It will be a pricy affair for a number of Danish companies if Russia suddenly decides to shut down gas exports to the EU as part of the ongoing Ukraine crisis.

Denmark is actually gas self-sufficient but is obliged to provide other EU nations with its gas supply in case of a Russian embargo, national energy agency Energistyrelsen announced last week.

Among the 25 companies that would be hardest hit by the gas shut-down are Arla Foods, Carlsberg, Danfoss, Cheminova and Haldor Topsøe.

"If a situation like that occurs, we risk getting cut off from our gas supply," Jens Bakke, the head of public relations at Carlsberg brewery, told DR Nyheder.

Oil won't be enough
Denmark will cut off the supply to Danish companies with only a three-day warning.

"Then we will have to switch to oil, which would obviously be more expensive for us." Bakke said. "Oil will only cover 97 percent of our production, so we will still have to look for an alternative option."

Very few European countries are self-sufficient and the EU may quickly face a critical shortage if Russia shuts down its gas supply.