Russian natural gas started flowing again through a crucial pipeline into Europe on Thursday, but Europe’s supply concerns remain amid the prospect of winter fuel shortages.

One day after Russian President Vladimir Putin promised to resume gas exports while still warning that supplies through the Nord Stream 1 pipeline may be further reduced, Thursday’s flows were back at 40% capacity, according to the pipeline’s numbers. European governments are bracing for permanent energy insecurity as Nord Stream deliveries remain at levels that are well below the pipeline’s maximum capacity.

The resumed Russian flows sent European natural-gas prices down by 5% Thursday to about $157.50 a megawatt-hour, according to Trading Economics. Prices fell by 14% over the past week but have more than doubled this year, and are four times higher than they were 12 months ago, causing energy costs to skyrocket.

Germany and other European Union countries that rely heavily on Russian gas imports are desperate to stockpile and save fuel for the winter, according to an emergency gas rationing plan put forth by the European Commission. The European Central Bank also announced on Thursday that economic activity is slowing in Europe as it moves to raise interest rates to combat compounding economic malaise amid high energy costs and inflation, according to a press release.

Deliveries were halted on July 11 due to annual maintenance, but sanctions and disputes over Russia’s invasion of Ukraine reduced deliveries to just 40% of the pipeline’s capacity, reported Reuters. Additionally, the war is cutting off pipeline routes in Ukraine and causing other supply chain issues.

Nord Stream referred the Daily Caller News Foundation to Thursday’s press release when asked for comment.