Slovenia has only one nuclear power station; Krško Nuclear Power Plant (NEK) is located on the border with Croatia, and is co-owned by both countries.

NEK, which was launched in 1981 and produces a third of electricity generated in Slovenia, is planned for closure in 2043.

A debate on replacing it with a new reactor or renouncing nuclear energy altogether has been going on for more than 15 years.

The Janez Janša government included NEK 2 in a resolution on national development projects already in 2006, assessing it would cost EUR 2 billion and start being constructed in 2015.

The coalition agreement of the Marjan Šarec government speaks about renewable and reliable sources of energy, but does not mention nuclear energy, or NEK 2.

However, the Infrastructure Ministry has told the STA that in the emerging energy concept and in climate policy, nuclear energy is important from several aspects.

"Apart from being a low-carbon source of energy, it provides for a reliable supply of electricity at competitive prices, thus enhancing energy security," it says.

GEN Group, a state-owned company under whose wing is NEK, has already invested EUR 16 million into various studies on NEK 2.

The group has told the STA the project would build on all three basic guidelines of the EU and Slovenia's energy policy: climate sustainability, reliability and competitive energy supply.

If the state decides to build NEK 2, it would take five years to get a building permit and at least another five to complete construction work.

GEN Group estimates the investment at EUR 3.5-5 billion, depending on the technology chosen or the size of the reactor.

Leon Cizelj, head of the Jožef Stefan Institute's reactor engineering department, believes the state should decide to build NEK 2 as soon as possible.

He says nuclear energy is the only source of carbon-free energy that works day and night and in all weather conditions.

It is also ideal from the aspects of reliable energy supply and fight against the climate change, according to Cizelj.

If NEK 2 gets the green light, some 400-500 experts will have to be trained to monitor its construction and eventually work in the new facility, he says.

This will be according to Cizelj a key challenge since in Slovenia and most EU countries nuclear research and education is underfunded and understaffed.

But not everyone supports a new nuclear reactor, with many fearing disasters such as the ones in Chernobyl and Fukushima.

Opposition has also been expressed by the regional authorities in Austria's Carinthia, arguing NEK is located on a seismic fault and only 80 kilometres away.

But Cizelj begs to differ, saying "the data I have at my disposal show NEK is comparable to N-plants in the US and EU in practically all aspects, including safety".

Environmental NGOs are also against, with the Association of Ecological Movements of Slovenia arguing nuclear energy is not CO2 neutral as greenhouse gas emissions are generated in the production of uranium ore.

Both the Association and Greenpeace Slovenija want to see NEK closed as soon as possible to the benefit of other sources such as solar, wind or geothermal energy.

A referendum has also been mentioned as a way of deciding on this divisive issue.

Infrastructure Minister Alenka Bratušek has indicated that if the state decided on NEK 2 and citizens wanted to have a say, they should be given this option.