Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit. The SI unit of power is one joule per second. Electric power is produced by electric generators, but can be supplied by sources such as electric batteries, it is supplied to businesses and homes by the electric power industry through an electric power grid. Electric power is sold by the kilowatt hour, the product of the power in kilowatts multiplied by running time in hours. Electric utilities measure power using an electricity meter, which keeps a running total of the electric energy delivered to a customer. Electrical power provides a low entropy form of energy and can be carried long distances and converted into other forms of energy such as motion, light or heat with high energy efficiency. Electric power, like mechanical power, is the rate of doing work, measured in watts, represented by the letter P; the term wattage is used colloquially to mean "electric power in watts." The electric power in watts produced by an electric current I consisting of a charge of Q coulombs every t seconds passing through an electric potential difference of V is P = work done per unit time = V Q t = V I where Q is electric charge in coulombs t is time in seconds I is electric current in amperes V is electric potential or voltage in volts Electric power is transformed to other forms of energy when electric charges move through an electric potential difference, which occurs in electrical components in electric circuits.
From the standpoint of electric power, components in an electric circuit can be divided into two categories: Passive devices or loads: When electric charges move through a potential difference from a higher to a lower voltage, when conventional current moves from the positive terminal to the negative terminal, work is done by the charges on the device. The potential energy of the charges due to the voltage between the terminals is converted to kinetic energy in the device; these devices are called passive loads. Examples are electrical appliances, such as light bulbs, electric motors, electric heaters. In alternating current circuits the direction of the voltage periodically reverses, but the current always flows from the higher potential to the lower potential side. Active devices or power sources: If the charges are moved by an'exterior force' through the device in the direction from the lower electric potential to the higher, work will be done on the charges, energy is being converted to electric potential energy from some other type of energy, such as mechanical energy or chemical energy.
Devices in which this occurs are called active devices or power sources. Some devices can current through them. For example, a rechargeable battery acts as a source when it provides power to a circuit, but as a load when it is connected to a battery charger and is being recharged, or a generator as a power source and a motor as a load. Since electric power can flow either into or out of a component, a convention is needed for which direction represents positive power flow. Electric power flowing out of a circuit into a component is arbitrarily defined to have a positive sign, while power flowing into a circuit from a component is defined to have a negative sign, thus passive components have positive power consumption, while power sources have negative power consumption. This is called the passive sign convention. In the case of resistive loads, Joule's law can be combined with Ohm's law to produce alternative expressions for the amount of power, dissipated: P = I V = I 2 R = V 2 R, where R is the electrical resistance.
In alternating current circuits, energy storage elements such as inductance and capacitance may result in periodic reversals of the direction of energy flow. The portion of power flow that, averaged over a complete cycle of the AC waveform, results in net transfer of energy in one direction is known as real power; that portion of power flow due to stored energy, that returns to the source in each cycle, is known as reactive power. The real power P in watts consumed by a device is given by P = 1 2 V p I p cos θ = V r m s I r m s cos θ where Vp is the peak voltage in volts Ip is the peak current in amperes Vrms is the root-mean-square voltage in volts Irms is the root-mean-square current in amperes θ is the phase angle between the current and voltage sine waves The relationship between real power, reactive power and apparent power can be expressed by representing the quantities as vectors. Real power is represented as a horizontal vector and reactive power is represented as a vertical vector.
The apparent power vector is the hypotenuse o
Frequency is the number of occurrences of a repeating event per unit of time. It is referred to as temporal frequency, which emphasizes the contrast to spatial frequency and angular frequency; the period is the duration of time of one cycle in a repeating event, so the period is the reciprocal of the frequency. For example: if a newborn baby's heart beats at a frequency of 120 times a minute, its period—the time interval between beats—is half a second. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals, radio waves, light. For cyclical processes, such as rotation, oscillations, or waves, frequency is defined as a number of cycles per unit time. In physics and engineering disciplines, such as optics and radio, frequency is denoted by a Latin letter f or by the Greek letter ν or ν; the relation between the frequency and the period T of a repeating event or oscillation is given by f = 1 T.
The SI derived unit of frequency is the hertz, named after the German physicist Heinrich Hertz. One hertz means. If a TV has a refresh rate of 1 hertz the TV's screen will change its picture once a second. A previous name for this unit was cycles per second; the SI unit for period is the second. A traditional unit of measure used with rotating mechanical devices is revolutions per minute, abbreviated r/min or rpm. 60 rpm equals one hertz. As a matter of convenience and slower waves, such as ocean surface waves, tend to be described by wave period rather than frequency. Short and fast waves, like audio and radio, are described by their frequency instead of period; these used conversions are listed below: Angular frequency denoted by the Greek letter ω, is defined as the rate of change of angular displacement, θ, or the rate of change of the phase of a sinusoidal waveform, or as the rate of change of the argument to the sine function: y = sin = sin = sin d θ d t = ω = 2 π f Angular frequency is measured in radians per second but, for discrete-time signals, can be expressed as radians per sampling interval, a dimensionless quantity.
Angular frequency is larger than regular frequency by a factor of 2π. Spatial frequency is analogous to temporal frequency, but the time axis is replaced by one or more spatial displacement axes. E.g.: y = sin = sin d θ d x = k Wavenumber, k, is the spatial frequency analogue of angular temporal frequency and is measured in radians per meter. In the case of more than one spatial dimension, wavenumber is a vector quantity. For periodic waves in nondispersive media, frequency has an inverse relationship to the wavelength, λ. In dispersive media, the frequency f of a sinusoidal wave is equal to the phase velocity v of the wave divided by the wavelength λ of the wave: f = v λ. In the special case of electromagnetic waves moving through a vacuum v = c, where c is the speed of light in a vacuum, this expression becomes: f = c λ; when waves from a monochrome source travel from one medium to another, their frequency remains the same—only their wavelength and speed change. Measurement of frequency can done in the following ways, Calculating the frequency of a repeating event is accomplished by counting the number of times that event occurs within a specific time period dividing the count by the length of the time period.
For example, if 71 events occur within 15 seconds the frequency is: f = 71 15 s ≈ 4.73 Hz If the number of counts is not large, it is more accurate to measure the time interval for a predetermined number of occurrences, rather than the number of occurrences within a specified time. The latter method introduces a random error into the count of between zero and one count, so on average half a count; this is called gating error and causes an average error in the calculated frequency of Δ f = 1 2 T
In electric power distribution, a busbar is a metallic strip or bar housed inside switchgear, panel boards, busway enclosures for local high current power distribution. They are used to connect high voltage equipment at electrical switchyards, low voltage equipment in battery banks, they are uninsulated, have sufficient stiffness to be supported in air by insulated pillars. These features allow sufficient cooling of the conductors, the ability to tap in at various points without creating a new joint; the term busbar is derived from the Latin word omnibus, which translates into English as "for all", indicating that a busbar carries all of the currents in a particular system. The material composition and cross-sectional size of the busbar determine the maximum amount of current that can be safely carried. Busbars can have a cross-sectional area of as little as 10 square millimetres, but electrical substations may use metal tubes 50 millimetres in diameter or more as busbars. An aluminium smelter will have large busbars used to carry tens of thousands of amperes to the electrochemical cells that produce aluminium from molten salts.
Busbars are produced in a variety of shapes, such as flat strips, solid bars, or rods, are composed of copper, brass, or aluminium as solid or hollow tubes. Some of these shapes allow heat to dissipate more efficiently due to their high surface area to cross-sectional area ratio; the skin effect makes 50–60 Hz AC busbars more than about 8 millimetres thickness inefficient, so hollow or flat shapes are prevalent in higher current applications. A hollow section has higher stiffness than a solid rod of equivalent current-carrying capacity, which allows a greater span between busbar supports in outdoor electrical switchyards. A busbar must be sufficiently rigid to support its own weight, forces imposed by mechanical vibration and earthquakes, as well as accumulated precipitation in outdoor exposures. In addition, thermal expansion from temperature changes induced by ohmic heating and ambient temperature variations, as well as magnetic forces induced by large currents, must be considered. In order to address these concerns, flexible bus bars a sandwich of thin conductor layers, were developed.
These require a structural cabinet for their installation. Distribution boards split the electrical supply into separate circuits at one location. Busways, or bus ducts, are long busbars with a protective cover. Rather than branching from the main supply at one location, they allow new circuits to branch off anywhere along the route of the busway. A busbar may either be supported on insulators, or else insulation may surround it. Busbars are protected from accidental contact either by a metal earthed enclosure or by elevation out of normal reach. Power neutral busbars may be insulated because it is not guaranteed that the potential between power neutral and safety grounding is always zero. Earthing busbars are bare and bolted directly onto any metal chassis of their enclosure. Busbars may be enclosed in a metal housing, in the form of bus duct or busway, segregated-phase bus, or isolated-phase bus. Busbars may be connected to each other and to electrical apparatus by bolted, clamped, or welded connections.
Joints between high-current bus sections have precisely-machined matching surfaces that are silver-plated to reduce the contact resistance. At extra high voltages in outdoor buses, corona discharge around the connections becomes a source of radio-frequency interference and power loss, so special connection fittings designed for these voltages are used. 110 kV busbars in electrical substations Electrical busbar system Bus Bus duct Walter A. Elmore. Protective Relaying Theory and Applications. Marcel Dekker Inc. ISBN 978-0-8247-9152-0. Paschal, John. "Ensuring a Good Bus Duct Installation". Electrical Construction & Maintenance. Retrieved 2009-04-06. ·Assessment Of Bus Duct And Their Relevance·
A gas turbine called a combustion turbine, is a type of continuous combustion, internal combustion engine. There are three main components: An upstream rotating gas compressor. Above. A fourth component is used to increase efficiency, to convert power into mechanical or electric form, or to achieve greater power to mass/volume ratio; the basic operation of the gas turbine is a Brayton cycle with air as the working fluid. Fresh atmospheric air flows through the compressor. Energy is added by spraying fuel into the air and igniting it so the combustion generates a high-temperature flow; this high-temperature high-pressure gas enters a turbine, where it expands down to the exhaust pressure, producing a shaft work output in the process. The turbine shaft work is used to drive the compressor; the purpose of the gas turbine determines the design so that the most desirable split of energy between the thrust and the shaft work is achieved. The fourth step of the Brayton cycle is omitted, as gas turbines are open systems that do not use the same air again.
Gas turbines are used to power aircraft, ships, electrical generators, gas compressors, tanks. 50: Earliest records of Hero's engine. It most served no practical purpose, was rather more of a curiosity. 1000: The "Trotting Horse Lamp" was used by the Chinese at lantern fairs as early as the Northern Song dynasty. When the lamp is lit, the heated airflow rises and drives an impeller with horse-riding figures attached on it, whose shadows are projected onto the outer screen of the lantern. 1500: The Chimney Jack was drawn by Leonardo da Vinci: Hot air from a fire rises through a single-stage axial turbine rotor mounted in the exhaust duct of the fireplace and turning the roasting spit by gear-chain connection. 1629: Jets of steam rotated an impulse turbine that drove a working stamping mill by means of a bevel gear, developed by Giovanni Branca. 1678: Ferdinand Verbiest built a model carriage relying on a steam jet for power. 1791: A patent was given to John Barber, an Englishman, for the first true gas turbine.
His invention had most of the elements present in the modern day gas turbines. The turbine was designed to power a horseless carriage. 1861: British patent no. 1633 was granted to Marc Antoine Francois Mennons for a "Caloric engine". The patent shows that it was a gas turbine and the drawings show it applied to a locomotive. Named in the patent was Nicolas de Telescheff, a Russian aviation pioneer. 1872: A gas turbine engine designed by Berlin engineer, Franz Stolze, is thought to be the first attempt at creating a working model, but the engine never ran under its own power. 1894: Sir Charles Parsons patented the idea of propelling a ship with a steam turbine, built a demonstration vessel, the Turbinia the fastest vessel afloat at the time. This principle of propulsion is still of some use. 1895: Three 4-ton 100 kW Parsons radial flow generators were installed in Cambridge Power Station, used to power the first electric street lighting scheme in the city. 1899: Charles Gordon Curtis patented the first gas turbine engine in the US.
1900: Sanford Alexander Moss submitted a thesis on gas turbines. In 1903, Moss became an engineer for General Electric's Steam Turbine Department in Lynn, Massachusetts. While there, he applied some of his concepts in the development of the turbosupercharger, his design used a small turbine wheel, driven by exhaust gases. 1903: A Norwegian, Ægidius Elling, built the first gas turbine, able to produce more power than needed to run its own components, considered an achievement in a time when knowledge about aerodynamics was limited. Using rotary compressors and turbines it produced 11 hp. 1906: The Armengaud-Lemale turbine engine in France with a water-cooled combustion chamber. 1910: Holzwarth impulse turbine achieved 150 kilowatts. 1913: Nikola Tesla patents the Tesla turbine based on the boundary layer effect. 1920s The practical theory of gas flow through passages was developed into the more formal theory of gas flow past airfoils by A. A. Griffith resulting in the publishing in 1926 of An Aerodynamic Theory of Turbine Design.
Working testbed designs of axial turbines suitable for driving a propellor were developed by the Royal Aeronautical Establishment proving the efficiency of aerodynamic shaping of the blades in 1929. 1930: Having found no interest from the RAF for his idea, Frank Whittle patented the design for a centrifugal gas turbine for jet propulsion. The first successful use of his engine occurred in England in April 1937. 1932: BBC Brown, Boveri & Cie of Switzerland] starts selling axial compressor and turbine turbosets as part of the turbocharged steam generating Velox boiler. Following the gas turbine principle, the steam evaporation tubes are arranged within the gas turbine combustion chamber. 1934: Raúl Pateras de Pescara patented the free-piston engine as a gas gener
Diesel fuel in general is any liquid fuel used in diesel engines, whose fuel ignition takes place, without any spark, as a result of compression of the inlet air mixture and injection of fuel. Diesel engines have found broad use as a result of higher thermodynamic efficiency and thus fuel efficiency; this is noted where diesel engines are run at part-load. The most common type of diesel fuel is a specific fractional distillate of petroleum fuel oil, but alternatives that are not derived from petroleum, such as biodiesel, biomass to liquid or gas to liquid diesel, are being developed and adopted. To distinguish these types, petroleum-derived diesel is called petrodiesel. Ultra-low-sulfur diesel is a standard for defining diesel fuel with lowered sulfur contents; as of 2016 all of the petroleum-based diesel fuel available in the UK, mainland Europe, North America is of a ULSD type. In the UK, diesel fuel for on-road use is abbreviated DERV, standing for diesel-engined road vehicle, which carries a tax premium over equivalent fuel for non-road use.
In Australia, diesel fuel is known as distillate, in Indonesia, it is known as Solar, a trademarked name by the local oil company Pertamina. Diesel fuel originated from experiments conducted by German scientist and inventor Rudolf Diesel for his compression-ignition engine he invented in 1892. Diesel designed his engine to use coal dust as fuel, experimented with other fuels including vegetable oils, such as peanut oil, used to power the engines which he exhibited at the 1900 Paris Exposition and the 1911 World's Fair in Paris. Diesel fuel is produced from the most common being petroleum. Other sources include biomass, animal fat, natural gas, coal liquefaction. Petroleum diesel called petrodiesel, or fossil diesel is the most common type of diesel fuel, it is produced from the fractional distillation of crude oil between 200 °C and 350 °C at atmospheric pressure, resulting in a mixture of carbon chains that contain between 9 and 25 carbon atoms per molecule. Synthetic diesel can be produced from any carbonaceous material, including biomass, natural gas and many others.
The raw material is gasified into synthesis gas, which after purification is converted by the Fischer–Tropsch process to a synthetic diesel. The process is referred to as biomass-to-liquid, gas-to-liquid or coal-to-liquid, depending on the raw material used. Paraffinic synthetic diesel has a near-zero content of sulfur and low aromatics content, reducing unregulated emissions of toxic hydrocarbons, nitrous oxides and particulate matter. Fatty-acid methyl ester, more known as biodiesel, is obtained from vegetable oil or animal fats which have been transesterified with methanol, it can be produced from many types of oils, the most common being rapeseed oil in Europe and soybean oil in the US. Methanol can be replaced with ethanol for the transesterification process, which results in the production of ethyl esters; the transesterification processes use catalysts, such as sodium or potassium hydroxide, to convert vegetable oil and methanol into FAME and the undesirable byproducts glycerine and water, which will need to be removed from the fuel along with methanol traces.
FAME can be used pure in engines where the manufacturer approves such use, but it is more used as a mix with diesel, BXX where XX is the biodiesel content in percent. FAME as a fuel is specified in DIN EN 14214 and ASTM D6751. Fuel equipment manufacturers have raised several concerns regarding FAME fuels, identifying FAME as being the cause of the following problems: corrosion of fuel injection components, low-pressure fuel system blockage, increased dilution and polymerization of engine sump oil, pump seizures due to high fuel viscosity at low temperature, increased injection pressure, elastomeric seal failures and fuel injector spray blockage. Pure biodiesel has an energy content about 5–10% lower than petroleum diesel; the loss in power when using pure biodiesel is 5–7%. Unsaturated fatty acids are the source for the lower oxidation stability; as FAME contains low levels of sulfur, the emissions of sulfur oxides and sulfates, major components of acid rain, are low. Use of biodiesel results in reductions of unburned hydrocarbons, carbon monoxide, particulate matter.
CO emissions using biodiesel are reduced, on the order of 50% compared to most petrodiesel fuels. The exhaust emissions of particulate matter from biodiesel have been found to be 30% lower than overall particulate matter emissions from petrodiesel; the exhaust emissions of total hydrocarbons are up to 93% lower for biodiesel than diesel fuel. Biodiesel may reduce health risks associated with petroleum diesel. Biodiesel emissions showed decreased levels of polycyclic aromatic hydrocarbon and nitrited PAH compounds, which have been identified as potential cancer-causing compounds. In recent testing, PAH compounds were reduced by 75–85%, except for benzanthracene, reduced by 50%. Targeted nPAH compounds were reduced with biodiesel fuel, with 2-nitrofluorene and 1-nitropyrene reduced by 90%, the rest
A power station referred to as a power plant or powerhouse and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Most power stations contain one or more generators, a rotating machine that converts mechanical power into electrical power; the relative motion between a magnetic field and a conductor creates an electrical current. The energy source harnessed to turn the generator varies widely. Most power stations in the world burn fossil fuels such as coal and natural gas to generate electricity. Others use nuclear power, but there is an increasing use of cleaner renewable sources such as solar, wind and hydroelectric. In 1878 a hydroelectric power station was built by Lord Armstrong at Cragside, England, it used water from lakes on his estate to power Siemens dynamos. The electricity supplied power to lights, produced hot water, ran an elevator as well as labor-saving devices and farm buildings. In the early 1870s Belgian inventor Zénobe Gramme invented a generator powerful enough to produce power on a commercial scale for industry.
In the autumn of 1882, a central station providing public power was built in England. It was proposed after the town failed to reach an agreement on the rate charged by the gas company, so the town council decided to use electricity, it used hydroelectric power for household lighting. The system was not the town reverted to gas. In 1882 the world's first coal-fired public power station, the Edison Electric Light Station, was built in London, a project of Thomas Edison organized by Edward Johnson. A Babcock & Wilcox boiler powered a 125-horsepower steam engine; this supplied electricity to premises in the area that could be reached through the culverts of the viaduct without digging up the road, the monopoly of the gas companies. The customers included the Old Bailey. Another important customer was the Telegraph Office of the General Post Office, but this could not be reached though the culverts. Johnson arranged for the supply cable to be run overhead, via Holborn Newgate. In September 1882 in New York, the Pearl Street Station was established by Edison to provide electric lighting in the lower Manhattan Island area.
The station ran until destroyed by fire in 1890. The station used reciprocating steam engines to turn direct-current generators; because of the DC distribution, the service area was small. In 1886 George Westinghouse began building an alternating current system that used a transformer to step up voltage for long-distance transmission and stepped it back down for indoor lighting, a more efficient and less expensive system, similar to modern system; the War of Currents resolved in favor of AC distribution and utilization, although some DC systems persisted to the end of the 20th century. DC systems with a service radius of a mile or so were smaller, less efficient of fuel consumption, more labor-intensive to operate than much larger central AC generating stations. AC systems used a wide range of frequencies depending on the type of load; the economics of central station generation improved when unified light and power systems, operating at a common frequency, were developed. The same generating plant that fed large industrial loads during the day, could feed commuter railway systems during rush hour and serve lighting load in the evening, thus improving the system load factor and reducing the cost of electrical energy overall.
Many exceptions existed, generating stations were dedicated to power or light by the choice of frequency, rotating frequency changers and rotating converters were common to feed electric railway systems from the general lighting and power network. Throughout the first few decades of the 20th century central stations became larger, using higher steam pressures to provide greater efficiency, relying on interconnections of multiple generating stations to improve reliability and cost. High-voltage AC transmission allowed hydroelectric power to be conveniently moved from distant waterfalls to city markets; the advent of the steam turbine in central station service, around 1906, allowed great expansion of generating capacity. Generators were no longer limited by the power transmission of belts or the slow speed of reciprocating engines, could grow to enormous sizes. For example, Sebastian Ziani de Ferranti planned what would have been the largest reciprocating steam engine built for a proposed new central station, but scrapped the plans when turbines became available in the necessary size.
Building power systems out of central stations required combinations of engineering skill and financial acumen in equal measure. Pioneers of central station generation include George Westinghouse and Samuel Insull in the United States and Charles Hesterman Merz in UK, many others. In thermal power stations, mechanical power is produced by a heat engine that transforms thermal energy from combustion of a fuel, into rotational energy. Most thermal power stations produce steam, so they are sometimes called steam power stations. Not all thermal energy can be transformed into mechanical power, according to the second law of thermodynamics. If this loss is employed as useful heat, for industrial processes or district heating, the power plant is referred to as a cogeneration power plant or CHP plant. In countries where district heating is common, there are dedicated he
A fuel cell is an electrochemical cell that converts the chemical energy of a fuel and an oxidizing agent into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen to sustain the chemical reaction, whereas in a battery the chemical energy comes from metals and their ions or oxides that are already present in the battery, except in flow batteries. Fuel cells can produce electricity continuously for as long as oxygen are supplied; the first fuel cells were invented in 1838. The first commercial use of fuel cells came more than a century in NASA space programs to generate power for satellites and space capsules. Since fuel cells have been used in many other applications. Fuel cells are used for primary and backup power for commercial and residential buildings and in remote or inaccessible areas, they are used to power fuel cell vehicles, including forklifts, buses, boats and submarines. There are many types of fuel cells, but they all consist of an anode, a cathode, an electrolyte that allows ions positively charged hydrogen ions, to move between the two sides of the fuel cell.
At the anode a catalyst causes the fuel to undergo oxidation reactions that generate ions and electrons. The ions move from the anode to the cathode through the electrolyte. At the same time, electrons flow from the anode to the cathode through an external circuit, producing direct current electricity. At the cathode, another catalyst causes ions and oxygen to react, forming water and other products. Fuel cells are classified by the type of electrolyte they use and by the difference in startup time ranging from 1 second for proton exchange membrane fuel cells to 10 minutes for solid oxide fuel cells. A related technology is flow batteries. Individual fuel cells produce small electrical potentials, about 0.7 volts, so cells are "stacked", or placed in series, to create sufficient voltage to meet an application's requirements. In addition to electricity, fuel cells produce water, heat and, depending on the fuel source small amounts of nitrogen dioxide and other emissions; the energy efficiency of a fuel cell is between 40–60%.
The fuel cell market is growing, in 2013 Pike Research estimated that the stationary fuel cell market will reach 50 GW by 2020. The first references to hydrogen fuel cells appeared in 1838. In a letter dated October 1838 but published in the December 1838 edition of The London and Edinburgh Philosophical Magazine and Journal of Science, Welsh physicist and barrister William Grove wrote about the development of his first crude fuel cells, he used a combination of sheet iron and porcelain plates, a solution of sulphate of copper and dilute acid. In a letter to the same publication written in December 1838 but published in June 1839, German physicist Christian Friedrich Schönbein discussed the first crude fuel cell that he had invented, his letter discussed current generated from oxygen dissolved in water. Grove sketched his design, in 1842, in the same journal; the fuel cell he made used similar materials to today's phosphoric-acid fuel cell. In 1939, British engineer Francis Thomas Bacon developed a 5 kW stationary fuel cell.
In 1955, W. Thomas Grubb, a chemist working for the General Electric Company, further modified the original fuel cell design by using a sulphonated polystyrene ion-exchange membrane as the electrolyte. Three years another GE chemist, Leonard Niedrach, devised a way of depositing platinum onto the membrane, which served as catalyst for the necessary hydrogen oxidation and oxygen reduction reactions; this became known as the "Grubb-Niedrach fuel cell". GE went on to develop this technology with NASA and McDonnell Aircraft, leading to its use during Project Gemini; this was the first commercial use of a fuel cell. In 1959, a team led by Harry Ihrig built a 15 kW fuel cell tractor for Allis-Chalmers, demonstrated across the U. S. at state fairs. This system used potassium hydroxide as the electrolyte and compressed hydrogen and oxygen as the reactants. In 1959, Bacon and his colleagues demonstrated a practical five-kilowatt unit capable of powering a welding machine. In the 1960s, Pratt and Whitney licensed Bacon's U.
S. patents for use in the U. S. space program to supply drinking water. In 1991, the first hydrogen fuel cell automobile was developed by Roger Billings. UTC Power was the first company to manufacture and commercialize a large, stationary fuel cell system for use as a co-generation power plant in hospitals and large office buildings. In recognition of the fuel cell industry and America’s role in fuel cell development, the US Senate recognized 8 October 2015 as National Hydrogen and Fuel Cell Day, passing S. RES 217; the date was chosen in recognition of the atomic weight of hydrogen. Fuel cells come in many varieties, they are made up of three adjacent segments: the anode, the electrolyte, the cathode. Two chemical reactions occur at the interfaces of the three different segments; the net result of the two reactions is that fuel is consumed, water or carbon dioxide is created, an electric current is created, which can be used to power electrical devices referred to as the load. At the anode a catalyst oxidizes