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Nuclear energy in the UK

Nuclear electricity is a predictable and low-carbon part of the UK energy mix, currently providing 15% of the UK’s electricity. However, most existing nuclear power stations are set to close by 2030. The Government has an ambition to increase production of nuclear energy. One new nuclear power station is under construction (Hinkley Point C) and another (Sizewell C) has received planning consent. This POSTnote reviews the evidence surrounding the construction of new nuclear power stations and the ways in which nuclear might contribute to emission reduction targets.

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The proportion of electricity generated by nuclear power in the UK has declined since the 1990’s, with all nuclear power stations except one set to close by 2030. The Government has stated an ambition of up to 24 GW of new nuclear power stations by 2050, which will include the under-construction Hinkley Point C and proposed Sizewell C reactors. Beyond this though, the optimal potential contributions of current and proposed technologies is less clear, if required at all to help meet emissions reduction targets. 

Reactor designs currently available have experienced overruns in construction, which has contributed to significant underestimation of total cost. Nuclear developers claim that new designs will address this through improved manufacturing techniques. Designs using novel coolants also hold potential for decarbonising heat and hydrogen production. These will however require significant development and investment, which will likely take until 2030 at the very earliest. Financial mechanisms to minimise or share financial risk with consumers are also required to incentivise private investment. 

The greatly increased role of renewable energy in future electricity networks will increase the value of demand or supply side flexibility in helping to reduce overall costs to consumers. The ability of nuclear power to contribute to this is less clear, particularly under new financial support mechanisms. Local and national support, the provision of fuel, dealing with long-lived nuclear waste, and the trade-off with investment in other low-carbon technologies will all also need to be considered. Stakeholders have highlighted the essential role that committed Government support plays in determining the success of nuclear development. 

Key messages 

  • Globally, nuclear projects have tended to overrun in cost and time. 
  • New designs, which developers suggest could address historical issues, will require further development and not be available until at least the 2030s. 
  • Changes to the mix of electricity generation technologies will affect how nuclear can be integrated into the grid. 
  • Encouraging private investment requires mechanisms to reduce or share financial risk with consumers to minimise costs. 
  • Nuclear stakeholders suggest a Government supported programme of reactors could reduce investment risk for developers. 
  • There are concerns that over-emphasis on nuclear could divert investment and resources from other low-carbon technologies. 


POSTnotes are based on literature reviews and interviews with a range of stakeholders and are externally peer reviewed. POST would like to thank interviewees and peer reviewers for kindly giving up their time during the preparation of this briefing, including: 

  • Members of the POST board 
  • Sarah Beacock and Mark Salisbury, Nuclear Institute 
  • Andrew Bloodworth, British Geological Survey 
  • William Bodel and Gregg Butler, Dalton Institute 
  • Sarah Brown and Tim Parkes, Office for Nuclear Regulation 
  • Bruce Cairns and Neil Hyatt, Nuclear Waste Services 
  • Jo Campbell, National Infrastructure Commission 
  • Paul Dodds, University College London 
  • Paul Dorfman, University of Sussex 
  • Alison Downes, Stop Sizewell C 
  • Bridget Durning and John Glasson, Oxford Brookes University 
  • Alastair Evans and Ross Reid, Rolls-Royce SMR 
  • Steve Garwood, Imperial College London 
  • Robin Grimes and Will Watson, Imperial College London 
  • Sue Ion, Royal Academy of Engineering 
  • Giorgio Locatelli, Politecnico di Milano 
  • Adam Locke, Laing O’Rourke 
  • Richard Outram, Nuclear Free Local Authorities 
  • Doug Parr, Greenpeace 
  • Fiona Rayment, National Nuclear Laboratory 
  • Matt Rooney, Institute of Mechanical Engineers 
  • Steve Thomas, University of Greenwich 
  • Andy Storer, Nuclear Advanced Materials Research Centre 
  • Florian Wagner, BEIS 
  • James Whiteford, Dave Wagstaff and David Parfitt, National Grid ESO 
  • Ieuan Williams, Nuclear Industry Association 

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