Neso data does not cover Northern Ireland, which has its own electricity transmission system operator, SONI.

The California Independent System Operator, which manages the state’s energy grid, said there was enough power statewide to meet demand.

A cold snap drove up consumption, forcing Ukrenergo, the main transmission system operator, to introduce controlled blackouts throughout the country.

"No system operator alone can win this battle; we need collaboration and system-wide assessments."

Finnish gas transmission system operator Gasgrid Finland estimated that the repair work would take at least five months.