Longannet power station
Encyclopedia
Longannet power station lɒŋˈænɨt 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 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 (600.4 ft) chimney stack. Like most power stations in Scotland, Longannet lacks cooling tower
s. Instead it uses water from the River Forth for cooling.
. Construction began in the mid-1960s, 4 km (2.5 mi) downstream of the existing Kincardine power station
. The station was constructed on land reclaimed from the Firth of Forth using ash from the Kincardine station. Longannet was in full operation by 1973. At the time of its completion, the station was the largest in Europe.
nuclear stations. There are four 600 MWe generation units, each featuring a single boiler
feeding two 300 MWe GEC turbo-alternators, with the steam spaces cross coupled. The declared net capacity is rated at 2,304 MW due to operational losses. On average Longannet produces 10.4 TW·h (terawatt hours) per year and in 2000-2001 achieved the highest generation output in its history by supplying more than 12.25 TW·h to the National Grid.
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 generator
s.
. 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.
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.
s (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.
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%.
(SEPA). The station produces up to 4,350 tonne
s of ash per day. This is piped to ash lagoons on the nearby Preston Island, where it is stored in former salt pan
s. 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.
, as a subsidiary of the Spanish
Electricity Company, Iberdrola
.
s.
Fossil fuel power plant
A fossil-fuel power station is a power station that burns fossil fuels such as coal, natural gas or petroleum to produce electricity. Central station fossil-fuel power plants are designed on a large scale for continuous operation...
in Fife
Fife
Fife is a council area and former county of Scotland. It is situated between the Firth of Tay and the Firth of Forth, with inland boundaries to Perth and Kinross and Clackmannanshire...
capable of co-firing biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
, natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
and sludge
Sludge
Sludge refers to the residual, semi-solid material left from industrial wastewater, or sewage treatment processes. It can also refer to the settled suspension obtained from conventional drinking water treatment, and numerous other industrial processes...
. The station is situated on the north bank of the Firth of Forth
Firth of Forth
The Firth of Forth is the estuary or firth of Scotland's River Forth, where it flows into the North Sea, between Fife to the north, and West Lothian, the City of Edinburgh and East Lothian to the south...
, 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
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
. It is now the third largest, after Bełchatów in Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
and Drax in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
.
The station was opened in 1973 and operated by the South of Scotland Electricity Board
South of Scotland Electricity Board
The South of Scotland Electricity Board , was formed as a result of the Electricity Reorganisation Act 1954. On 1 April 1955, the two southern Scottish Area Electricity Boards were merged into the South of Scotland Electricity Board...
, until 1991 when its operation was handed over to Scottish Power
Scottish Power
ScottishPower Ltd. is a vertically integrated energy company with its headquarters in Glasgow, Scotland. It was listed on the London Stock Exchange and was once a constituent of the FTSE 100 Index but in 2006 it became a subsidiary of the Spanish utility Iberdrola...
following privatisation. The station is a regional landmark, dominating the Forth skyline with its 183 m (600.4 ft) chimney stack. Like most power stations in Scotland, Longannet lacks cooling tower
Cooling tower
Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or in the case of closed circuit dry cooling towers rely...
s. Instead it uses water from the River Forth for cooling.
History
The station was designed by Scottish architects Robert Matthew, Johnson Marshall & PartnersRMJM
RMJM is an international architectural practice founded in Edinburgh, Scotland in 1956 by architects Robert Matthew and Stirrat Johnson-Marshall. The first offices of the practice were its headquarters in Edinburgh, and another in London...
. Construction began in the mid-1960s, 4 km (2.5 mi) downstream of the existing Kincardine power station
Kincardine power station
Kincardine power station was a large coal-fired power station on the shores of the upper Firth of Forth by Kincardine on Forth, Fife, Scotland....
. The station was constructed on land reclaimed from the Firth of Forth using ash from the Kincardine station. Longannet was in full operation by 1973. At the time of its completion, the station was the largest in Europe.
Design and specification
Longannet has an installed capacity of 2,400 MWe (megawatts electrical) which is equivalent to two Advanced gas-cooled reactorAdvanced gas-cooled reactor
An advanced gas-cooled reactor is a type of nuclear reactor. These are the second generation of British gas-cooled reactors, using graphite as the neutron moderator and carbon dioxide as coolant...
nuclear stations. There are four 600 MWe generation units, each featuring a single boiler
Boiler
A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications.-Materials:...
feeding two 300 MWe GEC turbo-alternators, with the steam spaces cross coupled. The declared net capacity is rated at 2,304 MW due to operational losses. On average Longannet produces 10.4 TW·h (terawatt hours) per year and in 2000-2001 achieved the highest generation output in its history by supplying more than 12.25 TW·h to the National Grid.
Electricity generation
The station consumes up to 4,500,000 tonnes of coalCoal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
each year. Coal is delivered either by road or rail
Rail transport
Rail transport is a means of conveyance of passengers and goods by way of wheeled vehicles running on rail tracks. In contrast to road transport, where vehicles merely run on a prepared surface, rail vehicles are also directionally guided by the tracks they run on...
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
Conveyor belt
A conveyor belt consists of two or more pulleys, with a continuous loop of material - the conveyor belt - that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley...
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
NOx
NOx is a generic term for the mono-nitrogen oxides NO and NO2 . They are produced from the reaction of nitrogen and oxygen gases in the air during combustion, especially at high temperatures...
burners made by ABB Combustion Ltd. Each boiler provides steam for two 300 megawatt General Electric Company turbo generator
Turbo generator
A turbo generator is a turbine directly connected to an electric generator for the generation of electric power. Large steam powered turbo generators provide the majority of the world's electricity and are also used by steam powered turbo-electric ships.Smaller turbo-generators with gas turbines...
s.
Coal supply
Coal was originally supplied directly by conveyor belt from the neighbouring Longannet CollieryLongannet coal mine
-History:Longannet was the remnant of three mines, established in the 1960s. Built on the north side of the Firth of Forth, east of Kincardine, it connected with the Bogside, Castlehill and Solsgirth Collieries, forming a single, five miles long, tunnel...
. 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
British Steel
British Steel was a major British steel producer. It originated as a nationalised industry, the British Steel Corporation , formed in 1967. This was converted to a public limited company, British Steel PLC, and privatised in 1988. It was once a constituent of the FTSE 100 Index...
ore loading facility at Hunterston Terminal
Hunterston Terminal
Hunterston Terminal, in North Ayrshire, Scotland, is a coal-handling port located at Fairlie on the Firth of Clyde, and operated by Clydeport. It lies adjacent to Hunterston estate, site of Hunterston Castle....
in Ayrshire
Ayrshire
Ayrshire is a registration county, and former administrative county in south-west Scotland, United Kingdom, located on the shores of the Firth of Clyde. Its principal towns include Ayr, Kilmarnock and Irvine. The town of Troon on the coast has hosted the British Open Golf Championship twice in the...
. 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
Stirling-Alloa-Kincardine rail link
The Stirling-Alloa-Kincardine rail link was a project to re-open of railway line between the towns of Stirling, Alloa and Kincardine in Scotland, United Kingdom. The route opened to rail traffic in March 2008.- Background :...
, at the mouth of the river Forth was reopened in 2008.
Cooling system
Water is taken for the station's cooling condensers from the Firth of ForthFirth of Forth
The Firth of Forth is the estuary or firth of Scotland's River Forth, where it flows into the North Sea, between Fife to the north, and West Lothian, the City of Edinburgh and East Lothian to the south...
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 station is fitted with electrostatic precipitatorElectrostatic precipitator
An electrostatic precipitator , or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas using the force of an induced electrostatic charge...
s (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.
NOx reduction
In 1994, the station was awarded funding from the European CommissionEuropean Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
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
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
is injected into the boiler. This cuts NOx
NOx
NOx is a generic term for the mono-nitrogen oxides NO and NO2 . They are produced from the reaction of nitrogen and oxygen gases in the air during combustion, especially at high temperatures...
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%.
Environmental impact
In 2003, Longannet was named as Scotland's biggest polluter in a report by the Scottish Environment Protection AgencyScottish Environment Protection Agency
The Scottish Environment Protection Agency is Scotland’s environmental regulator. Its main role is to protect and improve Scotland's environment...
(SEPA). The station produces up to 4,350 tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s of ash per day. This is piped to ash lagoons on the nearby Preston Island, where it is stored in former salt pan
Dry lake
Dry lakes are ephemeral lakebeds, or a remnant of an endorheic lake. Such flats consist of fine-grained sediments infused with alkali salts. Dry lakes are also referred to as alkali flats, sabkhas, playas or mud flats...
s. 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
NOx
NOx is a generic term for the mono-nitrogen oxides NO and NO2 . They are produced from the reaction of nitrogen and oxygen gases in the air during combustion, especially at high temperatures...
and a 'Gas Reburn system' that uses natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
to convert NOx into nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
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
Scottish Power
ScottishPower Ltd. is a vertically integrated energy company with its headquarters in Glasgow, Scotland. It was listed on the London Stock Exchange and was once a constituent of the FTSE 100 Index but in 2006 it became a subsidiary of the Spanish utility Iberdrola...
to burn the sludge illegally as part of an agreement which requires Scottish Power to construct, and have in operation, a biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
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
Carbon capture and storage
Carbon capture and storage , alternatively referred to as carbon capture and sequestration, is a technology to prevent large quantities of from being released into the atmosphere from the use of fossil fuel in power generation and other industries. It is often regarded as a means of mitigating...
(CCS) unit was commissioned at the station in 2009.
Ownership
This facility is owned and operated by Scottish PowerScottish Power
ScottishPower Ltd. is a vertically integrated energy company with its headquarters in Glasgow, Scotland. It was listed on the London Stock Exchange and was once a constituent of the FTSE 100 Index but in 2006 it became a subsidiary of the Spanish utility Iberdrola...
, as a subsidiary of the Spanish
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
Electricity Company, Iberdrola
Iberdrola
Iberdrola , headquartered in Bilbao, is a private utility with a global footprint and over 150 years of experience...
.
Future
The station is expected to continue operating until approximately 2020-2025, because of the technical advancements in place at the station. These include the station's low NOx burners, its NOx reburn system and a refurbishment of the station's electrostatic precipitatorElectrostatic precipitator
An electrostatic precipitator , or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas using the force of an induced electrostatic charge...
s.