The Cattenom nuclear power plant in eastern France | Christophe Verhaegen/AFP via Getty Images EU energy solidarity left out in the cold The energy union is meant to have countries help each other, but national interests are stronger.

Plunging temperatures this winter left Bulgarians freezing, but when they asked neighboring Romania for extra electricity they got a short answer: No.

The January rejection came despite longstanding EU pressure for countries to help each other out in times of energy emergencies — though the evidence suggests they still prefer to look after their own people first. This nationally minded view of crisis management poses a huge challenge for the future success of the energy union program, one of the signature proposals of European Commission President Jean-Claude Juncker.

Countries’ behavior during this cold season gives a good taste of the challenge awaiting EU country officials over the next months as they begin dissecting a recent Commission proposal that would like to see governments working closer together in case of a power crisis.

Several governments halted electricity exports in recent weeks as they tried to deal with growing demand for power at home. With the chill set to linger, authorities and operators are choosing domestic customers over helping foreigners.

That makes sense politically: The people voting in the next election could punish a politician for short-changing domestic users to help neighbors.

One of the problems is that countries still tend to act on national and not EU interests, Commission Vice President Maroš Šefčovič told POLITICO.

Romania's government came up with a one-month emergency plan that allows the country to cut its energy exports if needed.

“There’s this historic divide that we need to overcome,” he said. “National reflexes, when it comes to policy and decision-making, especially in tense situations, are still there.”

That's the calculation that took place in Bucharest.

"Considering the delicate situation Romania finds itself in, we couldn't take this on and we told them [Bulgaria] that we cannot help them," said Romanian Energy Minister Toma Petcu, according to Romanian media.

Romania's decision isn't unique. Bulgaria also stopped power exports, as did Greece.

Romania's government also came up with a one-month emergency plan that allows the country to cut its energy exports if needed.

"Any country that respects its population puts its safety ahead of any margin of profit," Petcu said.

This behavior is the opposite of what the Commission’s energy union project envisions. The union is supposed to allow electricity and gas to flow freely from Bulgaria to Ireland, and for countries to rely on each other in the event of a crisis.

The most recent proposed law on emergency electricity plans sets out methods to ensure countries are prepared in case of a power crisis and spells out measures they should use to cooperate with each other. One of the goals is to ensure that even in a crisis "electricity is delivered where it is needed most,” according to the document.

The Commission had found in a prior assessment that “crisis plans and actions remain solely national in focus” and that “there is a lack of information-sharing and transparency.”

There is also a problem that selfishness on the part of one country could lead to problems elsewhere, creating instabilities in connected power grids.

"It is always the crisis-driven response that is forcing politicians to go back to their domains and say ‘We need to look after our own’” — Frederik Dahlmann, Warwick Business School

"Even incidents that start locally may rapidly spread across borders," the Commission warned.

But without closer coordination mandated by Brussels, there is no way countries can reliably count on each other, Šefčovič said. “It is quite clear that if you are in an emergency situation and you feel you can rely only on yourself, very often your only recourse is to look after your own country.”

Negotiations over a similar proposal on gas security measures have also run into difficulties, as some countries bridle at being forced to send gas to help foreign residential customers instead of supplying their own industrial users.

“We need to convince member states … that when it comes to an emergency situation … your neighbors in the EU should be there to help you,” Šefčovič said.

The debate between national interests and a broader solidarity is mirrored in other areas, ranging from dealing with migration, to financial regulation and terrorism, said Frederik Dahlmann, assistant professor of global energy at the Warwick Business School in the U.K. “Any crisis that landed on politicians’ desks … has strengthened a belief in national approaches.”

As the spat between Romania and Bulgaria shows, there is a disconnect between what the EU wants to achieve and politicians being accountable to their national electorates.

“The heart of the problem is who is holding power,” said Dahlmann. “There’s the long-term view that … we need much more coordination, but at the same time it is always the crisis-driven response that is forcing politicians to go back to their domains and say ‘We need to look after our own.’”

This article has been updated to clarify that the request came in January.