At the time of opening in the early 1970s Longannet was the largest power station in Europe with a capacity of 2,400 MW. Designed by Scottish architects Robert Matthew, Johnson Marshall & Partners, construction began in 1965 on land reclaimed from the Firth of Forth using ash from the Kincardine power station. The first electricity was generated in 1970 and the station was running at full capacity by 1973 once construction of all units was complete.

Longannet consumed up to 4.5million tonnes of coal per year. The coal was originally supplied via conveyors directly from the nearby Longannet Colliery until its closure in 2002. After that time coal was delivered via rail or road to the station’s coal store which could hold two million tonnes.

Each of the four front-wall-fired boilers, manufactured by Foster Wheeler John Brown, would burn 250 tonnes of coal per hour at full load. Fuel was fed to the boilers from 8 Pulverised Fuel Mills per boiler, each capable of processing 40 tonnes of coal per hour. Each boiler provided around 1,800 tonnes per hour of steam at a pressure of 168 bars and a temperature of 568°C to the turbo-generator sets. The four English Electric turbine sets were each arranged in two lines with a cross-compound arrangement, driving 8 x 300 MW GEC turbo generators.

Cooling water was drawn from the Firth of Forth a rate of 327,000 cubic metres per hour. Longannet did not have any cooling towers, instead discharging its cooling water into a mile long cooling channel, where heat was dissipated before the water reached a wide part of the Forth.

In 2003 Longannet was identified as Scotland’s largest source of pollution. The power station closed in 2016 after 46 years of producing electricity. The closure marked the end of coal-fired generation in Scotland.

Buildings and Plant Detail

Longannet Image Gallery

Visit the plant detail pages above to view more images from each area of the power plant

Carbon Capture and Storage

The UK’s first ever Carbon Capture and Storage (CCS) unit was commissioned at the station in 2009. CCS is a technology that can capture 90% or more of the carbon dioxide (CO₂) emissions produced from the use of fossil fuels in electricity generation. The captured CO₂ is then transported for permanent storage in depleted oil and gas fields.

The unit was 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.

Cross Compound Turbine Arrangement

Longannet utilised a cross-compound arrangement of turbines. Each unit had two turbine lines and therefore two generators per unit. One line incorporated a high-pressure (HP) turbine and two low-pressure (LP) turbines. The second line incorporated two intermediate-pressure (IP) turbines followed by two low pressure turbines. The steam was fed into the HP turbine first, then reheated and fed into the two IP turbines on the second line. After expansion in the IP turbines, the steam was finally divided equally between the four LP turbines. This arrangement has advantages in that the individual casings of the turbines can be smaller and has improved efficiency overall.

The boiler feed pumps were supplied by G&J Weir. Each unit had two starting/standby feed pumps and one primary feed pump driven by a steam turbine utilising steam bled from the high-pressure line.

Longannet Generating Units

List of power generating units at Longannet Power Station:

Turbine Pictures

Boiler Feed Pump Pictures

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The boiler house at Longannet Power Station contained four boilers manufactured by Foster Wheeler John Brown. They were radiant, single 60″ drum, natural circulation boilers with a suspended construction. They contain 246 miles of tubing.

The pulverised fuel mill employed air-swept table/roller pulverisers manufactured by P. H. I. Engineering ltd, each capable of processing 40 tonnes of coal per hour. Each mill had 8 fuel bunkers with a total capacity of 4,000 tonnes per unit. Each boiler provided around 1800 tonnes per hour of steam at a pressure of 168 bars and a temperature of 568°C to the turbo-generator sets.

Boiler House and Mill Pictures

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The nerve centre of operations was the central control room which had been refurbished since the early days of Longannet, to bring the benefits of modern computerised control to the daily operations of units 1-3. Unit 4 retained its original control panels.

The room was fitted with supervisory desks for each unit with sufficient operating equipment to allow the main generating plant to come on-stream, to shut-down and for normal operation. Units were equipped with computer-based automatic boiler controls, on-line data processing equipment and alarm systems which served to monitor continuously and rectify deviations from target conditions to achieve the most efficient operation of the plant.

The new boiler supervisory desks were equipped with the fully integrated APACS self-contained control system, developed by Moore Products Co. The APACS systems included APACS ProcessSuite process automation software and the APACS controller. An integral part of this operating system was LOMIS.

Longannet Operational Management Improvement System (LOMIS)

The aim of the LOMIS system was to optimise the performance of Longannet Power Station. This system was installed on Units 1 and 3.

Control Room Pictures

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The workshops at Longannet were quite expansive and well equipped with various machines for metalworking. The workshop building was directly connected to the turbine hall for ease of transportation between the workshops and power station.

The admin block contained offices, the laboratory and medical facilities.

Workshop Pictures

Admin Block Pictures

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