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Ratcliffe-on-Soar coal power station occupies a prominent position close to junction 24 of the M1, the River Trent and the Midland Main Line (adjacent to East Midlands Parkway station) and dominates the skyline for many miles around with its eight cooling towers and 199 m (653 ft) tall chimney. It has four coal-fired boilers made by Babcock and Wilcox, each of which drive a 500 megawatt (MW) Parsons generator set. This gives the station a total generating capacity of 2,000 MW, which is enough electricity to meet the needs of approximately 2 million people.
E.ON UK has its Technology Centre at the site, now known as E.ON New Build and Technology, where the it carries out research and development on power generation.
Ratcliffe-on-Soar coal power station emits some 8–10 million tonnes of CO2 annually making it the 18th highest CO2 emitting power station in Europe. Some 48 million cubic meters of Cooling water is taken from the nearby River Trent. Evaporative losses through the eight cooling towers account for some 11 million cubic metres of that water.Ratcliffe power station is compliant with the Large Combustion Plant Directive (LCPD), an EU directive that aims to reduce acidification, ground level ozone and particulates by controlling the emissions of sulphur dioxide, oxides of nitrogen and dust from large combustion plant. To reduce emissions of Sulphur the plant is fitted with Flue Gas Desulphurisation, and also with a Boosted Over Fire Air system to reduce the concentration of oxides of nitrogen in the flue gas.
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Construction of Arnot Coal Power Station started in 1968, this generation unit went on line in 1971 and the station was fully operational by 1975. Between 1992 and 1997 three of its units were mothballed due to Eskom's surplus generating capacity, but they were brought back online in January 1997, November 1997 and December 1998 respectively.
Power generation is by six 350MW units with at total installed capacity of 2,100MW. Turbine Maximum Continuous Rating is 35.60%.
In addition to feeding the South African grid, Arnot, along with Camden Power Station, also feeds the Mozal Aluminium smelter in Mozambique via 400kV transmission lines. Mozal consumes around 950MW.
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Belews Creek Coal Steam Power Station is a 2.24-GW, two-unit coal-fired generating facility located in Belews Lake in Stokes County, North Carolina. It is Duke Energy’s largest coal-burning power plant in the Carolinas and consistently ranks among the most efficient coal facilities in the United States. During 2006, it was the fifth most efficient coal power plant in the United States with a heat rate of 9,023 Btu/kWh (37.8% conversion efficiency). The remaining 62.2% of energy released by the burning coal is in the form of heat. It is dumped into Belews Lake, a man-made lake created by Duke Power for cooling water purposes in the early 1970s. In 2008, it was the most efficient coal power plant in the United States with a heat rate of 9,204 BTU/KWh.
The Belews Creek Coal Steam Power Station consists of two nearly identical units, launched into operation in 1974 and 1975. Each furnace, a Babcock & Wilcox boiler, heats steam to 1,000 °F (538 °C) in both the secondary superheater and reheater sections. The boilers are supercritical units, operating at 3,400 pounds per square inch (230 atm) of pressure. All four generators (two low pressure generators and two high pressure/intermediate pressure generators) are Westinghouse generators. The high and intermediate-pressure steam turbines were originally Westinghouse units, but were replaced during an Alstom steam-path upgrade. The low pressure turbines are original Westinghouse units.
The Belews Creek Coal Steam Power Station employs multiple pollution control systems, including a selective catalytic reducer which removes nitrogen oxides, an electrostatic precipitator which removes fly ash, and low NOx burners in the boiler. The plant has completed a $500 million flue gas desulfurization project which came online during the beginning of 2008. This project has reduced the plant's sulfur dioxide emissions by 95%.
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The Turceni Coal Power Station is Romania's largest electricity producer and one of the largest thermal power plants in Europe having 7 identical groups of 330 MW each thus totalling an installed capacity of 2,310 MW.
It uses coal from Jilţ Coal Mine and Tehomir underground mine.
The coal power plant is situated in the Gorj County (South-Western Romania), on the banks of the Jiu River, half way between the cities of Craiova and Târgu Jiu.
The four chimneys are 280 metres tall.
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Lawsuit over Air Pollution at Martin Lake Plant
In July, 2007, the Sierra Club put EFH and its subsidiary, Luminant, on notice that the group intended to sue the company for Clean Air Act violations at its Martin Lake plant. The plant was rated as the first in the nation for power plant mercury emissions in 2005, emitting a total of 1,705 pounds of mercury that year. The Sierra Club claimed that both the U.S. EPA and the Texas Commission on Environmental Quality ignored soot pollution and other violations at the facility. They also claimed that Martin Lake was one of the dirtiest plants in the entire country in regard to particle pollution, mercury, sulfur dioxide, nitrogen oxide, and carbon dioxide. These toxins, the Sierra Club noted, are producing a great health risk to communities nearby. The facility currently uses scrubber technology.
In September 2010, EFH and its Luminant Generation unit were sued by the Sierra Club over pollution emitted by the Martin Lake plant. The plant near Longview is among the dirtiest in the U.S., the environmental group said in its complaint filed in federal court in Texarkana, Texas: “It is the worst power plant for mercury pollution among all U.S. coal plants, emitting 1,764 pounds in 2008,” the Sierra Club said in a statement. The San Francisco-based group asked a judge to find the plant’s operators in violation of the U.S. Clean Air Act.
Environmental Integrity Project Reports Luminant's Martin Lake Plant Nation's Worst for Mercury Emissions
In March 2010 the Environmental Integrity Project (EIP) released a report using available EPA data that indicated half of the country's 50 largest mercury-emitting power plants have increased their emissions in recent years. The report also noted that half of the coal plants in the United States do not have the most up to date emission controls in place, and five of the plants with the highest amount of mercury emitted are located in Texas.
Coal-fired power plants generate more than 40 percent of U.S. emissions. Mercury released into the air settles in rivers and lakes, where it moves through the food chain to the fish that people eat. The report states that Luminant's Martin Lake Steam Station in Texas is the nation's worst mercury polluter. The plant reported a 4.56 percent increase from 2007 to 2008.
Martin Lake ranked 5th in largest carbon dioxide emissions
Martin Lake Coal Power Plant ranked 5th in terms of largest carbon dioxide emissions according to a 2009 report by Environment America, "America's Biggest Polluters," the Martin Lake station is the fifth dirtiest plant in the nation, releasing 21.8 million tons of carbon dioxide in 2007. Ranking is based upon Environmental Protection Agency data.
- Owner: Energy Future Holdings
- Parent Company: Luminant
- Plant Nameplate Capacity: 2,380 MW
- Units and In-Service Dates: 793 MW (1977), 793 MW (1978), 793 MW (1979)
- Location: 8850 FM 2658 N., Tatum, TX 75691
- GPS Coordinates: 32.259167, -94.568611
- Coal Consumption:
- Coal Source:
- Number of Employees:
- 2006 CO2 Emissions: 21,301,393 tons
- 2006 SO2 Emissions: 77,419 tons
- 2006 SO2 Emissions per MWh:
- 2006 NOx Emissions: 15,608 tons
- 2005 Mercury Emissions: 1,705 lb.
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Longannet coal power station is a large coal-fired power station in Fife capable of co-firing biomass, natural gas and sludge. The station is situated on the north bank of the Firth of Forth, near Kincardine on Forth. Its generating capacity of 2,400 megawatts is the highest of any power station in Scotland. The station began generating electricity in 1970, and when in became fully operational, it was the largest coal-fired station in Europe. It is now the third largest, after Bełchatów in Poland and Drax in England.
The Longannet coal power station was opened in 1973 and operated by the South of Scotland Electricity Board, until 1991 when its operation was handed over to Scottish Power following privatisation. The station is a regional landmark, dominating the Forth skyline with its 183 m (600 ft) chimney stack. Like most power stations in Scotland Longannet lacks cooling towers. Instead it uses water from the River Forth for cooling.
The Longannet coal power station consumes up to 4,500,000 tonnes of coal each year. Coal is delivered either by road or rail to the station's coal store, which has the capacity to hold up to 2,000,000 tonnes. Coal is fed from the coal store to the power station by a conveyor belt which is capable of carrying 3,500 tonnes of coal per hour. Coal is fed into bunkers inside the station's boiler house. These feed the station's pulverisers which supply the boilers' burners with fuel. Each of the pulverisers are capable of pulverising 40 tonnes of coal an hour. There are eight pulverisers per each of the station's four Foster Wheeler boilers. These use low NOx burners made by ABB Combustion Ltd. Each boiler provides steam for two 300 megawatt General Electric Company turbo generators.
Coal was originally supplied directly by conveyor belt from the neighbouring Longannet Colliery. This was the last deep mine in Scotland. It closed in 2002. The station is still supplied by Scotland's open cast mines. Much of the station's coal must now be imported, the majority via the former British Steel ore loading facility at Hunterston Terminal in Ayrshire. Onward transport is by rail and the level of traffic required to supply Longannet's fuel demand has caused extreme congestion on the Scottish rail network. An alternative route, the Stirling-Alloa-Kincardine rail link, at the mouth of the river Forth was reopened in 2008.
Water is taken for the station's cooling condensers from the Firth of Forth at a rate of 327,000m3 per hour. The water is passed through coarse screens and then circulated by four electrically driven pumps. Once circulated through the station's condensers (which cool the turbines' exhaust heat), the water is discharged into a mile long cooling channel, where heat is dissipated with no harmful effect before reaching a wide part of the Forth.
Electrostatic precipitators and sulphur trioxide conditioning
The Longannet coal power station is fitted with electrostatic precipitators (ESP) to reduce the stations particulate emissions. In the late 1980s the station's units were fitted with sulphur trioxide (SO3) conditioning equipment to lower the fly ash's electrical resistivity. This was to ensure the station maintained allowable particulate emissions. Between 1989 and 1994 the station's ESPs were given a major refurbishment. This meant that the SO3 conditioning equipment didn't need to be operated as frequently to maintain the allowed level of particulate emissions. This is beneficial as SO3 is seen as a hazardous substance.
In 1994, the Longannet coal power station was awarded funding from the European Commission under the THERMIE Demonstration Programme. With this money, Unit 2 at the station was retrofitted with Gas-reburn Technology. This is the largest scale application of this technology in the world. In this process, natural gas is injected into the boiler. This cuts NOx emissions from Unit 2 by 50%, as well as giving a reduction in CO2 and SO2 emissions. Also in 1996, all of the station's boilers were fitted with Low NOx burners. This reduced the station's NOx emissions by 40%.
In 2003, Longannet coal power station was named as Scotland's biggest polluter in a report by the Scottish Environment Protection Agency (SEPA). The station produces up to 4,350 tonnes of ash per day. This is piped to ash lagoons on the nearby Preston Island, where it is stored in former salt pans. This is then landscaped and used to reclaim the land from the Firth of Forth.
To improve environmental emissions, Longannet is now fitted with 'Low-NOx' burners to limit the formation of oxides of nitrogen and a 'Gas Reburn system' that uses natural gas to convert NOx into nitrogen and water vapour. Longannet also burns up to 65,000 tonnes of treated and dried sewage sludge per year, which has a similar calorific value to low-quality brown coal. In 2005, a judge ruled the burning of sludge as illegal, but the SEPA continues to allow Scottish Power to burn the sludge illegally as part of an agreement which requires Scottish Power to construct, and have in operation, a biomass plant in 2010.
In 2007 the WWF named Europe's 30 most climate polluting power stations in absolute terms; of these, Longannet was the most polluting in the UK (relative to power output).
The UK's first ever carbon capture and storage (CCS) unit was commissioned at the station in 2009.
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Navajo Coal Generating Station is a coal-fired powerplant with a power of 2280 megawatts located on the Navajo Indian Reservation, near Page, Arizona, USA. Navajo Generating Station has three 236 meter high chimneys, which are among the tallest structures in Arizona. This plant provides electrical power to customers in Arizona, Nevada, and California. It was assembled during the 1970s and began producing commercial power in 1975. The construction costs were about $650 million, with an additional $420 million for new environmental scrubbers, constructed during the 1990s.
The Navajo Coal Power Plant is served by coal mined at the Kayenta Mine near Kayenta, Arizona, and hauled by the Black Mesa and Lake Powell railroad. The Kayenta mine ships about 8 million tons of coal each year to the power plant.The Navajo Coal Power Plant emits 19.9 million tons of CO2 per year. The power plant is equipped with electrostatic precipitators to control fly ash, and has a lined water reservoir to help recover and contain process waste. The power plant features scrubbers for each tower to control SO2 pollution. The project began in 1994 and was completed in 1999.
|Navajo Generating Station|
|Locale||Navajo Nation, near Page, Arizona, USA|
|Power station information|
|Power generation information|
|Installed capacity||2250 MW|
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Pulverized coal power plants first appeared in the 1920s and serve as the backbone of the power sector in the U.S. Pulverized coal remains a relatively simple technology, converting a little more than one-third of the fuel’s energy potential into useful electricity.
Pulverized coal power generation starts by crushing coal into a fine powder that is fed into a boiler where it is burned to create heat. The heat produces steam that is used to spin one or more turbines to generate electricity. Subcritical plants make up the bulk of the U.S. pulverized coal system, with efficiencies for new plants usually around 37 percent. Supercritical plants use higher pressure and temperatures to boost efficiency to 40 percent or more. Ultra-supercritical, using still higher pressures, achieves 42-45 percent efficiency.
Pulverized coal power plants have gained renewed interest this decade due to surging natural gas prices. The levelized cost of electricity generated at most pulverized coal plants in the U.S. is currently less than that of natural gas combined-cycle plants. While the capital costs of gas-fired combined-cycle units are only half that of pulverized coal, the fuel costs are much higher and often unstable. Utilities pay special attention to predictability of prices and currently shy away from high and unstable natural gas prices. Moreover, as domestic production of natural gas is limited, further additions to gas-fired power generation would require more imported liquefied natural gas, and exacerbate energy security concerns.
Coal dust suspended in air is explosive -- coal dust has far more surface area per unit weight than chunks of coal, and is more susceptible to spontaneous combustion. As a result, a nearly empty coal store is a greater explosion risk than a full one. The worst mining accidents in history have been caused by coal dust explosions, such as the disaster at Senghenydd in South Wales in 1913 in which 439 miners died, the Courrières mine disaster in Northern France which killed 1099 miners, the Luisenthal Mine disaster in Germany, which claimed 299 lives in 1962, and the worst: the explosion at Benxihu Colliery, China, which killed 1549 in 1942. Such accidents were usually initiated by firedamp ignitions, the shock wave of which raised dust from the floor of the mine galleries to make an explosive mixture. The problem was investigated by Michael Faraday and Charles Lyell in the explosion at the colliery at Haswell County Durham of 1844, but their conclusions were ignored at the time.
The main attempts at prevention include using safety lamps, adding stone dust coffers to mine galleries, watering workings and ensuring efficient ventilation of all the workings.
Lung and skin problems
Coal workers' pneumoconiosis, or black lung disease, is caused by inhaling coal dust, typically dust produced in coal mining.
According to George Orwell, coal miners could develop characteristic tattoos owing to coal dust getting into wounds. This can also occur with substances like gunpowder.
Pulverized coal-fired boilerA pulverized coal-fired boiler is an industrial or utility boiler that generates thermal energy by burning pulverized coal (also known as powdered coal or coal dust). This type of boiler dominates the electric power industry, providing steam to drive large turbines. Pulverized coal provides the thermal energy which produces about 50% of the world's electric supply.
The Milwaukee Electric Railway and Light Company, later Wisconsin Electric, conducted tests in the use of pulverized coal at its Oneida Street power plant in 1918. These experiments helped Fred L. Dornbrook to develop methods of controlling the pulverized coal's tarry ash residues with boiler fed water tube jackets that served to reduce the surface temperature of the firebox walls and allowed the ash deposits be easily removed. This plant became the first central power station in the United States to use pulverized fuel.
The Oneida Street power plant near Milwaukee's City Hall was subsequently decommissioned and renovated in 1987. It is now the site of the Milwaukee Repertory Theatre.
Pulverized coal power plants are broken down into three categories; subcritical pulverized coal (SubCPC) plants, supercritical pulverized coal (SCPC) plants, and ultra-supercritical pulverized coal (USCPC) plants. The primary difference between the three types of pulverized coal boilers are the operating temperatures and pressures with subcritical plants operating at the lowest temp and pressure ranges, ultra-supercritical plants are at the highest ranges, and supercritical plants in the middle. As the pressures and temperatures increase, so does the operating efficiency. Subcritical plants are at about 37%, supercriticals at about 40% and ultra-supercriticals in the 42-45% range.
Pulverised fuel firingPulverised fuel firing is a solid fuel burning technique in which the fuel is pulverised before being ignited. It is the most common method of burning coal and oil shale for power generation. The basic idea of a firing system using pulverised fuel is to use the whole volume of the furnace for the combustion of solid fuels. Coal is ground to the size of a fine grain, mixed with air and burned in the flue gas flow. Biomass and other materials can also be added to the mixture. Coal contains mineral matter which is converted to ash during combustion. The ash is removed as bottom ash and fly ash. The bottom ash is removed at the furnace bottom There are two methods of ash removal at furnace bottom:
- Dry bottom boiler
- Wet bottom boiler, also called Slag tap
The fly ash is carried away with the flue gas and is separated in various hoppers in the path and finally in an ESP or a bag filter.
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The first power station in Frimmersdorf, fired with lignite, was established in 1926 and had an output of 26 megawatts. In 1954 this was replaced with a much larger plant that contained two 100 MW units. Over the next 15 years, this was incrementally upgraded until it supported an additional twelve 150 MW units and two 300 MW units. 1988 saw the installation of a flue gas desulphurating plant, while the two 100 MW units were shut down on 30 June.
Frimmersdorf Coal Power Station is the dirtiest power station in Europe and the third most polluting power station in the industrialised world (based on CO2 per megawatt hour sent out).