Danish gas grid operator Energinet.dk said on April 20 it was speeding up a search for alternative gas supplies because of a risk that the country's largest offshore gas field could shut in two years.

A.P. Moller-Maersk has said it would shut its Tyra Field in October 2018 if production there becomes uneconomic due to a slump in oil prices.

"We are therefore investigating whether there is a need for alternatives ... there are several opportunities for expanding the gas transmission network, for example toward Norway or a Baltic pipe solution to Poland," the grid operator Energinet.dk said. "Analyses are now being accelerated."

Poland and Denmark were looking at possibly building a link to connect their gas grids, the Polish grid operator said in March.

"After 2018, gas customers in Denmark and Sweden will still have the gas they need," Energinet.dk Senior Vice President Torben Brabo said.

Denmark currently has enough capacity to meet demand at home and also for Sweden, by importing gas from Germany, but will need to expand its grid in the future, Energinet.dk said. Sweden gets all its gas from Denmark.

Denmark's annual gas output has halved over the last 10 years to less than 5 billion cubic meters per year, according to BP Plc's (NYSE: BP) annual statistics review. The Tyra complex produces around two thirds of Denmark's gas, according to Maersk Oil.

The Danish government has said it was prepared to look for ways to prolong Tyra's operations. The oil industry has previously proposed the introduction of tax credits on North Sea investments.

Maersk Oil operates Tyra Feld on behalf of the Danish Underground Consortium partnership, owned 31.2% by Maersk, 36.8% by Shell, 20% by Danish state-owned Nordsofonden and 12% by Chevron Corp. (NYSE: CVX).