The war in Ukraine has turned against Russia and its authoritarian president, Vladimir Putin, with Ukrainian forces routing battered Russian units and retaking surprising amounts of turf in northeast Ukraine. But Putin still has some potent weapons he can deploy, and an energy war with the West is erupting in parallel with the military war in Ukraine.

Despite bruising sanctions, Russia remains the world’s third largest exporter of oil and natural gas, and in coming months, Putin seems very likely to test how much leverage that can provide against Ukraine’s American and European allies. Developed nations, led by the United States, are crafting a counteroffensive, to thwart Putin's effort to extort energy purchasers. Hundreds of millions of consumers are the potential collateral damage if Putin’s energy war inflicts the pain he intends, or the American-led blocking action backfires.

The most urgent threat is Russia’s throttling of natural gas to Europe. Russia has stopped gas flows through the Nord Stream pipeline, Europe’s single-biggest source of gas. It may halt other gas shipments, just as Europe needs the fuel for winter heat. Before the war, Russia provided about 40% of Europe’s gas. That's now down to about 9%. Despite aggressive weaning, Europe may simply not have enough gas this winter. European gas prices are six times higher than they were at this time last year and 14 times higher than they were two years ago.

European governments are considering price caps and other measures to limit the pain on consumers, but such measures have their own problems. A new UK price cap on household energy bills, for instance, undermines the incentive to conserve amid a supply shortage. That could cause the gas to simply run out.

“Price controls are going to encourage rather than discourage consumption, which means there are going to be blackouts,” Ed Morse, head of commodities research at Citigroup, said during a Sept. 9 webinar sponsored by the Brookings Institution. “The uncertainties around this winter are enormous. Winter in Europe is going to be the worst imaginable, in terms of power generation.”