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113-500: Cleveland Public Power (also known as CPP ) is a publicly owned electricity generation and distribution company in Cleveland, Ohio . It was founded in 1907 by then-Cleveland mayor Tom L. Johnson . Prior to 1983, it was known as Municipal Light (or " Muny Light " for short). CPP does not have sufficient capacity to compete across the entire Greater Cleveland area. Rather, it is intended to create additional capacity and to create

226-507: A cycle ). In certain applications, like guitar amplifiers , different waveforms are used, such as triangular waves or square waves . Audio and radio signals carried on electrical wires are also examples of alternating current. These types of alternating current carry information such as sound (audio) or images (video) sometimes carried by modulation of an AC carrier signal. These currents typically alternate at higher frequencies than those used in power transmission. Electrical energy

339-403: A balanced signaling system, so that the two wires carry equal but opposite currents. Each wire in a twisted pair radiates a signal, but it is effectively cancelled by radiation from the other wire, resulting in almost no radiation loss. Coaxial cables are commonly used at audio frequencies and above for convenience. A coaxial cable has a conductive wire inside a conductive tube, separated by

452-448: A dielectric layer. The current flowing on the surface of the inner conductor is equal and opposite to the current flowing on the inner surface of the outer tube. The electromagnetic field is thus completely contained within the tube, and (ideally) no energy is lost to radiation or coupling outside the tube. Coaxial cables have acceptably small losses for frequencies up to about 5 GHz. For microwave frequencies greater than 5 GHz,

565-484: A gigawatt each. They generate about a third of the world's electricity , but cause many illnesses and the most early deaths per unit of energy produced, mainly from air pollution . World installed capacity doubled from 2000 to 2023 and increased 2% in 2023. A coal-fired power station is a type of fossil fuel power station . The coal is usually pulverized and then burned in a pulverized coal-fired boiler . The furnace heat converts boiler water to steam , which

678-545: 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 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

791-477: A power plant , energy is generated at a convenient voltage for the design of a generator , and then stepped up to a high voltage for transmission. Near the loads, the transmission voltage is stepped down to the voltages used by equipment. Consumer voltages vary somewhat depending on the country and size of load, but generally motors and lighting are built to use up to a few hundred volts between phases. The voltage delivered to equipment such as lighting and motor loads

904-402: A wall socket . The abbreviations AC and DC are often used to mean simply Alternating Current and Direct Current , respectively, as when they modify current or voltage . The usual waveform of alternating current in most electric power circuits is a sine wave , whose positive half-period corresponds with positive direction of the current and vice versa (the full period is called

1017-511: A benchmark price in order to prevent price gouging by local private utilities and prevent the private market from controlling the city's electricity supply for municipal services such as streetlights and buildings. CPP also provides power to Cleveland Browns Stadium . In December 1978, Mayor Dennis Kucinich refused to sell the company when a number of banks , which were heavily invested in Muny Light's largest privately owned competitor,

1130-440: A compromise between low frequency for traction and heavy induction motors, while still allowing incandescent lighting to operate (although with noticeable flicker). Most of the 25 Hz residential and commercial customers for Niagara Falls power were converted to 60 Hz by the late 1950s, although some 25 Hz industrial customers still existed as of the start of the 21st century. 16.7 Hz power (formerly 16 2/3 Hz)

1243-490: A direct current does not create electromagnetic waves. At very high frequencies, the current no longer flows in the wire, but effectively flows on the surface of the wire, within a thickness of a few skin depths . The skin depth is the thickness at which the current density is reduced by 63%. Even at relatively low frequencies used for power transmission (50 Hz – 60 Hz), non-uniform distribution of current still occurs in sufficiently thick conductors . For example,

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1356-437: A form of dielectric waveguides, can be used. For such frequencies, the concepts of voltages and currents are no longer used. Alternating currents are accompanied (or caused) by alternating voltages. An AC voltage v can be described mathematically as a function of time by the following equation: where The peak-to-peak value of an AC voltage is defined as the difference between its positive peak and its negative peak. Since

1469-451: A generator are photovoltaic solar and fuel cells . 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

1582-645: 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

1695-459: A higher voltage requires less loss-producing current than for the same power at a lower voltage. Power is often transmitted at hundreds of kilovolts on pylons , and transformed down to tens of kilovolts to be transmitted on lower level lines, and finally transformed down to 100 V – 240 V for domestic use. High voltages have disadvantages, such as the increased insulation required, and generally increased difficulty in their safe handling. In

1808-408: 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

1921-542: A large number of consumers. Most power plants used in centralised generation are thermal power plants meaning that they use a fuel to heat steam to produce a pressurised gas which in turn spins a turbine and generates electricity. This is the traditional way of producing energy. This process relies on several forms of technology to produce widespread electricity, these being natural coal, gas and nuclear forms of thermal generation. More recently solar and wind have become large scale. A photovoltaic power station , also known as

2034-957: A lighting system where sets of induction coils were installed along a high voltage AC line. Instead of changing voltage, the primary windings transferred power to the secondary windings which were connected to one or several 'electric candles' (arc lamps) of his own design, used to keep the failure of one lamp from disabling the entire circuit. In 1878, the Ganz factory , Budapest, Hungary, began manufacturing equipment for electric lighting and, by 1883, had installed over fifty systems in Austria-Hungary . Their AC systems used arc and incandescent lamps, generators, and other equipment. Alternating current systems can use transformers to change voltage from low to high level and back, allowing generation and consumption at low voltages but transmission, possibly over great distances, at high voltage, with savings in

2147-536: A prime source of power within isolated villages. Total world generation in 2021 was 28,003 TWh, including coal (36%), gas (23%), hydro (15%), nuclear (10%), wind (6.6%), solar (3.7%), oil and other fossil fuels (3.1%), biomass (2.4%) and geothermal and other renewables (0.33%). China produced a third of the world's electricity in 2021, largely from coal. The United States produces half as much as China but uses far more natural gas and nuclear. Variations between countries generating electrical power affect concerns about

2260-441: A scale of at least 1 MW p . As of 2018, the world's largest operating photovoltaic power stations surpassed 1 gigawatt . At the end of 2019, about 9,000 solar farms were larger than 4 MW AC (utility scale), with a combined capacity of over 220 GW AC . A wind farm or wind park, or wind power plant, is a group of wind turbines in the same location used to produce electricity . Wind farms vary in size from

2373-522: A single center-tapped transformer giving two live conductors, is a common distribution scheme for residential and small commercial buildings in North America. This arrangement is sometimes incorrectly referred to as "two phase". A similar method is used for a different reason on construction sites in the UK. Small power tools and lighting are supposed to be supplied by a local center-tapped transformer with

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2486-544: A small number of turbines to several hundred wind turbines covering an extensive area. Wind farms can be either onshore or offshore . Many of the largest operational onshore wind farms are located in China, India, and the United States. For example, the largest wind farm in the world , Gansu Wind Farm in China had a capacity of over 6,000  MW by 2012, with a goal of 20,000 MW by 2020. As of December 2020,

2599-465: A solar park, solar farm, or solar power plant, is a large-scale grid-connected photovoltaic power system (PV system) designed for the supply of merchant power . They are different from most building-mounted and other decentralized solar power because they supply power at the utility level, rather than to a local user or users. Utility-scale solar is sometimes used to describe this type of project. This approach differs from concentrated solar power ,

2712-555: A voltage of 55 V between each power conductor and earth. This significantly reduces the risk of electric shock in the event that one of the live conductors becomes exposed through an equipment fault whilst still allowing a reasonable voltage of 110 V between the two conductors for running the tools. A third wire , called the bond (or earth) wire, is often connected between non-current-carrying metal enclosures and earth ground. This conductor provides protection from electric shock due to accidental contact of circuit conductors with

2825-403: A wire that is made of a non-perfect conductor (a conductor with finite, rather than infinite, electrical conductivity) pushes the alternating current, along with their associated electromagnetic fields, away from the wire's center. The phenomenon of alternating current being pushed away from the center of the conductor is called skin effect , and a direct current does not exhibit this effect, since

2938-470: Is 230 × R × W × 2 {\displaystyle 230\times R\times W\times 2} , that is 460 RW. During the course of one cycle (two cycle as the power) the voltage rises from zero to 325 V, the power from zero to 460 RW, and both falls through zero. Next, the voltage descends to reverse direction, -325 V, but the power ascends again to 460 RW, and both returns to zero. Alternating current

3051-462: 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

3164-515: Is an electric current that periodically reverses direction and changes its magnitude continuously with time ranging between some maximum and minimum values, in contrast to direct current (DC), which flows only in one direction. Alternating current is the type of electric current through which electric power is delivered to businesses and residences, and it is the type of electric current that consumers typically use when they plug kitchen appliances , televisions , fans and electric lamps into

3277-468: Is based upon the local power requirement and the fluctuations in demand. All power grids have varying loads on them. 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. Nuclear power plants can produce

3390-530: Is called Litz wire . This measure helps to partially mitigate skin effect by forcing more equal current throughout the total cross section of the stranded conductors. Litz wire is used for making high-Q inductors , reducing losses in flexible conductors carrying very high currents at lower frequencies, and in the windings of devices carrying higher radio frequency current (up to hundreds of kilohertz), such as switch-mode power supplies and radio frequency transformers . As written above, an alternating current

3503-505: Is distributed as alternating current because AC voltage may be increased or decreased with a transformer . This allows the power to be transmitted through power lines efficiently at high voltage , which reduces the energy lost as heat due to resistance of the wire, and transformed to a lower, safer voltage for use. Use of a higher voltage leads to significantly more efficient transmission of power. The power losses ( P w {\displaystyle P_{\rm {w}}} ) in

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3616-439: Is double of the one of the voltage's. To illustrate these concepts, consider a 230 V AC mains supply used in many countries around the world. It is so called because its root mean square value is 230 V. This means that the time-averaged power delivered P average {\displaystyle P_{\text{average}}} is equivalent to the power delivered by a DC voltage of 230 V. To determine

3729-975: 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: Turbines can also use other heat-transfer liquids than steam. Supercritical carbon dioxide based cycles can provide higher conversion efficiency due to faster heat exchange, higher energy density and simpler power cycle infrastructure. Supercritical carbon dioxide blends , that are currently in development, can further increase efficiency by optimizing its critical pressure and temperature points. 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

3842-511: Is fundamentally the opposite of distributed generation . Distributed generation is the small-scale generation of electricity to smaller groups of consumers. This can also include independently producing electricity by either solar or wind power. In recent years distributed generation as has seen a spark in popularity due to its propensity to use renewable energy generation methods such as rooftop solar . Centralised energy sources are large power plants that produce huge amounts of electricity to

3955-469: Is made of electric charge under periodic acceleration , which causes radiation of electromagnetic waves . Energy that is radiated is lost. Depending on the frequency, different techniques are used to minimize the loss due to radiation. At frequencies up to about 1 GHz, pairs of wires are twisted together in a cable, forming a twisted pair . This reduces losses from electromagnetic radiation and inductive coupling . A twisted pair must be used with

4068-735: 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

4181-521: Is probably by Guillaume Duchenne , inventor and developer of electrotherapy . In 1855, he announced that AC was superior to direct current for electrotherapeutic triggering of muscle contractions. Alternating current technology was developed further by the Hungarian Ganz Works company (1870s), and in the 1880s: Sebastian Ziani de Ferranti , Lucien Gaulard , and Galileo Ferraris . In 1876, Russian engineer Pavel Yablochkov invented

4294-577: 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 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 uses electromagnetic induction, in which mechanical energy forces

4407-472: Is rated in megawatt-peak (MW p ), which refers to the solar array's theoretical maximum DC power output. In other countries, the manufacturer states the surface and the efficiency. However, Canada, Japan, Spain, and the United States often specify using the converted lower nominal power output in MW AC , a measure more directly comparable to other forms of power generation. Most solar parks are developed at

4520-446: Is standardized, with an allowable range of voltage over which equipment is expected to operate. Standard power utilization voltages and percentage tolerance vary in the different mains power systems found in the world. High-voltage direct-current (HVDC) electric power transmission systems have become more viable as technology has provided efficient means of changing the voltage of DC power. Transmission with high voltage direct current

4633-568: Is still used in some European rail systems, such as in Austria , Germany , Norway , Sweden and Switzerland . Off-shore, military, textile industry, marine, aircraft, and spacecraft applications sometimes use 400 Hz, for benefits of reduced weight of apparatus or higher motor speeds. Computer mainframe systems were often powered by 400 Hz or 415 Hz for benefits of ripple reduction while using smaller internal AC to DC conversion units. A direct current flows uniformly throughout

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4746-429: Is then used to spin turbines that turn generators . Thus chemical energy stored in coal is converted successively into thermal energy , mechanical energy and, finally, electrical energy . Natural gas is ignited to create pressurised gas which is used to spin turbines to generate electricity. Natural gas plants use a gas turbine where natural gas is added along with oxygen which in turn combusts and expands through

4859-422: Is therefore V peak − ( − V peak ) = 2 V peak {\displaystyle V_{\text{peak}}-(-V_{\text{peak}})=2V_{\text{peak}}} . Below an AC waveform (with no DC component ) is assumed. The RMS voltage is the square root of the mean over one cycle of the square of the instantaneous voltage. The relationship between voltage and

4972-425: Is used to transmit information , as in the cases of telephone and cable television . Information signals are carried over a wide range of AC frequencies. POTS telephone signals have a frequency of about 3 kHz, close to the baseband audio frequency. Cable television and other cable-transmitted information currents may alternate at frequencies of tens to thousands of megahertz. These frequencies are similar to

5085-562: The Cleveland Electric Illuminating Company (better known as CEI or The Illuminating Company) refused to roll over the city's debt, as had previously been customary. This was seen as a bad move at the time; unable to pay its debts, the city became the first since the Great Depression to enter default , which cost Kucinich his job in next year's mayoral election . However, Kucinich's decision

5198-676: The Three Mile Island accident , Chernobyl disaster and the Fukushima nuclear disaster illustrate this problem. The table lists 45 countries with their total electricity capacities. The data is from 2022. According to the Energy Information Administration , the total global electricity capacity in 2022 was nearly 8.9 terawatt (TW), more than four times the total global electricity capacity in 1981. The global average per-capita electricity capacity

5311-786: The Westinghouse Electric in Pittsburgh, Pennsylvania, on January 8, 1886. The new firm became active in developing alternating current (AC) electric infrastructure throughout the United States. The Edison Electric Light Company held an option on the US rights for the Ganz ZBD transformers, requiring Westinghouse to pursue alternative designs on the same principles. George Westinghouse had bought Gaulard and Gibbs' patents for $ 50,000 in February 1886. He assigned to William Stanley

5424-429: The steam turbine had a massive impact on the efficiency of electrical generation but also the economics of generation as well. This conversion of heat energy into mechanical work was similar to that of steam engines , however at a significantly larger scale and far more productively. The improvements of these large-scale generation plants were critical to the process of centralised generation as they would become vital to

5537-451: The 1218 MW Hornsea Wind Farm in the UK is the largest offshore wind farm in the world . Individual wind turbine designs continue to increase in power , resulting in fewer turbines being needed for the same total output. A coal-fired power station or coal power plant is a thermal power station which burns coal to generate electricity . Worldwide there are about 2,500 coal-fired power stations, on average capable of generating

5650-481: The 1880s the popularity of electricity grew massively with the introduction of the Incandescent light bulb . Although there are 22 recognised inventors of the light bulb prior to Joseph Swan and Thomas Edison , Edison and Swan's invention became by far the most successful and popular of all. During the early years of the 19th century, massive jumps in electrical sciences were made. And by the later 19th century

5763-752: The AC system at the Grosvenor Gallery power station in 1886 for the London Electric Supply Corporation (LESCo) including alternators of his own design and open core transformer designs with serial connections for utilization loads - similar to Gaulard and Gibbs. In 1890, he designed their power station at Deptford and converted the Grosvenor Gallery station across the Thames into an electrical substation , showing

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5876-580: The Northern America in the 1920s in large cities and urban areas. It was not until the 1930s that rural areas saw the large-scale establishment of electrification. 2021 world electricity generation by source. Total generation was 28 petawatt-hours . 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

5989-549: 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 NO x , carbon monoxide , and particulate matter in the US. According to the International Energy Agency (IEA), low-carbon electricity generation needs to account for 85% of global electrical output by 2040 in order to ward off

6102-508: The ability to store the flow of water is limited and the load varies too much during the annual production cycle. 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 forms of electricity production that do not employ

6215-411: The advancement of electrical technology and engineering led to electricity being part of everyday life. With the introduction of many electrical inventions and their implementation into everyday life, the demand for electricity within homes grew dramatically. With this increase in demand, the potential for profit was seen by many entrepreneurs who began investing into electrical systems to eventually create

6328-487: The atmosphere. Nuclear power plants can also create district heating and desalination projects, limiting carbon emissions and the need for expanded electrical output. A fundamental issue regarding centralised generation and the current electrical generation methods in use today is the significant negative environmental effects that many of the generation processes have. Processes such as coal and gas not only release carbon dioxide as they combust, but their extraction from

6441-413: The biggest difference being that waveguides have no inner conductor. Waveguides can have any arbitrary cross section, but rectangular cross sections are the most common. Because waveguides do not have an inner conductor to carry a return current, waveguides cannot deliver energy by means of an electric current , but rather by means of a guided electromagnetic field . Although surface currents do flow on

6554-547: The city of Pomona, California , which was 14 miles away. Meanwhile, the possibility of transferring electrical power from a waterfall at a distance was explored at the Grängesberg mine in Sweden. A 45  m fall at Hällsjön, Smedjebackens kommun, where a small iron work had been located, was selected. In 1893, a three-phase 9.5  kv system was used to transfer 400 horsepower a distance of 15  km , becoming

6667-507: The cost of conductors and energy losses. A bipolar open-core power transformer developed by Lucien Gaulard and John Dixon Gibbs was demonstrated in London in 1881, and attracted the interest of Westinghouse . They also exhibited the invention in Turin in 1884. However, these early induction coils with open magnetic circuits are inefficient at transferring power to loads . Until about 1880,

6780-616: 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

6893-514: The cross-section of a homogeneous electrically conducting wire. An alternating current of any frequency is forced away from the wire's center, toward its outer surface. This is because an alternating current (which is the result of the acceleration of electric charge ) creates electromagnetic waves (a phenomenon known as electromagnetic radiation ). Electric conductors are not conducive to electromagnetic waves (a perfect electric conductor prohibits all electromagnetic waves within its boundary), so

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7006-411: The cross-sectional area. A conductor's AC resistance is higher than its DC resistance, causing a higher energy loss due to ohmic heating (also called I R loss). For low to medium frequencies, conductors can be divided into stranded wires, each insulated from the others, with the relative positions of individual strands specially arranged within the conductor bundle. Wire constructed using this technique

7119-572: The deployment of solar panels. Installed capacity is growing by around 20% 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. Hydroelectric plants , nuclear power plants , thermal power plants and renewable sources have their own pros and cons, and selection

7232-476: The design of electric motors, particularly for hoisting, crushing and rolling applications, and commutator-type traction motors for applications such as railways . However, low frequency also causes noticeable flicker in arc lamps and incandescent light bulbs . The use of lower frequencies also provided the advantage of lower transmission losses, which are proportional to frequency. The original Niagara Falls generators were built to produce 25 Hz power, as

7345-508: The electrical system to a safe state. All bond wires are bonded to ground at the main service panel, as is the neutral/identified conductor if present. The frequency of the electrical system varies by country and sometimes within a country; most electric power is generated at either 50 or 60  Hertz . Some countries have a mixture of 50 Hz and 60 Hz supplies, notably electricity power transmission in Japan . A low frequency eases

7458-533: The electricity through high voltage transmission lines to a substation, where it is then distributed to consumers; the basic concept being that multi-megawatt or gigawatt scale large stations create electricity for a large number of people. The vast majority of electricity used is created from centralised generation. Most centralised power generation comes from large power plants run by fossil fuels such as coal or natural gas, though nuclear or large hydroelectricity plants are also commonly used. Centralised generation

7571-522: The electromagnetic wave frequencies often used to transmit the same types of information over the air . The first alternator to produce alternating current was an electric generator based on Michael Faraday 's principles constructed by the French instrument maker Hippolyte Pixii in 1832. Pixii later added a commutator to his device to produce the (then) more commonly used direct current. The earliest recorded practical application of alternating current

7684-524: The entire power system that we now use today. Throughout the middle of the 20th century many utilities began merging their distribution networks due to economic and efficiency benefits. Along with the invention of long-distance power transmission , the coordination of power plants began to form. This system was then secured by regional system operators to ensure stability and reliability. The electrification of homes began in Northern Europe and in

7797-404: 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. Methane leaks (from natural gas to fuel gas-fired power plants) and carbon dioxide emissions from fossil fuel-based electricity generation account for a significant portion of world greenhouse gas emissions . In

7910-414: The experiments; In their joint 1885 patent applications for novel transformers (later called ZBD transformers), they described two designs with closed magnetic circuits where copper windings were either wound around a ring core of iron wires or else surrounded by a core of iron wires. In both designs, the magnetic flux linking the primary and secondary windings traveled almost entirely within the confines of

8023-479: The first commercial application. In 1893, Westinghouse built an alternating current system for the Chicago World Exposition . In 1893, Decker designed the first American commercial three-phase power plant using alternating current—the hydroelectric Mill Creek No. 1 Hydroelectric Plant near Redlands, California . Decker's design incorporated 10 kV three-phase transmission and established

8136-428: The first electricity public utilities. This process in history is often described as electrification. The earliest distribution of electricity came from companies operating independently of one another. A consumer would purchase electricity from a producer, and the producer would distribute it through their own power grid. As technology improved so did the productivity and efficiency of its generation. Inventions such as

8249-495: The fusion reaction (see magnetohydrodynamics ). Phasing out coal-fired power stations and eventually gas-fired power stations , or, if practical, capturing their greenhouse gas emissions , is an important part of the energy transformation required to limit climate change . Vastly more solar power and wind power is forecast to be required, with electricity demand increasing strongly with further electrification of transport , homes and industry. However, in 2023, it

8362-420: The generators. Although there are several types of nuclear reactors, all fundamentally use this process. Normal emissions due to nuclear power plants are primarily waste heat and radioactive spent fuel. In a reactor accident, significant amounts of radioisotopes can be released to the environment, posing a long term hazard to life. This hazard has been a continuing concern of environmentalists. Accidents such as

8475-494: The ground also impacts the environment. Open pit coal mines use large areas of land to extract coal and limit the potential for productive land use after the excavation. Natural gas extraction releases large amounts of methane into the atmosphere when extracted from the ground greatly increase global greenhouse gases. Although nuclear power plants do not release carbon dioxide through electricity generation, there are risks associated with nuclear waste and safety concerns associated with

8588-458: The heat input is from the process of nuclear fission . Currently, nuclear power produces 11% of all electricity in the world. Most nuclear reactors use uranium as a source of fuel. In a process called nuclear fission , energy, in the form of heat, is released when nuclear atoms are split. Electricity is created through the use of a nuclear reactor where heat produced by nuclear fission is used to produce steam which in turn spins turbines and powers

8701-564: The inner walls of the waveguides, those surface currents do not carry power. Power is carried by the guided electromagnetic fields. The surface currents are set up by the guided electromagnetic fields and have the effect of keeping the fields inside the waveguide and preventing leakage of the fields to the space outside the waveguide. Waveguides have dimensions comparable to the wavelength of the alternating current to be transmitted, so they are feasible only at microwave frequencies. In addition to this mechanical feasibility, electrical resistance of

8814-511: The iron core, with no intentional path through air (see toroidal cores ). The new transformers were 3.4 times more efficient than the open-core bipolar devices of Gaulard and Gibbs. The Ganz factory in 1884 shipped the world's first five high-efficiency AC transformers. This first unit had been manufactured to the following specifications: 1,400 W, 40 Hz, 120:72 V, 11.6:19.4 A, ratio 1.67:1, one-phase, shell form. The ZBD patents included two other major interrelated innovations: one concerning

8927-625: The limitations of the direct current system. In 1886, the ZBD engineers designed the world's first power station that used AC generators to power a parallel-connected common electrical network, the steam-powered Rome-Cerchi power plant. The reliability of the AC technology received impetus after the Ganz Works electrified a large European metropolis: Rome in 1886. Building on the advancement of AC technology in Europe, George Westinghouse founded

9040-429: The losses (due mainly to the dielectric separating the inner and outer tubes being a non-ideal insulator) become too large, making waveguides a more efficient medium for transmitting energy. Coaxial cables often use a perforated dielectric layer to separate the inner and outer conductors in order to minimize the power dissipated by the dielectric. Waveguides are similar to coaxial cables, as both consist of tubes, with

9153-419: The lower speed is preferable for larger machines. If the load on a three-phase system is balanced equally among the phases, no current flows through the neutral point . Even in the worst-case unbalanced (linear) load, the neutral current will not exceed the highest of the phase currents. Non-linear loads (e.g. the switch-mode power supplies widely used) may require an oversized neutral bus and neutral conductor in

9266-484: The main street of Great Barrington. The spread of Westinghouse and other AC systems triggered a push back in late 1887 by Thomas Edison (a proponent of direct current), who attempted to discredit alternating current as too dangerous in a public campaign called the " war of the currents ". In 1888, alternating current systems gained further viability with introduction of a functional AC motor , something these systems had lacked up till then. The design, an induction motor ,

9379-469: 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

9492-538: The maximum value of sin ⁡ ( x ) {\displaystyle \sin(x)} is +1 and the minimum value is −1, an AC voltage swings between + V peak {\displaystyle +V_{\text{peak}}} and − V peak {\displaystyle -V_{\text{peak}}} . The peak-to-peak voltage, usually written as V pp {\displaystyle V_{\text{pp}}} or V P-P {\displaystyle V_{\text{P-P}}} ,

9605-469: The metal chassis of portable appliances and tools. Bonding all non-current-carrying metal parts into one complete system ensures there is always a low electrical impedance path to ground sufficient to carry any fault current for as long as it takes for the system to clear the fault. This low impedance path allows the maximum amount of fault current, causing the overcurrent protection device (breakers, fuses) to trip or burn out as quickly as possible, bringing

9718-425: The non-ideal metals forming the walls of the waveguide causes dissipation of power (surface currents flowing on lossy conductors dissipate power). At higher frequencies, the power lost to this dissipation becomes unacceptably large. At frequencies greater than 200 GHz, waveguide dimensions become impractically small, and the ohmic losses in the waveguide walls become large. Instead, fiber optics , which are

9831-425: The other major large-scale solar generation technology, which uses heat to drive a variety of conventional generator systems. Both approaches have their own advantages and disadvantages, but to date, for a variety of reasons, photovoltaic technology has seen much wider use. As of 2019 , about 97% of utility-scale solar power capacity was PV. In some countries, the nameplate capacity of photovoltaic power stations

9944-435: The paradigm for AC power transmission from a high voltage supply to a low voltage load was a series circuit. Open-core transformers with a ratio near 1:1 were connected with their primaries in series to allow use of a high voltage for transmission while presenting a low voltage to the lamps. The inherent flaw in this method was that turning off a single lamp (or other electric device) affected the voltage supplied to all others on

10057-431: The peak voltage (amplitude), we can rearrange the above equation to: For 230 V AC, the peak voltage V peak {\displaystyle V_{\text{peak}}} is therefore 230  V × 2 {\displaystyle 230{\text{ V}}\times {\sqrt {2}}} , which is about 325 V, and the peak power P peak {\displaystyle P_{\text{peak}}}

10170-610: The power delivered is: where R {\displaystyle R} represents a load resistance. Rather than using instantaneous power, p ( t ) {\displaystyle p(t)} , it is more practical to use a time-averaged power (where the averaging is performed over any integer number of cycles). Therefore, AC voltage is often expressed as a root mean square (RMS) value, written as V rms {\displaystyle V_{\text{rms}}} , because For this reason, AC power's waveform becomes Full-wave rectified sine, and its fundamental frequency

10283-492: The same circuit. Many adjustable transformer designs were introduced to compensate for this problematic characteristic of the series circuit, including those employing methods of adjusting the core or bypassing the magnetic flux around part of a coil. The direct current systems did not have these drawbacks, giving it significant advantages over early AC systems. In the UK, Sebastian de Ferranti , who had been developing AC generators and transformers in London since 1882, redesigned

10396-414: The same phases with reverse polarity and so can be simply wired together. In practice, higher "pole orders" are commonly used. For example, a 12-pole machine would have 36 coils (10° spacing). The advantage is that lower rotational speeds can be used to generate the same frequency. For example, a 2-pole machine running at 3600 rpm and a 12-pole machine running at 600 rpm produce the same frequency;

10509-411: The skin depth of a copper conductor is approximately 8.57 mm at 60 Hz, so high current conductors are usually hollow to reduce their mass and cost. This tendency of alternating current to flow predominantly in the periphery of conductors reduces the effective cross-section of the conductor. This increases the effective AC resistance of the conductor, since resistance is inversely proportional to

10622-585: The standards for the complete system of generation, transmission and motors used in USA today. The original Niagara Falls Adams Power Plant with three two-phase generators was put into operation in August 1895, but was connected to the remote transmission system only in 1896. The Jaruga Hydroelectric Power Plant in Croatia was set in operation two days later, on 28 August 1895. Its generator (42 Hz, 240 kW)

10735-410: The supply side. For smaller customers (just how small varies by country and age of the installation) only a single phase and neutral, or two phases and neutral, are taken to the property. For larger installations all three phases and neutral are taken to the main distribution panel. From the three-phase main panel, both single and three-phase circuits may lead off. Three-wire single-phase systems, with

10848-646: The task of redesigning the Gaulard and Gibbs transformer for commercial use in United States. On March 20, 1886, Stanley conducted a demonstrative experiment in Great Barrington : A Siemens generator's voltage of 500 volts was converted into 3000 volts, and then the voltage was stepped down to 500 volts by six Westinghouse transformers. With this setup, the Westinghouse company successfully powered thirty 100-volt incandescent bulbs in twenty shops along

10961-444: The turbine to force a generator to spin. Natural gas power plants are more efficient than coal power generation, they however contribute to climate change, but not as highly as coal generation. Not only do they produce carbon dioxide from the ignition of natural gas, the extraction of gas when mined releases a significant amount of methane into the atmosphere. Nuclear power plants create electricity through steam turbines where

11074-403: The upstream distribution panel to handle harmonics . Harmonics can cause neutral conductor current levels to exceed that of one or all phase conductors. For three-phase at utilization voltages a four-wire system is often used. When stepping down three-phase, a transformer with a Delta (3-wire) primary and a Star (4-wire, center-earthed) secondary is often used so there is no need for a neutral on

11187-413: The use of nuclear sources. Per unit of electricity generated coal and gas-fired power life-cycle greenhouse gas emissions are almost always at least ten times that of other generation methods. Centralised generation is electricity generation by large-scale centralised facilities, sent through transmission lines to consumers. These facilities are usually located far away from consumers and distribute

11300-578: The use of parallel connected, instead of series connected, utilization loads, the other concerning the ability to have high turns ratio transformers such that the supply network voltage could be much higher (initially 1400 V to 2000 V) than the voltage of utilization loads (100 V initially preferred). When employed in parallel connected electric distribution systems, closed-core transformers finally made it technically and economically feasible to provide electric power for lighting in homes, businesses and public spaces. The other essential milestone

11413-519: The way to integrate older plants into a universal AC supply system. In the autumn of 1884, Károly Zipernowsky , Ottó Bláthy and Miksa Déri (ZBD), three engineers associated with the Ganz Works of Budapest, determined that open-core devices were impractical, as they were incapable of reliably regulating voltage. Bláthy had suggested the use of closed cores, Zipernowsky had suggested the use of parallel shunt connections , and Déri had performed

11526-477: The wire are a product of the square of the current ( I ) and the resistance (R) of the wire, described by the formula: This means that when transmitting a fixed power on a given wire, if the current is halved (i.e. the voltage is doubled), the power loss due to the wire's resistance will be reduced to one quarter. The power transmitted is equal to the product of the current and the voltage (assuming no phase difference); that is, Consequently, power transmitted at

11639-698: The worst effects of climate change. Like other organizations including the Energy Impact Center (EIC) and the United Nations Economic Commission for Europe (UNECE), the IEA has called for the expansion of nuclear and renewable energy to meet that objective. Some, like EIC founder Bret Kugelmass, believe that nuclear power is the primary method for decarbonizing electricity generation because it can also power direct air capture that removes existing carbon emissions from

11752-586: Was about 1,120 watts in 2022, nearly two and a half times the global average per-capita electricity capacity in 1981. Iceland has the highest installed capacity per capita in the world, at about 8,990 watts. All developed countries have an average per-capita electricity capacity above the global average per-capita electricity capacity, with the United Kingdom having the lowest average per-capita electricity capacity of all other developed countries. Alternating current Alternating current ( AC )

11865-505: Was independently invented by Galileo Ferraris and Nikola Tesla (with Tesla's design being licensed by Westinghouse in the US). This design was independently further developed into the modern practical three-phase form by Mikhail Dolivo-Dobrovolsky and Charles Eugene Lancelot Brown in Germany on one side, and Jonas Wenström in Sweden on the other, though Brown favoured the two-phase system. A long-distance alternating current transmission

11978-547: Was installed in Telluride Colorado. The first three-phase system was established in 1891 in Frankfurt , Germany. The Tivoli – Rome transmission was completed in 1892. The San Antonio Canyon Generator was the third commercial single-phase hydroelectric AC power plant in the United States to provide long-distance electricity. It was completed on December 31, 1892, by Almarian William Decker to provide power to

12091-400: Was later vindicated by both city officials and the U.S. Senate , which found that CEI and the banks had acted improperly. In December 2006, a new commissioner for CPP, Ivan Henderson, took over the reins from the incumbent James Majer. Under the new commissioner's guidance CPP is poised to take over the streetlight maintenance from CEI. Electricity generation Consumable electricity

12204-507: Was made and installed by the Hungarian company Ganz , while the transmission line from the power plant to the City of Šibenik was 11.5 kilometers (7.1 mi) long, and the municipal distribution grid 3000 V/110 V included six transforming stations. Alternating current circuit theory developed rapidly in the latter part of the 19th and early 20th century. Notable contributors to

12317-596: Was not feasible in the early days of electric power transmission , as there was then no economically viable way to step the voltage of DC down for end user applications such as lighting incandescent bulbs. Three-phase electrical generation is very common. The simplest way is to use three separate coils in the generator stator , physically offset by an angle of 120° (one-third of a complete 360° phase) to each other. Three current waveforms are produced that are equal in magnitude and 120° out of phase to each other. If coils are added opposite to these (60° spacing), they generate

12430-497: 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. In

12543-409: Was reported that the global electricity supply was approaching peak CO2 emissions thanks to the growth of solar and wind 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

12656-506: Was the introduction of 'voltage source, voltage intensive' (VSVI) systems' by the invention of constant voltage generators in 1885. In early 1885, the three engineers also eliminated the problem of eddy current losses with the invention of the lamination of electromagnetic cores. Ottó Bláthy also invented the first AC electricity meter . The AC power system was developed and adopted rapidly after 1886 due to its ability to distribute electricity efficiently over long distances, overcoming

12769-754: Was used in 1883 for the Metropolitan Railway station lighting in London , while the single-phase 1884 system in Turin , Italy, was the first multiple-user AC distribution system in the world. The Ames Hydroelectric Generating Plant , constructed in 1890, was among the first hydroelectric alternating current power plants. A long distance transmission of single-phase electricity from a hydroelectric generating plant in Oregon at Willamette Falls sent power fourteen miles downriver to downtown Portland for street lighting in 1890. In 1891, another transmission system

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