Electricity generation

Electricity generation

Overview
Electricity generation is the process of generating electric energy from other forms of energy
Forms of energy
In the context of physical sciences, several forms of energy have been defined. These include:These energies may be divided into two main groups; kinetic energy and potential energy. Other familiar types of energy are a varying mix of both potential and kinetic energy...

.

The fundamental principles of electricity generation were discovered during the 1820s and early 1830s by the British scientist Michael Faraday
Michael Faraday
Michael Faraday, FRS was an English chemist and physicist who contributed to the fields of electromagnetism and electrochemistry....

. His basic method is still used today: electricity is generated by the movement of a loop of wire, or disc of copper between the poles of a magnet
Magnet
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets.A permanent magnet is an object...

.

For electric utilities
Electric utility
An electric utility is a company that engages in the generation, transmission, and distribution of electricity for sale generally in a regulated market. The electrical utility industry is a major provider of energy in most countries. It is indispensable to factories, commercial establishments,...

, it is the first process in the delivery of electricity to consumers.
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Encyclopedia
Electricity generation is the process of generating electric energy from other forms of energy
Forms of energy
In the context of physical sciences, several forms of energy have been defined. These include:These energies may be divided into two main groups; kinetic energy and potential energy. Other familiar types of energy are a varying mix of both potential and kinetic energy...

.

The fundamental principles of electricity generation were discovered during the 1820s and early 1830s by the British scientist Michael Faraday
Michael Faraday
Michael Faraday, FRS was an English chemist and physicist who contributed to the fields of electromagnetism and electrochemistry....

. His basic method is still used today: electricity is generated by the movement of a loop of wire, or disc of copper between the poles of a magnet
Magnet
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets.A permanent magnet is an object...

.

For electric utilities
Electric utility
An electric utility is a company that engages in the generation, transmission, and distribution of electricity for sale generally in a regulated market. The electrical utility industry is a major provider of energy in most countries. It is indispensable to factories, commercial establishments,...

, it is the first process in the delivery of electricity to consumers. The other processes, electricity transmission
Electric power transmission
Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...

, distribution
Electric power distribution
File:Electricity grid simple- North America.svg|thumb|380px|right|Simplified diagram of AC electricity distribution from generation stations to consumers...

, and electrical power storage and recovery using pumped storage methods are normally carried out by the electric power industry.

Electricity is most often generated at a power station
Power station
A power station is an industrial facility for the generation of electric energy....

 by electromechanical generators
Electrical generator
In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...

, primarily driven by heat engine
Heat engine
In thermodynamics, a heat engine is a system that performs the conversion of heat or thermal energy to mechanical work. It does this by bringing a working substance from a high temperature state to a lower temperature state. A heat "source" generates thermal energy that brings the working substance...

s fueled by chemical combustion
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...

 or nuclear fission
Nuclear fission
In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...

 but also by other means such as the kinetic energy
Kinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...

 of flowing water and wind. There are many other technologies that can be and are used to generate electricity such as solar photovoltaics
Photovoltaics
Photovoltaics is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material...

 and geothermal power
Geothermal power
Geothermal energy is thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. Earth's geothermal energy originates from the original formation of the planet and from radioactive decay of minerals...

.


History


Centralised power generation became possible when it was recognised that alternating current
Alternating current
In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....

 power lines can transport electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

 at very low costs across great distances by taking advantage of the ability to raise and lower the voltage
Voltage
Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...

 using power transformer
Transformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...

s.

Electricity has been generated at central stations since 1881. The first power plants were run on water power or coal, and today we rely mainly on coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

, nuclear
Nuclear power
Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...

, natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...

, hydroelectric
Hydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...

, and petroleum
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

 with a small amount from solar energy, tidal harnesses
Tidal power
Tidal power, also called tidal energy, is a form of hydropower that converts the energy of tides into useful forms of power - mainly electricity....

, wind generator
Wind generator
A wind generator is a device that generates electrical power from wind energy.Wind generators have traditionally been wind turbines, i.e. a propeller attached to an electric generator attached to appropriate electronics to attach it to the electrical grid or to charge batteries.Recently, however, a...

s, and geothermal
Geothermal power
Geothermal energy is thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. Earth's geothermal energy originates from the original formation of the planet and from radioactive decay of minerals...

 sources.

Methods of generating electricity


There are seven fundamental methods of directly transforming other forms of energy into electrical energy:
  • Static electricity
    Static electricity
    Static electricity refers to the build-up of electric charge on the surface of objects. The static charges remain on an object until they either bleed off to ground or are quickly neutralized by a discharge. Static electricity can be contrasted with current electricity, which can be delivered...

    , from the physical separation and transport of charge (examples: triboelectric effect
    Triboelectric effect
    The triboelectric effect is a type of contact electrification in which certain materials become electrically charged after they come into contact with another different material and are then separated...

     and lightning
    Lightning
    Lightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...

    )
  • Electromagnetic induction
    Electromagnetic induction
    Electromagnetic induction is the production of an electric current across a conductor moving through a magnetic field. It underlies the operation of generators, transformers, induction motors, electric motors, synchronous motors, and solenoids....

    , where an electrical generator
    Electrical generator
    In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...

    , dynamo
    Dynamo
    - Engineering :* Dynamo, a magnetic device originally used as an electric generator* Dynamo theory, a theory relating to magnetic fields of celestial bodies* Solar dynamo, the physical process that generates the Sun's magnetic field- Software :...

     or alternator
    Alternator
    An alternator is an electromechanical device that converts mechanical energy to electrical energy in the form of alternating current.Most alternators use a rotating magnetic field but linear alternators are occasionally used...

     transforms kinetic energy
    Kinetic energy
    The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...

     (energy of motion) into electricity, this is most used form for generating electricity, it is based on Faraday's law
    Faraday's law of induction
    Faraday's law of induction dates from the 1830s, and is a basic law of electromagnetism relating to the operating principles of transformers, inductors, and many types of electrical motors and generators...

    , can be experimented by simply rotating a magnet within closed loop of a conducting material (e.g Copper wire)
  • Electrochemistry
    Electrochemistry
    Electrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution.If a chemical reaction is...

    , the direct transformation of chemical energy
    Chemical energy
    Chemical energy is the potential of a chemical substance to undergo a transformation through a chemical reaction or, to transform other chemical substances...

     into electricity, as in a battery
    Battery (electricity)
    An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

    , fuel cell
    Fuel cell
    A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...

     or nerve impulse
  • Photoelectric effect
    Photoelectric effect
    In the photoelectric effect, electrons are emitted from matter as a consequence of their absorption of energy from electromagnetic radiation of very short wavelength, such as visible or ultraviolet light. Electrons emitted in this manner may be referred to as photoelectrons...

    , the transformation of light into electrical energy, as in solar cells
  • Thermoelectric effect
    Thermoelectric effect
    The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice-versa. A thermoelectric device creates a voltage when there is a different temperature on each side. Conversely, when a voltage is applied to it, it creates a temperature difference...

    , direct conversion of temperature differences to electricity, as in thermocouples, thermopiles, and Thermionic converter
    Thermionic converter
    A thermionic converter consists of a hot electrode which thermionically emits electrons over a potential energy barrier to a cooler electrode, producing a useful electric power output...

    s.

  • Piezoelectric effect, from the mechanical strain of electrically anisotropic molecules or crystals
  • Nuclear transformation, the creation and acceleration of charged particles (examples: betavoltaics
    Betavoltaics
    Betavoltaics are generators of electrical current, in effect a form of battery, which use energy from a radioactive source emitting beta particles . A common source used is the hydrogen isotope, tritium...

     or alpha particle
    Alpha particle
    Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium nucleus, which is classically produced in the process of alpha decay, but may be produced also in other ways and given the same name...

     emission)


Static electricity
Static electricity
Static electricity refers to the build-up of electric charge on the surface of objects. The static charges remain on an object until they either bleed off to ground or are quickly neutralized by a discharge. Static electricity can be contrasted with current electricity, which can be delivered...

 was the first form discovered and investigated, and the electrostatic generator
Electrostatic generator
An electrostatic generator, or electrostatic machine, is a mechanical device that produces static electricity, or electricity at high voltage and low continuous current...

 is still used even in modern devices such as the Van de Graaff generator
Van de Graaff generator
A Van de Graaff generator is an electrostatic generator which uses a moving belt to accumulate very high voltages on a hollow metal globe on the top of the stand. It was invented in 1929 by American physicist Robert J. Van de Graaff. The potential differences achieved in modern Van de Graaff...

 and MHD generator
MHD generator
The MHD generator or dynamo transforms thermal energy or kinetic energy directly into electricity. MHD generators are different from traditional electric generators in that they can operate at high temperatures without moving parts...

s. Charge carriers are separated and physically transported to a position of increased electric potential.

Almost all commercial electrical generation is done using electromagnetic induction, in which mechanical energy
Mechanical energy
In physics, mechanical energy is the sum of potential energy and kinetic energy present in the components of a mechanical system. It is the energy associated with the motion and position of an object. The law of conservation of energy states that in an isolated system that is only subject to...

 forces an electrical generator
Electrical generator
In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...

 to rotate. There are many different methods of developing the mechanical energy, including heat engines, hydro, wind and tidal power.

The direct conversion of nuclear potential energy to electricity by beta decay
Beta decay
In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...

 is used only on a small scale. In a full-size nuclear power plant, the heat of a nuclear reaction is used to run a heat engine. This drives a generator, which converts mechanical energy into electricity by magnetic induction.

Most electric generation is driven by heat engines. The combustion of fossil fuel
Fossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...

s
supplies most of the heat to these engines, with a significant fraction from nuclear fission
Nuclear fission
In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...

 and some from renewable sources. The modern steam turbine
Steam turbine
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884....

 (invented by Sir Charles Parsons
Charles Algernon Parsons
Sir Charles Algernon Parsons OM KCB FRS was an Anglo-Irish engineer, best known for his invention of the steam turbine. He worked as an engineer on dynamo and turbine design, and power generation, with great influence on the naval and electrical engineering fields...

 in 1884) currently generates about 80 percent of the electric power
Electric power
Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...

 in the world using a variety of heat sources.

Turbines


All turbines are driven by a fluid acting as an intermediate energy carrier. Many of the heat engines just mentioned are turbine
Turbine
A turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...

s. Other types of turbines can be driven by wind or falling water.

Sources include:
  • Steam - Water is boiled by:
    • Nuclear fission
      Nuclear fission
      In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...

      ,
    • The burning of fossil fuels
      Fossil fuel power plant
      A fossil-fuel power station is a power station that burns fossil fuels such as coal, natural gas or petroleum to produce electricity. Central station fossil-fuel power plants are designed on a large scale for continuous operation...

       (coal, natural gas, or petroleum). In hot gas (gas turbine), turbines are driven directly by gases produced by the combustion
      Combustion
      Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...

       of natural gas or oil. Combined cycle
      Combined cycle
      In electric power generation a combined cycle is an assembly of heat engines that work in tandem off the same source of heat, converting it into mechanical energy, which in turn usually drives electrical generators...

       gas turbine plants are driven by both steam and natural gas. They generate power by burning natural gas in a gas turbine
      Gas turbine
      A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in-between....

       and use residual heat to generate additional electricity from steam. These plants offer efficiencies of up to 60%.
    • Renewables. The steam generated by:
      • Biomass
        Biomass
        Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....

      • Solar thermal energy
        Solar thermal energy
        Solar thermal energy is a technology for harnessing solar energy for thermal energy . Solar thermal collectors are classified by the United States Energy Information Administration as low-, medium-, or high-temperature collectors. Low-temperature collectors are flat plates generally used to heat...

         (the sun as the heat source): solar parabolic troughs and solar power tower
        Solar power tower
        The solar power tower is a type of solar furnace using a tower to receive the focused sunlight. It uses an array of flat, movable mirrors to focus the sun's rays upon a collector tower...

        s concentrate sunlight to heat a heat transfer fluid, which is then used to produce steam.
      • Geothermal power
        Geothermal power
        Geothermal energy is thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. Earth's geothermal energy originates from the original formation of the planet and from radioactive decay of minerals...

        . Either steam under pressure emerges from the ground and drives a turbine or hot water evaporates a low boiling liquid to create vapour to drive a turbine.
      • Ocean thermal energy conversion
        Ocean thermal energy conversion
        Ocean Thermal Energy Conversion uses the difference between cooler deep and warmer shallow or surface ocean waters to run a heat engine and produce useful work, usually in the form of electricity....

         (OTEC ): uses the small difference between cooler deep and warmer surface ocean waters to run a heat engine (usually a turbine).

  • Other renewable sources:
    • Water (hydroelectric) - Turbine blades are acted upon by flowing water, produced by hydroelectric dams
      Hydroelectricity
      Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...

       or tidal forces
      Tidal power
      Tidal power, also called tidal energy, is a form of hydropower that converts the energy of tides into useful forms of power - mainly electricity....

      .
    • Wind - Most wind turbine
      Wind turbine
      A wind turbine is a device that converts kinetic energy from the wind into mechanical energy. If the mechanical energy is used to produce electricity, the device may be called a wind generator or wind charger. If the mechanical energy is used to drive machinery, such as for grinding grain or...

      s generate electricity from naturally occurring wind. Solar updraft tower
      Solar updraft tower
      The solar updraft tower is a renewable-energy power plant. It combines the chimney effect, the greenhouse effect and the wind turbine. Air is heated by sunshine and contained in a very large greenhouse-like structure around the base of a tall chimney, and the resulting convection causes air to...

      s use wind that is artificially produced inside the chimney by heating it with sunlight, and are more properly seen as forms of solar thermal energy.

Reciprocating engines


Small electricity generators are often powered by reciprocating engine
Reciprocating engine
A reciprocating engine, also often known as a piston engine, is a heat engine that uses one or more reciprocating pistons to convert pressure into a rotating motion. This article describes the common features of all types...

s burning diesel, biogas
Biogas
Biogas typically refers to a gas produced by the biological breakdown of organic matter in the absence of oxygen. Organic waste such as dead plant and animal material, animal dung, and kitchen waste can be converted into a gaseous fuel called biogas...

 or natural
gas. Diesel engines are often used for back up generation, usually at low voltages. However most large power grids also use diesel generators, originally provided as emergency back up for a specific facility such as a hospital, to feed power into the grid during certain circumstances. Biogas is often combusted where it is produced, such as a
landfill or wastewater treatment plant, with a reciprocating engine or a microturbine, which is a small gas turbine.


Photovoltaic panels


Unlike the solar heat concentrators mentioned above, photovoltaic panels
Photovoltaics
Photovoltaics is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material...

 convert sunlight directly to electricity. Although sunlight is free and abundant, solar 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, California and New Jersey.

Other generation methods


Various other technologies have been studied and developed for power generation. Solid-state generation (without moving parts) is of particular interest in portable applications. This area is largely dominated by thermoelectric (TE) devices, though thermionic
Thermionic converter
A thermionic converter consists of a hot electrode which thermionically emits electrons over a potential energy barrier to a cooler electrode, producing a useful electric power output...

 (TI) and thermophotovoltaic
Thermophotovoltaic
Thermophotovoltaic energy conversion is a direct conversion process from heat differentials to electricity via photons. A basic thermophotovoltaic system consists of a thermal emitter and a photovoltaic diode cell....

 (TPV) systems have been developed as well. Typically, TE devices are used at lower temperatures than TI and TPV systems. Piezoelectric devices are used for power generation from mechanical strain, particularly in power harvesting. Betavoltaics
Betavoltaics
Betavoltaics are generators of electrical current, in effect a form of battery, which use energy from a radioactive source emitting beta particles . A common source used is the hydrogen isotope, tritium...

 are another type of solid-state power generator which produces electricity from radioactive decay.
Fluid-based magnetohydrodynamic
MHD generator
The MHD generator or dynamo transforms thermal energy or kinetic energy directly into electricity. MHD generators are different from traditional electric generators in that they can operate at high temperatures without moving parts...

 (MHD) power generation has been studied as a method for extracting electrical power from nuclear reactors and also from more conventional fuel combustion systems. Osmotic power finally is another possibility at places where salt and sweet water merges (e.g. deltas, ...)

Electrochemical
Electrochemistry
Electrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution.If a chemical reaction is...

 electricity generation is also important in portable and mobile applications. Currently, most electrochemical power comes from closed electrochemical cells ("batteries
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

"), which are arguably utilized more as storage systems than generation systems, but open electrochemical systems, known as fuel cells, have been undergoing a great deal of research and development in the last few years. Fuel cells can be used to extract power either from natural fuels or from synthesized fuels (mainly electrolytic hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

) and so can be viewed as either generation systems or storage systems depending on their use.

Cost of generating electricity



Production


The production of electricity in 2008 was 20,261TWh, which was 11% of the solar energy the earth receives in one hour (174,000TWh). Sources of electricity were fossil fuels 67%, renewable energy 18%, and nuclear power 13%. The majority of fossil fuel usage for the generation of electricity was of coal and gas. Oil was only 5.5%. Ninety-two percent of renewable energy was hydroelectric followed by wind at 6% and geothermal at 1.8%. Solar photovoltaic was 0.06%, and solar thermal was 0.004%. Data are from IEA/OECD (2008)
Source of Electricity (World total year 2008)
- Coal Oil Natural
Gas
Nuclear Hydro other Total
Electricity (TWh/year) 8,263 1,111 4,301 2,731 3,288 568 20,261
Proportion 41% 5% 21% 13% 16% 3% 100%
data source IEA/OECD


Total energy consumed at all power plants for the generation of electricity was 4,398,768 ktoe (kilo ton of oil equivalent
Ton of oil equivalent
The tonne of oil equivalent is a unit of energy: the amount of energy released by burning one tonne of crude oil, approximately 42 GJ .The toe is sometimes used for large...

) which was 36% of the total for primary energy sources (TPES) of 2008.

Electricity output (gross) was 1,735,579 ktoe (20,185TWh), efficiency was 39%, and the balance of 61% was generated heat. A small part(145,141 ktoe, which was 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 289,681 ktoe.

The amount supplied to the final consumer was 1,445,285 ktoe (16,430 TWh) which was 33% of the total energy consumed at power plants and heat and power co-generation (CHP) plants.

Historical Results of Production of Electricity


Production by country



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
Electric power industry in China
The People's Republic of China's electric power industry has changed dramatically since the early 1990s to become the world's second-largest electricity consumer, after the United States. In April 1996, an Electric Power Law was implemented, a major event in China's electric power industry...

, Japan, Russia, and India.

As of Jan-2010, total electricity generation for the 2 largest generators was as follows:
USA: 3992 billion kWh (3992 TWh)
China: 3715 billion kWh (3715 TWh)

List of countries with Source of Electricity 2008


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.
Composition of Electricity by Resource (TWh per year 2008)
Country Fossil Fuel Nuclear rank Renewable Bio
other*
total rank
Coal Oil Gas sub
total
rank Hydro Geo
Thermal
Solar
PV*
Solar
Thermal
Wind Tide sub
total
rank
World total 8,263 1,111 4,301 13,675 - 2,731 - 3,288 65 12 0.9 219 0.5 3,584 - 271 20,261 -
Proportion 41% 5.5% 21% 67% - 13% - 16% 0.3% 0.06% 0.004% 1.1% 0.003% 18% - 1.3% 100% -
 Mainland China 2,733 23 31 2,788 2 68 8 585 - 0.2 - 13 - 598 1 2.4 3,457 2
 India 569 34 82 685 6 15 12 114 - 0.02 - 14 - 128 6 2.0 830 5
 United States 2,133 58 911 3,101 1 838 1 282 17 1.6 0.88 56 - 357 4 73 4,369 1
 Indonesia 61 43 25 130 19 - - 12 8.3 - - - - 20 17 - 149 20
 Brazil 13 18 29 59 23 14 13 370 - - - 0.6 - 370 3 20 463 9
 Pakistan 0.1 32 30 62 22 1.6 16 28 - - - - - 28 14 - 92 24
 Bangladesh 0.6 1.7 31 33 27 - - 1.5 - - - - - 1.5 29 - 35 27
 Nigeria - 3.1 12 15 28 - - 5.7 - - - - - 5.7 25 - 21 28
 Russia 197 16 495 708 4 163 4 167 0.5 - - 0.01 - 167 5 2.5 1,040 4
 Japan 288 139 283 711 3 258 3 83 2.8 2.3 - 2.6 - 91 7 22 1,082 3
 Mexico 21 49 131 202 13 9.8 14 39 7.1 0.01 - 0.3 - 47 12 0.8 259 14
 Philippines 16 4.9 20 40 26 - - 9.8 11 0.001 - 0.1 - 21 16 - 61 26
 Vietnam 15 1.6 30 47 25 - - 26 - - - - - 26 15 - 73 25
 Ethiopia - 0.5 - 0.5 29 - - 3.3 0.01 - - - - 3.3 28 - 3.8 30
 Egypt - 26 90 115 20 - - 15 - - - 0.9 - 16 20 - 131 22
 Germany 291 9.2 88 388 6 148 6 27 0.02 4.4 - 41 - 72 9 29 637 7
 Turkey 58 7.5 99 164 16 - - 33 0.16 - - 0.85 - 34 13 0.22 198 19
- 0.02 0.03 0.05 30 - - 7.5 - - - - - 7.5 22 - 7.5 29
 Iran 0.4 36 173 209 11 - - 5.0 - - - 0.20 - 5.2 26 - 215 17
 Thailand 32 1.7 102 135 18 - - 7.1 0.002 0.003 - - - 7.1 23 4.8 147 21
 Early Modern France 27 5.8 22 55 24 439 2 68 - 0.04 - 5.7 0.51 75 8 5.9 575 8
127 6.1 177 310 7 52 10 9.3 - 0.02 - 7.1 - 16 18 11 389 11
 Italy 49 31 173 253 9 - - 47 5.5 0.2 - 4.9 - 58 11 8.6 319 12
 South Korea 192 15 81 288 8 151 5 5.6 - 0.3 - 0.4 - 6.3 24 0.7 446 10
 Spain 50 18 122 190 14 59 9 26 - 2.6 0.02 32 - 61 10 4.3 314 13
 Canada 112 9.8 41 162 17 94 7 383 - 0.03 - 3.8 0.03 386 2 8.5 651 6
 Saudi Arabia - 116 88 204 12 - - - - - - - - - - - 204 18
 Republic of China 125 14 46 186 15 41 11 7.8 - 0.004 - 0.6 - 8.4 21 3.5 238 16
 Australia 198 2.8 39 239 10 - - 12 - 0.2 0.004 3.9 - 16 19 2.2 257 15
 Netherlands 27 2.1 63 92 21 4.2 15 0.1 - 0.04 - 4.3 - 4.4 27 6.8 108 23
Country Coal Oil Gas sub
total
rank Nuclear rank Hydro Geo
Thermal
Solar
PV
Solar
Thermal
Wind Tide sub
total
rank Bio
other
Total rank

Solar PV* is Photovoltaics
Photovoltaics
Photovoltaics is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material...



Bio other* = 198TWh (Biomass) + 69TWh (Waste) + 4TWh (other)

Environmental Concerns


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 percent of emissions, the largest of any source. Transportation emissions are close behind, contributing about one-third of U.S. production of carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

.

In the United States, fossil fuel combustion for electric power generation is responsible for 65% of all emissions of sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...

, the main component of acid rain. Electricity generation is the fourth highest combined source of NOx
NOx
NOx is a generic term for the mono-nitrogen oxides NO and NO2 . They are produced from the reaction of nitrogen and oxygen gases in the air during combustion, especially at high temperatures...

, carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...

, 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".

Water Consumption


Most large scale thermoelectric power stations consume considerable amounts of water for cooling purposes and boiler water make up - 1 L/kWh for once through (e.g. river cooling), and 1.7 L/kWh for cooling tower cooling. Water abstraction for cooling water accounts for about 40% of European total water abstraction
Water abstraction
Water abstraction, water extraction, or groundwater abstraction is the process of taking water from any source, either temporarily or permanently. Most water is used for irrigation or treatment to produce drinking water....

, although most of this water is returned to its source, albeit slightly warmer. Different cooling systems have different consumption vs. abstraction characteristics. Cooling towers withdraw a small amount of water from the environment and evaporate most of it. Once-through systems withdraw a large amount but return it to the environment immediately, at a higher temperature.

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