"Electric power Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries. It is usually supplied to businesses and homes (as domestic mains electricity) by the electric power industry through an electric power grid. Electric power is usually sold by the kilowatt hour (3.6 MJ) which is the product of the power in kilowatts multiplied by running time in hours. Electric"
"a sustained power of about 114 megawatts for a period of one year. The symbol ""kWh"" is commonly used in commercial, educational, scientific and media publications, and is the usual practice in electrical power engineering. Other abbreviations and symbols may be encountered: To convert a quantity measured in a unit in the left column to the units in the top row, multiply by the factor in the cell where the row and column intersect. All the SI prefixes are commonly applied to the watt hour: a kilowatt hour is 1,000 W⋅h (symbols kW⋅h, kWh or kW h; a megawatt hour"
"watt is equal to 1 J/s. One kilowatt hour is 3.6 megajoules, which is the amount of energy converted if work is done at an average rate of one thousand watts for one hour. The derived unit of energy within the International System of Units (SI) is the joule. The hour is a unit of time ""outside the SI"", making the kilowatt hour a non-SI unit of energy. The kilowatt hour is not listed among the non-SI units accepted by the BIPM for use with the SI, although the hour, from which the kilowatt hour is derived, is. An electric"
"express the annual electricity generation for whole countries and the world energy consumption. Petawatt hours can describe the output of nuclear power plants across decades. For example, the Gravelines Nuclear Power Station in France became in 2010 the first power plant to ever deliver a cumulative petawatt-hour of electricity. The terms power and energy are frequently confused. Power is the rate of delivery of energy. Power is work performed per unit of time. Energy is the work performed (over a period of time). Power is measured using the unit ""watts"", or ""joules per second"". Energy is measured using the unit"
"in ""true"" watt-seconds, and some specify their products in ""nominal"" watt-seconds. Joule The joule (; symbol: J) is a derived unit of energy in the International System of Units. It is equal to the energy transferred to (or work done on) an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre (1 newton metre or N⋅m). It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the"
"changes at a rate of one ampere per second. The inductor's behaviour is in some regards converse to that of the capacitor: it will freely allow an unchanging current, but opposes a rapidly changing one. Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Electric power, like mechanical power, is the rate of doing work, measured in watts, and represented by the letter ""P"". The term ""wattage"" is used colloquially to mean ""electric power in watts."" The electric power in watts produced"
"Kilowatt hour The kilowatt hour (symbol kWh, kW⋅h or kW h) is a unit of energy equal to 3.6 megajoules. If energy is transmitted or used at a constant rate (power) over a period of time, the total energy in kilowatt hours is equal to the power in kilowatts multiplied by the time in hours. The kilowatt hour is commonly used as a billing unit for energy delivered to consumers by electric utilities. The kilowatt hour (symbolized kW⋅h as per SI) is a composite unit of energy equivalent to one kilowatt (1 kW) of power sustained for one hour. One"
"to refine his initial large and heavy design, although he did also develop a polyphase version. The most common unit of measurement on the electricity meter is the kilowatt hour [""kWh""], which is equal to the amount of energy used by a load of one kilowatt over a period of one hour, or 3,600,000 joules. Some electricity companies use the SI megajoule instead. Demand is normally measured in watts, but averaged over a period, most often a quarter- or half-hour. Reactive power is measured in ""thousands of volt-ampere reactive-hours"", (kvarh). By convention, a ""lagging"" or inductive load, such as a"
"energy, a higher level of power causes that energy to be used in less time. Power units measure the rate of energy per unit time. Many compound units for rates explicitly mention units of time, for example, miles per hour, kilometers per hour, dollars per hour. Kilowatt hours are a product of power and time, not a rate of change of power with time. Watts per hour (W/h) is a unit of a ""change"" of power per hour. It might be used to characterize the ramp-up behavior of power plants. For example, a power plant that reaches a power output"
"when a light bulb with a power rating of is turned on for one hour, the energy used is 100 watt hours (W·h), 0.1 kilowatt hour, or 360 kJ. This same amount of energy would light a 40-watt bulb for 2.5 hours, or a 50-watt bulb for 2 hours. Power stations are rated using units of power, typically megawatts or gigawatts (for example, the Three Gorges Dam is rated at approximately 22 gigawatts). This reflects the maximum power output it can achieve at any point in time. A power station's annual energy output, however, would be recorded using units of"
"There are no U.S. customary units for electric current, potential difference, or charge since these concepts were developed after the international adoption of metric in science. The metric units ampere, volt, ohm and coulomb are the only units used. The SI term hertz has replaced the term ""cycles per second"" as a unit of frequency. Energy is often measured in watt hours, BTUs, therms or calories rather than the SI joule. Residential and commercial electrical energy use is metered and billed in kilowatt hours, kW·h, as in most metric countries. Force measurements regularly use the pound instead of the SI"
"of 1 MW from 0 MW in 15 minutes has a ramp-up rate of 4 MW/h. Hydroelectric power plants have a very high ramp-up rate, which makes them particularly useful in peak load and emergency situations. The proper use of terms such as ""watts per hour"" is uncommon, whereas misuse may be widespread. By definition of the units, a consumption of 1 kWh/100 km is exactly equivalent to a resistance force of 36 N (newtons), an idea taken up by the von Kármán–Gabrielli diagram. Several other units are commonly used to indicate power or energy capacity or use in specific"
"one joule of energy per coulomb of charge that passes through it. It can be expressed in terms of SI base units (m, kg, s, and A) as It can also be expressed as amperes times ohms (current times resistance, Ohm's law), watts per ampere (power per unit current, definition of electric power), or joules per coulomb (energy per unit charge), which is also equivalent to electronvolts per elementary charge: The ""conventional"" volt, V, defined in 1988 by the 18th General Conference on Weights and Measures and in use from 1990, is implemented using the Josephson effect for exact frequency-to-voltage"
"the ""international"" watt was redefined from practical units to absolute units (i.e., using only length, mass, and time). Concretely, this meant that 1 watt was now defined as the quantity of energy transferred in a unit of time, namely 1 J/s. In this new definition, 1 ""absolute"" watt = 1.00019 ""international"" watts. Texts written before 1948 are likely to be using the ""international"" watt, which implies caution when comparing numerical values from this period with the post-1948 watt. In 1960 the 11th General Conference on Weights and Measures adopted the ""absolute"" ""watt"" into the International System of Units (SI) as"
"application areas. Average annual power production or consumption can be expressed in kilowatt hours per year; for example, when comparing the energy efficiency of household appliances whose power consumption varies with time or the season of the year, or the energy produced by a distributed power source. One kilowatt hour per year equals about 114.08 milliwatts applied constantly during one year. The energy content of a battery is usually expressed indirectly by its capacity in ampere-hours; to convert ampere-hour (A⋅h) to watt hours (W⋅h), the ampere-hour value must be multiplied by the voltage of the power source. This value is"
"UK synonym for kilowatt hour. The term derives from the name of the Board of Trade which regulated the electricity industry until 1942 when the Ministry of Power took over. The British thermal unit or BTU (not to be confused with BOTU), is a unit of thermal energy with several definitions, all about 1055 Joule or 0.293 watt hour. The quad, short for quadrillion BTU, or 10 BTU, is sometimes used in national-scale energy discussions in the United States. One quad is approximately 293 TWh or 1.055 exajoule (EJ). A TNT equivalent is a measure of energy released in the"
"unit used for everyday electricity, particularly for utility bills, is the kilowatt-hour (kWh); one kWh is equivalent to 3.6×10 J (3600 kJ or 3.6 MJ). Electricity usage is often given in units of kilowatt-hours per year (kWh/yr). This is actually a measurement of average power consumption, i.e., the average rate at which energy is transferred. One kWh/yr is about 0.11 watts. Natural gas in the US is sold in Therms or 100 cubic feet (100 ft = 1 Ccf). One Therm is equal to about 105.5 megajoules. In Australia, natural gas is sold in megajoules. In the most of the"
"is 1 million W⋅h, (symbols MW⋅h, MWh or MW h); a milliwatt hour is 1/1000 W⋅h (symbols mW⋅h, mWh or mW h) and so on. The kilowatt hour is commonly used by electrical distribution providers for purposes of billing, since the monthly energy consumption of a typical residential customer ranges from a few hundred to a few thousand kilowatt hours. Megawatt hours (MWh), gigawatt hours (GWh), and terawatt hours (TWh) are often used for metering larger amounts of electrical energy to industrial customers and in power generation. The terawatt hour and petawatt hour (PWh) units are large enough to conveniently"
"One Watt Initiative The One Watt Initiative (or the proper One-Watt Initiative) is an energy-saving initiative by the International Energy Agency (IEA) to reduce standby power-use by any appliance to not more than one watt in 2010, and 0.5 watts in 2013, which has given rise to regulations in many countries and regions. Standby power, informally called ""vampire"" or ""phantom power,"" refers to the electricity consumed by many appliances when they are switched off or in standby mode. The typical standby power per appliance is low (typically from less than 1 to 25 W), but, when multiplied by the billions"
"within the then-existing system of practical units as ""the power conveyed by a current of an Ampère through the difference of potential of a Volt."" In October 1908, at the International Conference on Electric Units and Standards in London, so-called ""international"" definitions were established for practical electrical units. Siemens' definition was adopted as the ""international"" watt. (Also used: 1 ampere x 1 ohm.) The watt was defined as equal to 10 units of power in the ""practical system"" of units. The ""international units"" were dominant from 1909 until 1948. After the 9th General Conference on Weights and Measures in 1948,"
"(on average) at 80 watts, then a light bulb running at 100 watts is running at 1.25 human equivalents (100 ÷ 80) i.e. 1.25 H-e. For a difficult task of only a few seconds' duration, a person can put out thousands of watts, many times the 746 watts in one official horsepower. For tasks lasting a few minutes, a fit human can generate perhaps 1,000 watts. For an activity that must be sustained for an hour, output drops to around 300; for an activity kept up all day, 150 watts is about the maximum. The human equivalent assists understanding of"
"Ampere hour An ampere hour or amp hour (symbol Ah; also denoted A⋅h or A h) is a unit of electric charge, having dimensions of electric current multiplied by time, equal to the charge transferred by a steady current of one ampere flowing for one hour, or 3600 coulombs. The commonly seen ""milliampere hour"" (mAh or mA⋅h) is one-thousandth of an ampere hour (3.6 coulombs). The ampere hour is frequently used in measurements of electrochemical systems such as electroplating and for battery capacity where the commonly known nominal voltage is dropped. A ""milliampere second"" (mA⋅s) is a unit of measure"
"is still widely used in astrophysics and sometimes in mechanics. Erg The erg is a unit of energy and work equal to 10 joules. It originated in the centimetre–gram–second (CGS) system of units. It has the symbol ""erg"". The erg is not an SI unit. Its name is derived from ""ergon"" (ἔργον), a Greek word meaning ""work"" or ""task"". An erg is the amount of work done by a force of one dyne exerted for a distance of one centimeter. In the CGS base units, it is equal to one gram centimeter-squared per second-squared (g·cm/s). It is thus equal to"
"and megawatt refers to the entire thermal output, not the fraction which is converted to electricity. Kilowatt hour The kilowatt hour (symbol kWh, kW⋅h or kW h) is a unit of energy equal to 3.6 megajoules. If energy is transmitted or used at a constant rate (power) over a period of time, the total energy in kilowatt hours is equal to the power in kilowatts multiplied by the time in hours. The kilowatt hour is commonly used as a billing unit for energy delivered to consumers by electric utilities. The kilowatt hour (symbolized kW⋅h as per SI) is a composite"
"energy since energy is inversely proportional to wavelength from the equation formula_2. In discussions of energy production and consumption, the units barrel of oil equivalent and ton of oil equivalent are often used. When discussing amounts of energy released in explosions or bolide impact events, the TNT equivalent unit is often used. The British Imperial units and U.S. Customary units for both energy and work include the foot-pound force (1.3558 J), the British thermal unit (BTU) which has various values in the region of 1055 J, the horsepower-hour (2.6845 MJ), and the gasoline gallon equivalent (about 120 MJ). The energy"
"heater consuming 1000 watts (1 kilowatt), and operating for one hour uses one kilowatt hour of energy. A television consuming 100 watts operating for 10 hours continuously uses one kilowatt hour. A 40-watt electric appliance operating continuously for 25 hours uses one kilowatt hour. In terms of human power, a healthy adult male manual laborer will perform work equal to about half a kilowatt hour over an eight-hour day. Electrical energy is typically sold to consumers in kilowatt hours. The cost of running an electric device is calculated by multiplying the device's power consumption in kilowatts by the running time"
"work done or energy converted per unit of time. The average power is often simply called ""power"" when the context makes it clear. The instantaneous power is then the limiting value of the average power as the time interval Δ""t"" approaches zero. In the case of constant power ""P"", the amount of work performed during a period of duration ""T"" is given by: In the context of energy conversion, it is more customary to use the symbol ""E"" rather than ""W"". Power in mechanical systems is the combination of forces and movement. In particular, power is the product of a"
"second"" is in calculation of the power transmitted by a shaft. In the International System of Units, widely used in physics and engineering, the power ""p"" is equal to the rotational speed ""ω"" (in radians per second) multiplied by the torque ""τ"" applied to the shaft, in newton-meters. Thus, , and the unit is the watt, with no numerical coefficient needed. In other systems, an additional factor may be necessary. For example, if one multiplies angular velocity in revolutions per minute (rpm) by the torque in pound-feet, then a factor is needed to convert the result in horsepower. An angular"
"make it easier to judge the effect of an improvement in energy efficiency. Performance (in operations/second) per watt can also be written as operations/watt-second, or operations/joule, since 1 watt = 1 joule/second. FLOPS per watt is a common measure. Like the FLOPS (Floating Point Operations Per Second) metric it is based on, the metric is usually applied to scientific computing and simulations involving many floating point calculations. , the Green500 list rates the two most efficient supercomputers highest those are both based on the same manycore accelerator PEZY-SCnp Japanese technology in addition to Intel Xeon processors both at RIKEN, the"
"It takes around 3 kWh of heat to produce 1 kWh of electricity. But by the same token, a kilowatt-hour of this high-quality electricity can be used to pump several kilowatt-hours of heat into a building using a heat pump. And electricity can be used in many ways in which heat cannot. So the ""loss"" of energy incurred when generating electricity is not the same as a loss due, say, to resistance in power lines In 2014, world primary energy supply amounted to 155,481 terawatt-hour (TWh) or 13,541 Mtoe, while the world final energy consumption was 109,613 TWh or about"
"(V). Two additional unit conversions for watt can be found using the above equation and Ohm's Law. Where ohm (formula_4) is the SI derived unit of electrical resistance. The ""watt"" is named after the Scottish inventor James Watt. This unit was proposed initially by C. William Siemens in August 1882 in his President's Address to the Fifty-Second Congress of the British Association for the Advancement of Science. Noting that units in the practical system of units were named after leading physicists, Siemens proposed that ""Watt"" might be an appropriate name for a unit of power. Siemens defined the unit consistently"
"customary unit is the foot pound. Other energy units such as the electronvolt, food calorie or thermodynamic kcal (based on the temperature change of water in a heating process), and BTU are used in specific areas of science and commerce. In classical mechanics, energy is a conceptually and mathematically useful property, as it is a conserved quantity. Several formulations of mechanics have been developed using energy as a core concept. Work, a function of energy, is force times distance. This says that the work (formula_2) is equal to the line integral of the force F along a path ""C""; for"
"Joule-second The joule-second (J s, or J∙s) is the mathematical product of an SI Derived Unit, the joule (J), and an SI Base Unit, the second (s). The joule-second describes the amount of action occurring in a physical system through a summation of energy (or heat, or work) over time. In mathematical terms, this summation of energy means that the quantity of energy becomes integrated over time to give a number - an answer to the question. In SI base units the joule-second becomes kilogram-meters squared-per second or kg∙m∙ s. Dimensional Analysis of the joule-second yields M L T. Note"