The European Commission has urged EU countries to reduce demand for natural gas by 15% over the coming months to secure winter stocks and defeat Russian "blackmail".
Announcing an emergency plan, EU commissioners also asked member states to give Brussels special powers to impose compulsory energy rationing if Russia cuts off Europe's gas lifeline.
A total shutdown of imports or a sharp reduction in the east to west flow could have a catastrophic effect on the European economy, shutting factories and forcing households to turn down the heat.
Last year, Russia represented 40% of the EU's total gas imports and any further disruption to supply would also push consumer prices higher and raise the risk of a deep recession.
"Russia is blackmailing us," European Commission President Ursula von der Leyen told reporters.
"Russia is using energy as a weapon and therefore, in any event, whether it's a partial major cut off of Russian gas or total cut off... Europe needs to be ready."
Russian President Vladimir Putin has played hot and cold in recent days with his threats to cut off gas deliveries to the bloc of 27 members, but Brussels is asking EU countries to prepare for the worst.
Since Moscow invaded Ukraine on 24 February and the West responded with sanctions, Russia has begun reducing its gas deliveries, apparently to prevent EU countries from replenishing reserves.
Europe is eagerly watching whether Russia will resume gas supplies via the Nord Stream 1 pipeline tomorrow when scheduled maintenance is due to be completed.
German pipeline manager Gascade said it expected Russian gas deliveries to resume at 40% of capacity, the level of supplies before maintenance work.
Mr Putin cast doubt today whether repair work conducted abroad on a compressor turbine would allow Russia to increase transit.
The EU has scrambled to replace Russian gas from farther-flung suppliers such as the United States, Norway, Azerbaijan and Algeria.
But the International Energy Agency warned on Monday that non-Russian gas resources "are simply not going to be enough".
According to the EU plan, each member state should "do its utmost" to reduce gas consumption by at least 15% between August 2022 and March 2023, compared to the average of the last five years over the same period.
By the end of September, countries will have to detail their roadmap for achieving this.
EU energy commissioner Kadri Simson also outlined a proposal, which like the rest of the package will have to be approved by member states, to give Brussels the powers to impose demand cuts.
"If the member states are not making sufficient progress, or the situation deteriorates, we propose that the commission can declare a state of EU alert at any moment," she said.
"This will trigger a mandate or obligation for the member states to meet the 15% cost reduction target."
There will be resistance among some EU capitals to mandatory measures.
But Ms von der Leyen told reporters the "binding phase" would only be triggered in the case of "a drastic reduction of Russian gas or a complete cut off of Russian gas".
The plan could be approved at an emergency meeting of energy ministers on Tuesday in Brussels, an EU official said.
The plan showed that the commission's main focus is on energy consumption by electric power companies and industry, since households make up only 37% of total gas demand.
Brussels also asks that states "switch to nuclear power where it is an option" and advises countries wishing to abandon atomic energy to postpone planned closures of nuclear power plants.
The EU's plans to survive the winter come amid increased concern over how badly a Russian gas crunch would affect the European economy in the coming months.
BusinessEurope, the EU's main business lobby, encouraged officials to stick to only "market-based" and voluntary solutions, warning that orders to stop or slow industrial energy use would be calamitous and should only be considered as "a last resort".
The plan will not include an energy price cap, an idea that has been strongly endorsed by the United States but that Europeans have so far excluded as a viable fix to their overdependence on Russia.
"This winter will be a test for the EU's energy system and for our union as a whole. And it is a test that we will pass if we act with solidarity and resolve," Simson said.
Meanwhile, Taoiseach Micheál Martin said that Ireland is not as reliant on Russian gas as other states, but if there are supply issues across the bloc it will impact prices on the Irish market.
When asked if Ireland should expect blackouts, Mr Martin said that discussions are under way at EU level in respect of the decisions taken around Russian energy.
"We do see issues with energy in terms of pricing certainly as we move into the autumn and supply in terms of the broader European experience."