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Who put the lights out?


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The challenge of maintaining electricity supply in a Scotland outside the United Kingdom

SCOTLAND MATTERS, the non-party campaign for Scotland to remain in the United Kingdom commissioned a report into the ability of a Scotland outside the United Kingdom to maintain a secure supply of power. Entitled “Who put the lights out?” the report (downloadable here) provides a technically-based analysis of how a separate Scotland would face huge existential challenges to meet its domestic electricity demands, using 2025 as a baseline.

The report was researched and written by Paul Spare, a retired Safety and Decommissioning consultant who worked for almost 30 years in the nuclear industry for organisations such as NNC, UKAEA, Nuclear Technologies and W.S. Atkins.

Its conclusions are that continued integration and level of service with the National Grid of the continuing United Kingdom would be vital for Scotland. Without negotiating a mutually beneficial arrangement Scotland could not guarantee producing enough conventional energy to meet peak winter demands. This would require huge infrastructure investment to receive power from England when the wind is not blowing in Scotland and enable Scottish wind energy to be exported to England, while up to £1 Billion of renewable energy subsidy payments would have to be taken on by Scotland.

Existing wind turbines would not be assured of being able to deliver their power to the English market and could become worthless stranded assets.

For a new, independent Scottish state, reaching an agreement on conditions and costs would be complex and lengthy.

The SNP and Scottish Greens relentlessly boast about how they lead the world on climate change. The reality is they delivered only 21,000 of their 2010 forecast of 130,000 “green” jobs by 2021, failed to deliver their national cheap energy company and have repeatedly missed targets on emissions, wildlife preservations and recycling.

In the SNP’s 2014 Scotland’s Future manifesto for independence the issue of electricity supply was brushed off with the following one-sided assumption (page 237), “a single GB-wide market for electricity and gas will continue, with the current market trading arrangements, provided that they meet Scottish requirements for energy security supply”

Clearly it will not be as easy as that and secure energy supply through the UK National Grid now joins unknown currency, a hard border, the scale of the debt and deficit, EU and NATO membership as the great unanswered questions of the independence debate. The list only ever gets bigger.

The Executive Summary of the report follows with a link to the full report which can be downloaded in PDF. Scotland Matters website also hosts evidence for SNP claims around the climate issue that remain unmet: https://www.scotlandmatters.co.uk/metzero/

Executive summary

  • A National Grid providing continuous reliable power for 24 hours of all 365 days of the year across the British mainland of Scotland, England and Wales was established in the 1920s.
  • The grid has been able to meet the variable demands irrespective of locations between John O’Groats to Lands End by being fully integrated and operates from its Wokingham Centre in England.
  • For a Scottish national grid to be truly ‘independent’ and self-sufficient it would have to be able to provide its customers the same highly secure and reliable electricity supply all 365 days of the year – without being significantly dependent upon another country.
  • A Scottish national grid must also be able to provide a service over a wide range of conditions, from low summer to peak winter requirements, and cope with unanticipated demands and ‘loss of supply’ shocks.
  • Scotland’s current contribution to the National Grid can be up to 12500 MW of which 2400 MW is nuclear power and 1500 MW is Gas. A variety of renewable sources can provide 8600 MW of which 7000 MW relies on wind turbines.
  • Average demand in Scotland is about 3500 MW with a midwinter peak of 6000 MW meaning there is capacity available for ‘export’ to England through interconnectors that can cope with 5750 MW.
  • Technical aspects of the current National Grid and the sources of power generation will have a significant impact on any separate Scottish grid.
  • The National Grid’s “Electricity Ten Year Statement” of November 2019 ETYS stated: “The rapidly increasing generation capacity, mostly from renewable sources and mainly wind, connecting within Scotland is leading to growing needs in some areas.  Across all the scenarios, the fossil fuel generating capacity in Scotland reaches nearly zero.”
  • ETYS also noted… “although gross demand in Scotland is not expected to exceed 6 GW, at times of low renewable output Scotland may need to import power from England.  The present inter-connectors should be sufficient, but a Scottish grid might have to strengthen the South [England]-to-North [Scotland] equipment.” [our emphasis in bold]
  • New transmission routes are required.  The expanded (and still expanding) Scottish wind industry will have no market without new transmission lines to England.  The recently constructed Hunterston DC link was a £1 bn joint venture between National Grid and Scottish networks.
  • There is a real danger that Scottish wind turbines could become stranded assets; If the England and Wales grid is separated from Scotland there would be little incentive for National Grid to pay for a further interconnector when supplies could instead come from generators in England that would require less expensive investment.
  • The ETYS report also argued the Peterhead Gas Power Station had to remain in service if secure supplies were to be ensured in Scotland due to the unreliable nature of renewable generation.
  • Such problems can be managed while Scotland benefits from the availability of English generators connected to the UK grid.
  • Writing in Engineering and Technology magazine, David Watson, argued that by depending on so much uncontrollable renewable power starting the whole grid up following any collapse could take up to five days and only then with input from generators in England – and that a stand-alone Scottish grid, with the present mixture of power sources would be unstable.
  • In August 2019 a power cut was caused by a lightning strike affecting one million consumers through loss of 150 MW, then two large power stations, Hornsea One wind farm (737 MW) and Little Barford gas-fired (690 MW) caused a plunge in mains frequency and subsequent disconnections. Two of the owners made a voluntary payment of £4.5 million each into Ofgem’s redress fund.
  • By 2025 National Grid envisages an expansion of installed capacity in Scotland to at least 15000 MW.  Hunterston B would, however, have closed so Torness alone would be required for base load with Peterhead retained to stabilise supply.  Wind turbines would have expanded from 7000 MW TO 12000 MW.
  • If Scotland had its own separate National Grid then wind output would be greater than the conventional plant by a factor of four.  In certain weather conditions it would be impossible to balance the varying output from the wind sector because of the few controllable resources.
  • At the other extreme, with Torness and Peterhead being the only full scale secure supplies, providing 6000 MW would probably be impossible on a cold winter’s day with likely low wind speed.
  • The two foregoing catastrophic scenarios would be magnified if electric vehicle numbers increase quickly – and longer term if gas heating is phased out in favour of electric alternatives.
  • In 2020, Scotland produced 23.2 TWh amounting to 35% of UK wind energy of 65 TWh.  Estimates for UK renewable subsidies in 2019-20 are £9 Billion, with Scotland receiving about £3bn of that.
  • The cost to consumers of Scottish Renewable Obligation Certificates (ROCs) is estimated at £1.37bn with wind costing Scottish consumers about £1bn. The interruption of these substantial income streams would be highly destructive.
  • By 2025 England may continue to require to import 5000 MW, but also might prefer to import continuous, reliable supplies via the European inter-connectors.  It may decline against the more expensive, variable wind power from Scotland making the income absent and unavailable to Scotland.
  • Grid network strengthening will be required from the north coast down to the border before any new renewable power plants can export electricity to the English grid, costing many hundreds of millions of pounds.  The 200km-long Beauly-Denny 400 kV link cost £1 billion for a capacity of 1200 MW.
  • If Scotland seceded then the English electricity market would not be obliged to take its existing supplies but could renegotiate, making purchase decisions based on their own commercial interests.


  • An independent Scottish Grid is non-viable on the above evidence.  Separating Scotland from the stabilising effect of the much larger UK National Grid would almost certainly weaken the network beyond recovery.
  • Substantial Scottish investment will be required on north-to-south interconnectors to enable the electricity from any new wind farms to be fed towards the border with England.
  • Closing conventional power stations such as Peterhead and Torness at the same time as increasing the number of wind turbines will risk serious instability and lengthy power cuts. Electric cars and heating will only worsen a bad situation.  At times of low wind, all generation would be required to meet Scottish demand, leaving none for export.
  • If Scotland left the UK, there would be no obligation for suppliers in England to buy renewable power under the ROC or related schemes.
  • In addition, National Grid’s commercial strength would enable it to dominate any contractual negotiations between the two parties because of the unpredictable nature of the wind power Scotland had to sell.
  • If separated from the UK National Grid, an equivalent government subsidy would have to be established from Scottish consumers to owners of renewables.  Since there is a disproportionate concentration of wind farms in Scotland, the cost per capita to households could be three times that levied across the UK.

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Download a PDF of the report here


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