1% fossil fuelled power, and 8.4% imports. Renewable power is showing strong growth, while fossil fuel generator use in general and coal use in particular is shrinking, with historically dominant coal generators now mainly being run in winter due to pollution and costs, and contributed just 1.6% of the supply in 2020.
Worldwide energy supply is the global production and preparation of fuel, generation of electricity, and energy transport. Energy supply is a vast industry.
Centralised generation refers the common process of electricity generation through large-scale centralised facilities, through Transmission lines to consumer. These facilities are usually located far away from consumers and distribute the electricity through high voltage transmission lines to a substation where it is then distributed to consumers. The basic concept being that incredibly large stations create electricity for a large group of people. The Vast majority of electricity used in Australia as well as the United States is created from Centralised Generation. Most Centralised Power Generation comes from large power plants run by fossil fuels such as coal or natural gas. Nuclear or large hydroelectricity plants are also commonly used. Many disagree with the processes of Centralised Generation as it often relies on electrical generation through processes of the combustion of fossil fuels, which are bad for the environment. However unsustainable the current system is, it is by far the most widely used, reliable and efficient system that is currently in use.