The Commission is likely to publish the aggregate demand to attract buyers in early spring, Sefcovic said.

Some EU officials said certain large energy firms have expressed reluctance to join, since they can already negotiate their own gas deals and doubt the EU scheme will yield lower prices.

EU countries must ensure their local companies take part in the aggregation of gas demand, with volumes equivalent to 15% of the gas needed to fill that country's storage facilities to 90% of capacity.

EU-wide, the 15% requirement amounts to approximately 13.5 billion cubic meters of gas - a small fraction of the bloc's total gas imports, which totaled 338 billion cubic meters in 2021, according to Eurostat data.