Didcot power stations

Didcot Power Stations

Didcot Power Station
Viewed from the south in September 2006
Location of Didcot Power Stations in Oxfordshire
Country England
Location Oxfordshire, South East England
Coordinates 51°37′25″N 1°16′03″W / 51.62363°N 1.26757°W / 51.62363; -1.26757Coordinates: 51°37′25″N 1°16′03″W / 51.62363°N 1.26757°W / 51.62363; -1.26757
Commission date 1968
Operator(s) Central Electricity Generating Board
(1968-1990)
National Power
(1990-2000)
Innogy plc
(2000-2002)
RWE npower
(2002-present)
Thermal power station
Primary fuel Coal
Secondary fuel Natural gas
Tertiary fuel Biofuel
Power generation
Nameplate capacity 3,360 MW
grid reference SU508919

Didcot Power Stations consist of an active natural-gas power plant (Didcot B Power Station) that supplies the National Grid, and a closed[1] combined coal and oil power plant (Didcot A Power Station). They are situated immediately adjoining each other in the civil parish of Sutton Courtenay, next to the town of Didcot in Oxfordshire, England.

A large section of the boiler house at Didcot A power station collapsed on 23 February 2016 while the building was being prepared for demolition. Four men were killed in the collapse.

The combined power stations feature a chimney which is one of the tallest structures in the UK, and three hyperbolic cooling towers (three others were demolished in 2014), which can be seen from much of the surrounding landscape.

Didcot A

History

Didcot A Power Station was a coal and gas-fired power station designed by architect Frederick Gibberd. Construction of the 2,000 MWe power station for the Central Electricity Generating Board began during 1964, and was completed in 1968 at a cost of £104m, with up to 2,400 workers being employed at peak times. It was located on a 300 acres (1.2 km2) site, formerly part of the Ministry of Defence Central Ordnance Depot. A vote was held in Didcot and surrounding villages on whether the power station should be built. There was strong opposition from Sutton Courtenay but the yes vote was carried, due to the number of jobs that would be created in the area.

The main chimney was 650 ft (200 m) tall[2] with the six cooling towers 375 ft (114 m)[3] each.

English Heritage declined to give listed building status to Didcot A Power Station in 2013. Though it recognised there were some interesting features, for example the "carefully designed" setting and Gibberd's detailing, there were better examples elsewhere.[4] The station ceased operation on 22 March 2013.

Operation

The station used four 500 MWe generating units. In 2003 Didcot A burnt 3.7Mt of coal. The station burned mostly pulverised coal, but also co-fired with natural gas. Didcot was the first large power station to be converted to have this function. In addition, a small amount of biomass, such as sawdust, was burned at the plant. This was introduced to try to depend more on renewable sources following the introduction of the Kyoto Protocol and, in April 2002, the Renewables Obligation. It was hoped that biomass could replace 2% of coal burnt. In 1996 and 1997, Thales UK was awarded contracts by Innogy plc (now RWE npower) to implement the APMS supervisory and control system on all of the four units, then enabling optimised emissions monitoring and reporting.[5] Between 2005 and 2007 Didcot installed overfire air systems on the four boilers to reduce emissions of nitrous oxide.This ensured compliance with the Large Combustion Plant Directive.

Some ash from Didcot A was used to manufacture building blocks at a factory on the adjacent Milton Park and transported to Thatcham (near Newbury, Berkshire) for the manufacture of Thermalite aerated breeze blocks using both decarbonized fly and raw ash, but most was mixed with water and pumped via a pipeline to former quarries in Radley.

Environmental protests

2006 Greenpeace Protest

On the morning of Thursday 2 November 2006, 30 Greenpeace trespassers invaded the power station. One group chained themselves to a broken coal-carrying conveyor belt. A second group scaled the 650 ft high chimney, and set up a 'climate camp'. They proceeded to paint "Blair's Legacy" on the side of the chimney overlooking the town. Greenpeace asserted that Didcot Power Station was the second most polluting in Britain after Drax in North Yorkshire,[6] whilst Friends of the Earth describe it as the ninth worst in the UK.[7]

A similar protest occurred early on 26 October 2009, when nine climate change protesters climbed the chimney,[2] and eleven chained themselves to the coal delivery conveyors; the latter group were cut free by police after five hours, but the former waited until 28 October before coming down again — all twenty were arrested, and power supplies continued uninterrupted. The power station was installing improved security fencing at the time.[8]

2013 closure

Didcot A opted out of the Large Combustion Plant Directive which meant it was only be allowed to run for up to 20,000 hours after 1 January 2008 and must close by 31 December 2015 at the latest. The decision was made not to install Flue Gas Desulphurisation equipment which would have allowed continued generation.

Studies did continue into whether there was a possibility that Didcot A might be modernised with new super-clean coal burning capabilities; with RWE partly involved in the study,[9] however in September 2012 RWE Npower announced that Didcot A using its current coal burning capabilities would close at the end of March 2013.[1] On 22 March 2013, Didcot A closed and the de-commissioning process began.

Demolition

The three southern cooling towers of Didcot A were demolished by explosives on Sunday 27 July 2014 at 05:01 BST. The contractors had insisted that the demolition would take place between 3 am and 5 am; the towers were demolished at 5.01am.[10][11]

There had been a campaign to move the time of the demolition to 6 a.m. or later to enable local people to watch the demolition,[12] but RWE refused. Despite the early morning demolition, many thousands of people turned out locally to watch from numerous vantage points, as well as those who watched the towers come down via a live Internet stream and the event trended heavily on Twitter with the hashtag #DidcotDemolition.[13]

2016 collapse

On 23 February 2016, a large section of the former boiler house at Didcot A power station collapsed while the building was being prepared for demolition.[14][15] One person was killed outright and three people were listed as missing presumed dead.[16] Four or five people were injured,[14][15] three seriously.[16] Additionally, around 50 people were treated for dust inhalation.[14] The rubble from the collapse was 9 metres (30 ft) high and unstable, which along with the instability of the remaining half of the building hampered search efforts.[16]

The collapse occurred at around 16:00 GMT, and Thames Valley Police declared a "major incident" shortly thereafter. Initial reports of an explosion were ruled out by police after being reported in the media for several hours following the incident.[14][15]

The boiler house was a steel framed building with the boilers suspended from the superstructure and above ground level to allow for their expansion.[4] At the time of the collapse it was being prepared for explosive demolition on 5 March, a process which involved cutting the structure to weaken it.[17]

On 17 July 2016, what remained of the structure was demolished in a controlled explosion. The bodies of the three missing men were still in the remains at that time. A spokesman said that due to the instability of the structure, they had been unable to recover the bodies. Robots were used to place the explosive charges due to the danger and the site was demolished just after 6 o'clock in the morning (BST). The families said that they wanted their dead relatives back in one piece, not hundreds of pieces but the demolition company highlighted the inherent danger of rescue operations citing that "legally you could not justify humans going back in."[18]

The search for the missing men continued the day after the controlled demolition. On 31 August 2016, it was confirmed that a body had been found in the rubble and the search had been paused to allow specialist teams to recover the body.[19]

On 6 September 2016 Police reported they believed to have found the body of one of the remaining two missing men. On 9 September, the body was formally identified as that of missing workman Ken Cresswell.

Rail Service

Similar to many power stations built at the time, Didcot is served by a rail loop which is a branch from the Great Western Main Line.[20] This allowed weekly coal and oil trains to service the Power Station. The loop has not been used since the Station's closure in 2013 and in its current state it is overgrown with vegetation. Initially the coal was supplied from the Nottingham coalfields then latterly from South Wales or Avonmouth when the Northern coal pits were closed. The service from South Wales was usually operated by one Class 66 pulling 25 EWS Coal Cars. The service ran from Avonmouth in Bristol, down the main line, reversing at Didcot Parkway and into the power station.[21]

Didcot B

History

Didcot B is the newer sibling initially owned by National Power, constructed from 1994-7 by Siemens and Atlantic Projects, and uses a (CCGT) type power plant to generate up to 1,360 MWe of electricity.[22] It opened in July 1997.

Specification

It consists of two 680 MWe modules, each with two 230 MW SGT5-4000F (former V94.3A) Siemens gas turbines and two heat recovery steam generators, built by International Combustion (since 1997 known as ABB Combustion Services Ltd), and a steam turbine.

Closure

Owners RWE announced on 9 January 2014 that modules 5 and 6 of Didcot B will cease generation by 31 December 2023 at the latest, to comply with the European Industrial Emissions Directive which takes effect as of January 2016. It is however possible that the life of these modules will be extended if RWE decide to install equipment to further reduce emissions of sulphur dioxide and nitrogen oxides.[23]

2014 Fire

On 19 October 2014, the cooling towers serving one of the steam turbines at Didcot B caught fire. Two of the fifteen fan-assisted cooling towers in the row were completely destroyed, one was seriously damaged, and one suffered light damage.[24] The cause was probably an electrical fault in one of the cooling fans.[25]

Ownership

Following privatisation of the CEGB in the early 1990s, Didcot A passed into the control of what became National Power, who also started construction of Didcot B. Following demerger the plant passed to Innogy plc (in 2000) and following the takover of Innogy by RWE in 2002 ownership passed to RWE npower.[3]

Architectural reception

Didcot Power Station viewed from Wittenham Clumps, prior to the demolition of Didcot A.

See also

References

  1. 1 2 "Didcot and Fawley power stations to close in March 2013". BBC News Online.
  2. 1 2 "Didcot Power Station protester guilty of trespass". BBC News. 13 May 2010. Retrieved 28 July 2014.
  3. 1 2 "Didcot Power Station celebrates 40th birthday". BBC News Online. 29 September 2010.
  4. 1 2 3 4 5 "List entry - Didcot A Power Station". English Heritage. Retrieved 22 July 2014.
  5. ↑ For more information, see Advanced Plant Management System, the Didcot A Case study on the APMS website or the article about the implementation of the Moore's Quadlog Safety PLC in Didcot.
  6. ↑ "Climate campaigners shut down one of UK's biggest power stations". Greenpeace. Retrieved 2 November 2006.
  7. ↑ "Carbon Dinosaurs". Friends of the Earth. Archived from the original on 19 October 2004.
  8. ↑ Sloan, Liam (29 October 2009). "Didcot tower is 'taken'". The Oxford Times. Oxford: Newsquest (Oxfordshire) Ltd: 3.
  9. ↑ "The Role of Coal in Electricity Generation". RWE.
  10. ↑ "Didcot power station towers demolished". BBC News.
  11. ↑ "Explosives demolish UK power station cooling towers". Reuters.
  12. ↑ Sam McGregor (30 June 2014). "Hundreds sign petition to change the time of Didcot towers explosion". Oxford Times.
  13. ↑ "Didcot demolition waves goodbye to historic power station towers". The Guardian. Retrieved 28 July 2014.
  14. 1 2 3 4 "Didcot Power Station collapse: One dead and three missing". BBC. Retrieved 23 February 2016.
  15. 1 2 3 "Power Station Demolition". Coleman and Company. Archived from the original on 23 February 2015.
  16. 1 2 3 "Three missing after Didcot collapse 'unlikely to be alive'". BBC. 24 February 2016. Retrieved 24 February 2016.
  17. ↑ Daniel Kemp (2 March 2016). "Mark Coleman: 'This must never happen again'". Construction News. Retrieved 4 March 2016.
  18. ↑ "Didcot Power Station: search to resume after demolition". BBC News. 17 July 2016. Retrieved 17 July 2016.
  19. ↑ "Didcot Power Station: Body found in rubble". BBC News. 31 August 2016. Retrieved 31 August 2016.
  20. ↑ Bridge, Mike (2010). Trackmaps 3: Western. Bradford-on-Avon: Trackmaps. p. 3C. ISBN 978-0-9549866-6-7.
  21. ↑ Shannon, Paul (2006). "Southern England". Rail freight since 1968 - Coal. Kettering: Silver Link. p. 38. ISBN 1-85794-263-9.
  22. ↑ Didcot B - RWE AG
  23. ↑ "RWE npower confirms plans to close UK coal power plant". Business Green.
  24. ↑ "Major fire at gas-fired Didcot B power station". BBC. Retrieved 19 October 2014.
  25. ↑ "Didcot B power station fire: Electrical fault probe". BBC News. Retrieved 11 July 2015.
  26. ↑ "Britain's Worst Eyesores". BBC News. 13 November 2003. Retrieved 4 November 2006.
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