Prague  - Nuclear energy, a cheap and carbon-free source, could contribute to Europe's battle against climate change, European Commission President Jose Manuel Barroso said Thursday.

Nuclear energy "can help protect our economies against price volatility and reduce dependence on imported gas," Barroso told a nuclear-energy forum in Prague.

Barosso, however, said that the European Commission will not promote nuclear power to EU members who have "an absolute right to choose freely."

Some EU countries, such as Austria, fiercely oppose nuclear power. The commission's package of climate change and renewable energy proposals omits nuclear power.

Currently 15 members in the 27-member bloc generate power in nuclear reactors, Barroso said.

The Czech Republic and Slovakia, where such a conference was first held in November, have been pushing for a nuclear-power revival.

"It is clear to all of us that without nuclear we are unable to ensure energy security in Europe," Slovak Prime Minister Robert Fico said at a news conference.

Before entering the union in 2004, Slovakia was among several prospective members who made a commitment to close down its Soviet-era nuclear reactors.

Slovakia and Lithuania would now like to extend their operation in a bid that would require renegotiating their accession agreements and the approval of other member states.

"We have to stand by our commitments," Fico said. The only way out is "to reach a new agreement."

Slovakia agreed to close down two nuclear reactors at the Jaslovske Bohunice plant by 2009. The move will result in the central European booming economy importing 20 per cent of its energy, Fico said.

"We need realistic answers on how to secure such a large fallout that is awaiting us in 2009," he said.

According to Fico, the Jaslovske Bohunice plant was safe and business interests to build new plants in Slovakia were behind the upcoming closure.

Lithuania faces similar obstacles after shutting down its nuclear plant near a town of Ignalina at the end of 2009. Construction of a new nuclear plant is lagging behind. (dpa)