When could blackouts happen in UK? Exact time of day a 3 hour planned power blackout could occur this winter

The head of the UK’s electricity and gas systems’ operator has outlined the “worst case scenario” which could see UK households facing three-hour blackouts this winter.

National Grid boss John Pettigrew said blackouts would have to be imposed in the “deepest darkest evenings” in January and February if electricity generators did not have enough gas to meet demand, particularly if there is a bout of cold weather.

Pettigrew was speaking at the Financial Times’ Energy Transition Summit on Monday (17 October) when he made the grave prediction, although he remained confident that scheduled blackouts will not be needed.

His comments come after the National Grid issued a warning earlier this month that planned blackouts could be imposed in some areas, in the “unlikely” event supplies of gas fall short of demand.

Why could households face blackouts this winter?

Due to Russia’s war in Ukraine and sanctions on Russian gas imports, many European countries are facing gas shortages.

A large amount of electricity is generated from gas, putting strain on national electricity supplies as demand increases as the weather gets colder. The UK gets 40% of its electricity from gas-fired power stations while gas heats the vast majority of homes.

The UK does not rely on imported gas from Russia but it does import electricity and gas from European countries that rely on Russian gas, and this supply could be limited due to strained relations with the Kremlin.

In the face of the “challenging” winter facing European energy supplies following Russia’s invasion of Ukraine, the National Grid Electricity System Operator (ESO) is planning for what would happen if there were no imports of electricity from Europe.

To tackle a loss of imports from France, Belgium and the Netherlands, there are two gigawatts of coal-fired power plants on standby to fire up if needed to meet demand.

The ESO has warned that UK households and businesses may face planned three-hour outages during the winter to ensure the grid does not collapse.

The planned blackouts is the most dire of three possible scenarios that the ESO has set out for how Britain’s electricity grid might cope with the worst global energy crisis for decades.

In the other two scenarios, the operator hopes that by paying people to charge their electric cars at off-peak times, and firing up back-up coal plants, it can offset the risk of blackouts.

The lights will stay on this winter unless the gas-fired power plants that produced 43% of Britain’s electricity over the last year cannot get enough gas to continue operating.

The margins between peak demand and power supply are expected to be sufficient and similar to recent years in the National Grid ESO’s base case scenario for this winter.

What time of day could blackouts be imposed?

Pettigrew has told households to prepare for blackouts between 4pm and 7pm on weekdays during “really, really cold” days in January and February if gas imports are reduced.

The National Grid boss said he is confident this will not be the case, but added: “In the context of the terrible things that are going on in Ukraine and the consequences of that [it was] right that we set out what some of the potential risks could be."

It marks the first time since the initial warning from the ESO that there has been explicit discussion of what time blackouts may take place.

Any plans for scheduled power cuts will need to be approved by the government and King Charles before it could come into fruition.

Are there any plans to help prevent blackouts?

The National Grid plans to create a demand flexibility service, set to come in next month, that will offer financial incentives for switching energy usage to off-peak hours.

It means that people could be paid to run their washing machines at night, or charge their electric cars away from times of high demand.

The money-back service is to be implemented by energy suppliers and monitored using a smart meter, with a minimum reward of £10 per day being issued to households who prioritise off-peak electricity usage, according to the Mail Online.

The voluntary scheme is scheduled to run from November to March.Without it there could be cold and still days creating high demand and low levels of wind power, meaning there may be a need to interrupt supply to some customers for limited periods, National Grid ESO’s winter outlook said.