In its newly published Winter Outlook 2022/2023, the National Grid electricity system operator (ESO) – which oversees the UK’s electricity grid – details different scenarios that could unfold if gas imports to Europe are reduced or if UK supplies run dry. The report warns that while ‘cautious action’ should be taken ahead of this winter to ensure security of electricity supply, the ‘Base Case’ scenario forecasts that there will be adequate margins and ‘sufficient operational service’ in the UK.

In this scenario it is predicted there will be roughly 3.7 GW more electricity than the country needs (less than three hours loss of load expectation), although it is expected that margins will be tightest throughout December to mid-January. The report also adds that it is highly likely that the wholesale price of both gas and electricity will remain very high throughout the winter outlook period (31 October 2022–31 March 2023).

While the Base Case scenario assumes that capacity across all providers (generation, storage, interconnection etc) is available in line with commitments secured under the capacity market, the ESO has also modelled a scenario whereby the energy crisis in Europe results in electricity not being available to import from continental Europe. This could be due to a combination of factors, including a shortage of gas in Europe (which in turn limits power generation in Europe) and/or generation unavailability (eg due to a high level of outages across another country’s generation fleet).

Under this ‘Alternate Scenario’ National Grid would need to deploy its planned mitigation strategies – which include dispatching five retained coal units that would have otherwise closed, generating an extra 2 GW of power – and introducing the ‘demand flexibility service’ (DFS), which incentivises users to reduce consumption at key times to reduce overall demand across the system. It is projected that this tool could reduce demand by a further 2 GW and enable the ESO to maintain adequate margins and mitigate impacts on customers.

Without deploying these planned mitigation strategies, National Grid says it would expect to see a reduction in margins and, on days when it is cold with low levels of wind, it may be necessary to interrupt supply to some customers for limited periods of time in a ‘managed and controlled manner’. However, the ESO states that it expects the suggested mitigations outlined above to be effective.

However, National Grid goes on to say that, in the unlikely event that escalation of the situation in Europe means that insufficient gas supply were to be available in the UK, leading to reduced electricity supply margins, there could be supply interruptions to customers for short periods. Under such a scenario, ‘all possible mitigating strategies would be deployed to minimise the disruption’.

Commenting on the report, Fintan Slye, Executive Director, National Grid, says: ‘Under our Base Case, we are cautiously confident that there will be adequate margins through the winter period. As an expert and responsible operator of Great Britain’s electricity system it is incumbent on us to also factor in external factors and risks beyond our control like the unprecedented turmoil and volatility in energy markets in Europe and beyond.’