The EU has appointed gas capacity platform Prisma to calculate countries’ collective demand for gas, as the bloc moves ahead with a plan to launch joint gas buying among member countries.

The European Commission hopes joint gas buying will help Europe to refill depleted storage caverns before next winter and to negotiate lower prices by using EU countries' collective buying power.

The European Commission last week signed a contract with Prisma, which is the EU's largest capacity booking platform for gas transmission, a Commission spokesperson told Reuters.

Prisma will be responsible for grouping together countries' gas import needs and seeking offers from gas suppliers to match those volumes.

Brussels wants countries to start their first joint gas purchases before summer and publish the amount of gas countries want to buy jointly in early spring, to attract supply offers.

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.

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