Declared net capacity (DNC) is a measure of the contribution that a power station makes to the overall capacity of a distribution grid. It is measured in megawatts (MW), or in megawatts electrical (MWe) for a thermal power station.
A power station, also 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, oil, and natural gas to generate electricity. Others use nuclear power, but there is an increasing use of cleaner renewable sources such as solar, wind, wave and hydroelectric.
DNC is sometimes expanded as developed net capacity in British English; The two expansions have exactly the same meaning.
British English is the standard dialect of English language as spoken and written in the United Kingdom. Variations exist in formal, written English in the United Kingdom. For example, the adjective wee is almost exclusively used in parts of Scotland and Ireland, and occasionally Yorkshire, whereas little is predominant elsewhere. Nevertheless, there is a meaningful degree of uniformity in written English within the United Kingdom, and this could be described by the term British English. The forms of spoken English, however, vary considerably more than in most other areas of the world where English is spoken, so a uniform concept of British English is more difficult to apply to the spoken language. According to Tom McArthur in the Oxford Guide to World English, British English shares "all the ambiguities and tensions in the word 'British' and as a result can be used and interpreted in two ways, more broadly or more narrowly, within a range of blurring and ambiguity".
In a conventional power station, the DNC rating is simply the maximum rated output minus the power consumed onsite. It is sometimes termed the switchyard output, and takes no account of transmission losses in the grid, which may be considerable in the case of a remote hydro station for example. Most but not all quoted power station ratings are DNC ratings rather than the simple capacity of the alternators.
An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature. Occasionally, a linear alternator or a rotating armature with a stationary magnetic field is used. In principle, any AC electrical generator can be called an alternator, but usually the term refers to small rotating machines driven by automotive and other internal combustion engines. An alternator that uses a permanent magnet for its magnetic field is called a magneto. Alternators in power stations driven by steam turbines are called turbo-alternators. Large 50 or 60 Hz three-phase alternators in power plants generate most of the world's electric power, which is distributed by electric power grids.
In the case of a wind power station, the situation is more complex. The alternator of a wind turbine is normally specified to match the strongest wind in which the turbine is designed to operate. This is because most of the cost of a wind turbine is in the rotor and the tower and bearings that support it, rather than in the alternator. It makes no economic sense to restrict the size of the alternator to anything less than the maximum that the rotor will deliver. However, this means that, unlike a conventional power station, a wind turbine rarely achieves its maximum rated output while operating.
Wind power is the use of air flow through wind turbines to provide the mechanical power to turn electric generators. Wind power, as an alternative to burning fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation, consumes no water, and uses little land. The net effects on the environment are far less problematic than those of fossil fuel sources.
A wind turbine, or alternatively referred to as a wind energy converter, is a device that converts the wind's kinetic energy into electrical energy.
While for conventional power stations, the station is only regarded as available if the full power output is achievable, for wind power stations no power at all may be available depending on the wind strength, and even if a turbine is operating it may be producing as little as a tenth of its maximum rated capacity. A typical average figure is between one-third and one-half of the maximum rated capacity.
There are several suggested methods of allowing for this when quoting a DNC figure for a wind farm, but none has gained general acceptance, and the capacity quoted for a wind farm is normally a simple total of the maximum rated capacities of the turbines, sometimes termed the peak capacity. Many wind schemes now also quote their expected or actual annual output in GWh, to allow more meaningful comparisons with other forms of generation than is possible just by considering this total rated output.
A wind farm or wind park is a group of wind turbines in the same location used to produce electricity. A large wind farm may consist of several hundred individual wind turbines and cover an extended area of hundreds of square miles, but the land between the turbines may be used for agricultural or other purposes. A wind farm can also be located offshore.
Another article at the DTI site, using DNC for developed net capacity.
The Department of Trade and Industry (DTI) was a United Kingdom government department formed on 19 October 1970. It was replaced with the creation of the Department for Business, Enterprise and Regulatory Reform and the Department for Innovation, Universities and Skills on 28 June 2007.
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In electricity generation, a generator is a device that converts motive power into electrical power for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, internal combustion engines and even hand cranks. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday. Generators provide nearly all of the power for electric power grids.
Peaking power plants, also known as peaker plants, and occasionally just "peakers", are power plants that generally run only when there is a high demand, known as peak demand, for electricity. Because they supply power only occasionally, the power supplied commands a much higher price per kilowatt hour than base load power. Peak load power plants are dispatched in combination with base load power plants, which supply a dependable and consistent amount of electricity, to meet the minimum demand.
A diesel generator is the combination of a diesel engine with an electric generator to generate electrical energy. This is a specific case of engine-generator. A diesel compression-ignition engine is usually designed to run on diesel fuel, but some types are adapted for other liquid fuels or natural gas.
The net capacity factor is the unitless ratio of an actual electrical energy output over a given period of time to the maximum possible electrical energy output over that period. The capacity factor is defined for any electricity producing installation, such as a fuel consuming power plant or one using renewable energy, such as wind or the sun. The average capacity factor can also be defined for any class of such installations, and can be used to compare different types of electricity production.
Doubly-fed electric machines also slip-ring generators are electric motors or electric generators, where both the field magnet windings and armature windings are separately connected to equipment outside the machine.
Wind turbine design is the process of defining the form and specifications of a wind turbine to extract energy from the wind.
A wind turbine installation consists of the necessary systems needed to capture the wind's energy, point the turbine into the wind, convert mechanical rotation into electrical power, and other systems to start, stop, and control the turbine.
An induction generator or asynchronous generator is a type of alternating current (AC) electrical generator that uses the principles of induction motors to produce power. Induction generators operate by mechanically turning their rotors faster than synchronous speed. A regular AC induction motor usually can be used as a generator, without any internal modifications. Induction generators are useful in applications such as mini hydro power plants, wind turbines, or in reducing high-pressure gas streams to lower pressure, because they can recover energy with relatively simple controls.
Wind power in Germany is a growing industry. The installed capacity was 55.6 gigawatt (GW) at the end of 2017, with 5.2 GW from offshore installations.
The wind power share of the country's total electricity generation was estimated at 9.3% in 2010, 10.6% in 2011, 13.3% in 2015, and 18.7% in 2017.
As of 2017, the Republic of Ireland has 2,878 megawatt of installed wind power nameplate capacity.
In 2015 wind turbines generated 23% of Ireland's average electricity demand, one of the highest wind power penetration in the world.
Ireland's 226 wind farms, are almost exclusively onshore, with only the 25 MW Arklow Bank Wind Park situated offshore as of 2017.
Kingsnorth was a dual-fired coal and oil power station on the Hoo Peninsula at Medway in Kent, South East England. The four-unit station was operated by energy firm E.ON UK, and had a generating capacity of 2000 megawatts. It was capable of operating on either coal or oil though in practice oil was used only as a secondary fuel or for startup. It was also capable of co-firing biofuel, up to a maximum of 10% of the station's fuel mix. A replacement power station, also coal-fired, was considered by owners E.ON, but plans were abandoned. The proposed replacement attracted substantial public protests and criticism, including the 2008 Camp for Climate Action.
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Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, or maximum effect, is the intended full-load sustained output of a facility such as a power plant, electric generator, a chemical plant, fuel plant, metal refinery, mine, and many others. Nameplate capacity is the number registered with authorities for classifying the power output of a power station usually expressed in megawatts (MW).
Coopers Gap Wind Farm is a 500-megawatt (671,000 hp) wind power station under construction in the Bilboa and Cooranga North region, of Australia, approximately 50 kilometres (31 mi) south-west of Kingaroy and 65 km (40 mi) north of Dalby in Queensland, Australia.
Starting in 1975, NASA managed a program for the United States Department of Energy and the United States Department of Interior to develop utility-scale wind turbines for electric power, in response to the increase in oil prices.
A number of the world's largest wind turbines were developed and tested under this pioneering program. The program was an attempt to leap well beyond the then-current state of the art of wind turbine generators, and developed a number of technologies later adopted by the wind turbine industry. The development of the commercial industry however was delayed by a significant decrease in competing energy prices during the 1980s.
The Delabole wind farm was the first commercial onshore wind farm built in the United Kingdom, in November 1991. This field of wind turbines was initially developed by Windelectric Management Ltd.
The following outline is provided as an overview of and topical guide to wind energy:
Single-phase generator is an alternating current electrical generator that produces a single, continuously alternating voltage. Single-phase generators can be used to generate power in single-phase electric power systems. However, polyphase generators are generally used to deliver power in three-phase distribution system and the current is converted to single-phase near the single-phase loads instead. Therefore, single-phase generators are found in applications that are most often used when the loads being driven are relatively light, and not connected to a three-phase distribution, for instance, portable engine-generators. Larger single-phase generators are also used in special applications such as single-phase traction power for railway electrification systems.
