The debate on a second reactor gained momentum in August as PM Marjan Šarec visited NEK, the only N-plant and one of the biggest electricity producers in Slovenia, unequivocally supporting the country's nuclear energy future.

Strongly in favour of a second reactor, NEK and its Slovenian owner GEN Group understand Šarec's statement as support for their plans, even as some media have suggested it was meant primarily to test public opinion.

A debate on whether to replace the Slovenia-Croatia owned NEK with a new reactor, usually referred to as NEK 2, or renounce nuclear energy has been going on for over 15 years.

The Janez Janša government listed NEK 2 among national development projects in 2006, assessing its cost at EUR 2 billion and construction work launch in 2015.

GEN Energija has already invested EUR 16 million in various studies on NEK 2, but the coalition agreement of Šarec's government does not even mention nuclear energy in the first place, let alone an expansion.

GEN Energija estimates the investment at EUR 3.5-5 billion, depending on the technology chosen and the size of the new reactor.

The country's long-overdue energy concept, a keystone document laying out national energy policy until 2060, is expected to make the stance on a second nuclear reactor clear.

The Infrastructure Ministry points to the advantages of nuclear energy as a low-carbon and reliable source enhancing energy security, but still notes nothing has been decided yet.

Slovenia has reliable energy supply for the time being and would like to be as self-sufficient as possible, with energy consumption expected to further rise.

Statistics show that in 2018, Slovenia met 52% of its energy needs with own sources, and of the 148,000 terajoules in total energy output, NEK accounted for 42%.

Energy managers and nuclear scientists agree hydro-power stations will not suffice to replace NEK and coal-fired TEŠ, the country's two largest power stations, after 2040 when they are both expected to close.

Experts have also warned that without nuclear energy, Slovenia will have a hard time meeting the goals from its emerging 2021-2030 National Energy and Climate Plan.

Data for 2018 shows renewables accounted for 21.14% of the country's gross end energy use, which features all three energy sectors - transport, heating and cooling, and electricity. The EU's target for 2020 is 25%, which the Infrastructure Ministry says Slovenia is unlikely to achieve.

Under the draft plan, Slovenia would raise the share to 22.4% under scenario which takes into account "the existing measures". A scenario with "additional measures" puts the share at 24.1% and the "ambitious" one at 28.8%.

The Association of Slovenian Nuclear Scientists criticises the document for favouring natural gas-powered power stations to achieve decarbonisation goals, which it says would raise electricity prices and expose Slovenian citizens to the risk of energy poverty.

It believes Slovenia should not only build a new nuclear power station, but also extend the lifespan of NEK, which was launched in the early 1980s.

Yet not everyone supports a new nuclear reactor, with many fearing disasters such as Chernobyl and Fukushima and pushing for closing NEK as soon as possible.

Šarec's statement was strongly condemned by the regional authorities in Austria's Carinthia and environmental NGOs advocate the use of solar, wind or geothermal energy.

An NGO went as far as suggesting Slovenia should reduce energy consumption by at least a third before any consideration of new energy sources is made, while calls to politicians to present very precise information and serious alternatives in a decent debate could also be heard.