Edinburgh-based Wood Mackenzie said the prospect of plummeting temperatures over coming months risked further depleting gas storage reserves across the continent down to just 4 per cent of their capacity by March.
The firm stressed a severe winter, coupled with further disruption to gas supplies from Russia, would have far-reaching repercussions, reducing supplies to less than two thirds of their capacity by the start of next winter.
In that scenario, the consultancy said such shortfalls would “inevitably” result in what is known as demand curtailments, meaning that energy use would be pared back to avoid blackouts.
The firm’s presentation of the worst-case scenario in its latest quarterly short-term assessment of European natural gas markets comes amidst heightened anxiety around energy supplies for this winter.
On Wednesday, Russia completely halted gas supplies to Europe via the Nord Stream 1 pipeline, with Gazprom, the state-owned energy giant, insisting the stoppage was necessary to carry out a three day-long programme of repair work.
Russia has already significantly reduced gas exports via the 745-mile long pipeline, which runs under the Baltic Sea from the Russian coast to north-east Germany. It has denied accusations it is using energy supplies as a weapon against Western countries.
The EU has already agreed to cut its gas consumption by 15 per cent until March in an attempt to stave off a winter crisis triggered by a sharp reduction or total shutdown of Russian gas supplies.
Foreign secretary Liz Truss, the clear favourite to become the next prime minister, has ruled out energy rationing this winter.
The Wood Mackenzie analysis makes clear that “reduced Russian flows” would have severe repercussions for Europe.
Massimo Di Odoardo, the firm’s vice-president of gas and liquefied natural gas (LNG) research, said: “Should Nord Stream flows not resume following September maintenance, European inventories might still end up at 26 per cent by the end of this winter, although they might only be able to get to 81 per cent ahead of next winter.”
But the biggest threat, Wood Mackenzie said, was the weather, with extremely cold conditions increasing the need for heating, and adding up to 30 billion cubic metres to winter demand. That outcome, it warned, could reduce European gas storage inventories to just 63 per cent by next winter, “resulting in demand curtailments”.
However, the company said that if the winter was mild, the situation would be markedly more positive.
Penny Leake, a research analyst for European gas, said: “Under normal weather conditions we anticipate a rebalance of the power market after winter, which, combined with an improved gas market balance, might see gas prices dropping by more than 35 per cent, trading closer to levels Europe had in late July.”
Mr Di Odoardo also said if Russian gas supplies via the Nord Stream pipeline resume at current levels after the maintenance work, he expected Europe “could be in a position to get through this and next winter without demand curtailments”.