Longannet power station was a large
coal-fired power station in
Fife, and the last coal-fired power station in Scotland. It was capable of
co-firing {{No footnotes, date=November 2010
Co-firing is the combustion of two (or more) different types of materials at the same time. One of the advantages of co-firing is that an existing plant can be used to burn a new fuel, which may be cheaper or more ...
biomass,
natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
and
sludge
Sludge is a semi-solid slurry that can be produced from a range of industrial processes, from water treatment, wastewater treatment or on-site sanitation systems. For example, it can be produced as a settled suspension obtained from conventional ...
. The station stood on the north bank of the
Firth of Forth, near
Kincardine on Forth
Kincardine ( ; gd, Cinn Chàrdainn) or Kincardine-on-Forth is a small town on the north shore of the Firth of Forth, in Fife, Scotland. The town was given the status of a burgh of barony in 1663. It was at one time a reasonably prosperous mi ...
.
Its generating capacity of 2,400
megawatt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James ...
s was the highest of any power station in Scotland. The station began generating electricity in 1970,
and when it became fully operational it was the largest coal-fired station in Europe. At the time of closure it was the third largest, after
Bełchatów
Bełchatów () is a city in central Poland with a population of 55,583 as of December 2021. It is located in Łódź Voivodeship, from Warsaw.
The Elektrownia Bełchatów, located in Bełchatów, is the largest coal fueled power plant in ...
in Poland and
Drax in England, and the 21st most polluting.
Longannet was operated by the
South of Scotland Electricity Board
The South of Scotland Electricity Board (SSEB) generated, transmitted and distributed electricity throughout the south of Scotland, including the former regions of Strathclyde, Lothian, Fife, Central, Borders and Dumfries and Galloway and a few t ...
until 1990, when its operation was handed over to
Scottish Power
Scottish Power is a vertically integrated energy company based in Glasgow, Scotland. It is a subsidiary of Spanish utility firm Iberdrola.
ScottishPower is the distribution network operator for Central and Southern Scotland, Merseyside, Nor ...
following privatisation. After failing to win a contract from
National Grid, the station closed on 24 March 2016.
The station was a regional landmark, dominating the Forth skyline with its chimney stack. Longannet lacked
cooling tower
A cooling tower is a device that rejects waste heat to the atmosphere through the cooling of a coolant stream, usually a water stream to a lower temperature. Cooling towers may either use the evaporation of water to remove process heat an ...
s, having instead used water from the
River Forth
The River Forth is a major river in central Scotland, long, which drains into the North Sea on the east coast of the country. Its drainage basin covers much of Stirlingshire in Scotland's Central Belt. The Gaelic name for the upper reach of t ...
for cooling. On 4 February 2021, the boiler house, turbine hall and control room were demolished in a controlled explosion.
On 9 December 2021, the chimney stack was demolished.
History
The station was designed by Scottish architects
Robert Matthew, Johnson Marshall & Partners. Consulting Engineers were
Merz and McLellan. Construction began in 1964,
downstream of the existing
Kincardine power station
Kincardine power station was a 760 MW coal-fired power station on the shores of the upper Firth of Forth by Kincardine on Forth, Fife, Scotland.
History
The station began construction in 1952 and started generating electricity in 1958. At the ...
. The station was constructed on of land reclaimed from the Firth of Forth using ash from the Kincardine station. It began generating electricity in 1970, with a
design lifetime of 30 years, and was in full operation by 1973.
At the time of its completion, the station was the largest in Europe.
The facility was operated by the
South of Scotland Electricity Board
The South of Scotland Electricity Board (SSEB) generated, transmitted and distributed electricity throughout the south of Scotland, including the former regions of Strathclyde, Lothian, Fife, Central, Borders and Dumfries and Galloway and a few t ...
until 1990 when the
electricity industry in the UK was privatised.
After that it was operated by
Scottish Power
Scottish Power is a vertically integrated energy company based in Glasgow, Scotland. It is a subsidiary of Spanish utility firm Iberdrola.
ScottishPower is the distribution network operator for Central and Southern Scotland, Merseyside, Nor ...
, a subsidiary of
Iberdrola
Iberdrola () is a Spanish multinational electric utility company based in Bilbao, Spain. Iberdrola has a workforce of around 34,000 employees serving around 31.67 million customers. Subsidiaries include Scottish Power (United Kingdom) ...
.
It paid £40m per year in connection charges to National Grid due to its distance from South England.
The plant opted in to the UK Transitional National Plan, placing limits on its sulphur dioxide, nitrous oxides and particulates emissions. The plant tested additional technologies that could have permitted it to operate beyond 2020 under the EU
Industrial Emissions Directive
The Industrial Emissions Directive (Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial emissions (integrated pollution prevention and control)) is a European Union directive which commits Europea ...
.
The station closed on 24 March 2016.
[
]
Demolition
Demolition at the site commenced in November 2018 with the 'blow down' of the coal stock towers. The eastern boiler annexe was demolished on 11 April 2019. The boiler house, turbine hall and control room were all demolished on 4 February 2021.
On 9 December 2021, the chimney stack was demolished. Three days before this, Scottish Power had illuminated a slogan onto the chimney that read "Make Coal History". The explosives were triggered by the First Minister of Scotland, Nicola Sturgeon.
Design and specification
Longannet had an installed capacity of 2,400 MW and a declared net capacity of 2,304 MW due to plant overheads. The station produced 9,525 GWh of electricity in 2012, an increase on the 9,139 GWh produced in 2011.
Electricity generation
The station consumed up to of coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal is formed when ...
each year. Coal was delivered either by road or rail
Rail or rails may refer to:
Rail transport
*Rail transport and related matters
*Rail (rail transport) or railway lines, the running surface of a railway
Arts and media Film
* ''Rails'' (film), a 1929 Italian film by Mario Camerini
* ''Rail'' ( ...
to the station's coal store, which had the capacity to hold up to 2,000,000 tonnes. It was then fed from the coal store to the boiler house by a conveyor belt capable of carrying 3,500 tonnes of coal per hour.
Each of the four boilers was serviced by eight pulverising units, each capable of processing 40 tonnes of coal an hour.[ The front-wall-fired Foster Wheeler boilers could each burn around 250 tonnes of coal an hour at full load.][ There were two forced ]draft
Draft, The Draft, or Draught may refer to:
Watercraft dimensions
* Draft (hull), the distance from waterline to keel of a vessel
* Draft (sail), degree of curvature in a sail
* Air draft, distance from waterline to the highest point on a vesse ...
and two induced draft fans on each boiler. Each boiler provided around 1,800 tonnes per hour of steam at a pressure of and a temperature of to two 300 MW General Electric Company turbo generator
A turbo generator is an electric generator connected to the shaft of a steam turbine or gas turbine for the generation of electric power. Large steam-powered turbo generators provide the majority of the world's electricity and are also use ...
s. The thermal efficiency
In thermodynamics, the thermal efficiency (\eta_) is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, steam turbine, steam engine, boiler, furnace, refrigerator, ACs etc.
For a ...
of the plant was around 37%.[
]
Coal supply
Coal was originally supplied directly by conveyor belt from the neighbouring Longannet Colliery, until it closed in 2002 after a flood.[ Around half of the coal used was Scottish, and the rest had to be imported, the majority via the former ]British Steel plc
British may refer to:
Peoples, culture, and language
* British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies.
** Britishness, the British identity and common culture
* British Englis ...
ore loading facility at Hunterston Terminal
Hunterston Terminal, in North Ayrshire, Scotland, was an iron ore and coal-handling port located at Fairlie on the Firth of Clyde, operated by Clydeport which was taken over by The Peel Group in 2003. It lies south of Fairlie, adjacent to Hunt ...
in Ayrshire.[ Onward transport was by rail and the level of traffic required to supply Longannet's fuel demand caused 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, and was also used to deliver coal.
]
Cooling system
The chimney was tall; the station did not have cooling tower
A cooling tower is a device that rejects waste heat to the atmosphere through the cooling of a coolant stream, usually a water stream to a lower temperature. Cooling towers may either use the evaporation of water to remove process heat an ...
s, instead using water drawn from the Firth of Forth at a rate of per hour for the station's cooling condensers.[ The water was passed through coarse screens and then circulated by four electrically driven pumps.][ Once circulated through the station's condensers, the water was discharged into a mile long cooling channel, where heat was dissipated before the water reached a wide part of the Forth.] Water used by the boilers was on a different cycle, and had to be deionised. Losses from this supply were made up by a plant capable of treating of water per hour.[
]
Electrostatic precipitators and sulphur trioxide conditioning
The station was fitted with electrostatic precipitator
An electrostatic precipitator (ESP) is a filterless device that removes fine particles, like dust and smoke, from a flowing gas using the force of an induced electrostatic charge minimally impeding the flow of gases through the unit.
In con ...
s (ESP) to reduce the station's 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 did not need to be operated as frequently to maintain the allowed level of particulate emissions. This was beneficial as SO3 is hazardous.
NOx reduction
In 1994, the station was awarded funding from the European Commission
The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body ...
under the THERMIE Demonstration Programme. With this money, Unit 2 at the station was retrofitted with gas-reburn equipment. This was the largest scale application of this technology in the world. In this process, natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
is injected into the boiler. This cut NOx
In atmospheric chemistry, is shorthand for nitric oxide () and nitrogen dioxide (), the nitrogen oxides that are most relevant for air pollution.
These gases contribute to the formation of smog and acid rain, as well as affecting tropo ...
emissions from Unit 2 by 50%, as well as giving a reduction in CO2 and SO2 emissions. In 1996, all the station's boilers were fitted with Low NOx burners. This reduced the station's NOx emissions by 40%.
The blend of coal fed to each unit was intended to minimise emissions of sulphur.[
]
Carbon capture and storage
The UK's first carbon capture and storage
Carbon capture and storage (CCS) or carbon capture and sequestration is the process of capturing carbon dioxide (CO2) before it enters the atmosphere, transporting it, and storing it (carbon sequestration) for centuries or millennia. Usually th ...
(CCS) unit was commissioned at the station in 2009. It closed in 2011 after it became clear that it was not financially viable. Plans for a UK Government funded project to convert Longannet to CCS were abandoned in 2011 and no further plans for CCS at Longannet were announced.
Environmental and health impact
In 2003, Longannet was named as Scotland's biggest polluter in a report by the Scottish Environment Protection Agency
The Scottish Environment Protection Agency (SEPA; gd, Buidheann Dìon Àrainneachd na h-Alba) is Scotland's environmental regulator and national flood forecasting, flood warning and strategic flood risk management authority.[tonne
The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...]
s of ash per day. This was piped to ash lagoons surrounding the nearby Preston Island. This was then landscaped and used to claim land from the Firth of Forth.
To improve environmental emissions, Longannet was fitted with 'Low-NOx' burners to limit the formation of oxides of nitrogen Nitrogen oxide may refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds:
Charge-neutral
*Nitric oxide (NO), nitrogen(II) oxide, or nitrogen monoxide
*Nitrogen dioxide (), nitrogen(IV) oxide
* Nitrogen trioxide (), or n ...
and a 'gas reburn system' that used natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
to convert NOx into nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
and water vapour
(99.9839 °C)
, -
, Boiling point
,
, -
, specific gas constant
, 461.5 J/( kg·K)
, -
, Heat of vaporization
, 2.27 MJ/kg
, -
, Heat capacity
, 1.864 kJ/(kg·K)
Water vapor, water vapour or aqueous vapor is the gaseous pha ...
. Longannet used to burn up to 65,000 tonnes of treated and dried sewage sludge
Sewage sludge is the residual, semi-solid material that is produced as a by-product during sewage treatment of industrial or municipal wastewater. The term " septage" also refers to sludge from simple wastewater treatment but is connected to s ...
per year, which has a similar calorific value to low-quality brown coal
Lignite, often referred to as brown coal, is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35%, and is considered the lowest rank of coal due to its relatively low heat ...
. In 2005, a judge ruled the burning of sludge as illegal, but the SEPA continued to allow Scottish Power
Scottish Power is a vertically integrated energy company based in Glasgow, Scotland. It is a subsidiary of Spanish utility firm Iberdrola.
ScottishPower is the distribution network operator for Central and Southern Scotland, Merseyside, Nor ...
to burn the sludge illegally as part of an agreement which originally required Scottish Power to construct, and have in operation, a biomass plant in 2010. All burning of biomass at Longannet – including waste-derived fuel and sawdust pellets – ceased in April 2012.
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). It was the 21st most polluting power station in Europe.
According to a Greenpeace-commissioned report by Stuttgart University
The University of Stuttgart (german: Universität Stuttgart) is a leading research university located in Stuttgart, Germany. It was founded in 1829 and is organized into 10 faculties. It is one of the oldest technical universities in Germany with ...
on the health impacts of the biggest coal-burning power plants in Europe, Longannet was responsible for 4,210 lost 'life years' in 2010.
References
External links
Inside the once-mighty Longannet Power Station
BBC News
{{DEFAULTSORT:Longannet Power Station
Buildings and structures demolished in 2021
Buildings and structures in Fife
Biofuel power stations in Scotland
Waste power stations in Scotland
Coal-fired power stations in Scotland
Former coal-fired power stations in the United Kingdom
Energy infrastructure completed in 1973
1970 establishments in Scotland
2016 disestablishments in Scotland