Longannet Power Station closes
By John Le Marie
Longannet Power Station formally closed on Thursday (31st March) after ceasing to output to the grid on Thursday 24th March. It is the last of the coal-fired power stations to close in Scotland.
It first began generating electricity in 1970 and once fully commissioned, was the largest coal-fired station in Europe. Prior to its closure it was the third largest, after Belchat? in Poland and Drax in England. However with its installed generating capacity of 2,400 megawatts it remained the highest of any power station in Scotland.
The design lifespan of Longannet was 30 years, but owing to various modifications over the years its operation was extended. More recently the plant had tested additional technologies which would have allowed it to continue operating to beyond 2020 under EU emissions regulations.
When first built the plant was operated by South of Scotland Electricity Board (SSEB). In 1990 operation was handed over to Scottish Power under privatisation, who later were bought by Iberdrola, a Spanish company, in 2006. It has continued to trade under the name Scottish Power, whilst a subsidiary of the Spanish utility.
Longannet was designed to be a coal-fired station, with initially much of the coal being delivered directly by conveyor belt from the neighbouring Longannet Colliery. However the latter was closed in 2002, following a flood. Since the loss of the colliery, supplies have been partly Scottish and the remainder imported.
In the late 1980s the station’s units were fitted with electrostatic precipitators (ESPs) and sulphur trioxide (SO3) conditioning. Between 1989 and 1994 the ESPs were given a major refurbishment. These actions were to ensure the station maintained allowable particulate levels.
Over the period 1994 to 1996 the station was fitted was Gas-Reburn Technology, which involved injecting natural gas into the boilers. This cut the generation of nitrous oxides (NOx) emissions by 40% as well as a reduction in the emissions of carbon dioxide (CO2) and sulphur dioxide (SO2).
In 2009 the UK’s first ever carbon capture and storage (CCS) unit was commissioned at the station. It closed in 2011 after it became clear that it was not financially viable. Elsewhere around the world, attempts at CCS have proved not to be cost effective.
Besides burning coal, typically 4,500,000 tonnes per year, Longannet in more recent years burnt 65,000 tonnes of treated and dried sewerage along with waste-derived fuel and sawdust pellets. The burning of the alternative fuels was permitted by SEPA on the understanding that Scottish Power would have a biomass plant in operation by 2010. This did not happen and all burning of biomass and waste-derived fuel ceased in 2012.
The thermal efficiency of Longannet was 37%. To put this into context, the very latest turbine technology is capable of producing a 55% efficiency. This is of no consequence in a world where coal is fast becoming a fuel of the past.
Efficiency is not the only issue. In 2003 Longannet was named as Scotland’s biggest polluter by the Scottish Environment Protection agency (SEPA). In 2007, WWF named Europe’s 30 most climate polluting power stations, with Longannet being the most polluting in the UK (relative to power output). It was the 21st most polluting power station in Europe.
It is not clear yet what will happen to the Longannet buildings and iconic 183m (600 ft) chimney stack, along with the large area of adjacent coastal land owned by Scottish Power. There are also the associated ash lagoons, these having merged with Preston Island, an industrial relic of earlier times. The retention of the chimney as a regional landmark and as a reminder of when coal was king is something the power company might want to consider.
Our photos (top) show Longannet working hard to keep the lights on – Christmas Day 2005 - and Longannet looking lifeless and forlorn on 31 March 2016. (Photos: John Le Marie)
Blairhall Bogside Cairneyhill Carnock Comrie Crombie Culross Gowkhall Kilbagie Kincardine Newmills Oakley Saline Steelend Torryburn Valleyfield