Its goal is gradually replacing fossil fuels with low-carbon energy.

In the transition to low-carbon energy sources, nuclear energy plays an important role, Urška Dolinšek of the ministry said.

But safety must come first and nuclear waste must be disposed of in a responsible manner, she stressed.

The country would like to maximize its use of renewable energy sources such as hydro energy, biomass, solar energy, wind power, bio fuel and geothermal energy, and boost energy efficiency.

The most acceptable fossil fuel is gas, which is important for various industrial processes, while coal and lignite should no longer be used after 2055, according to Dolinšek.

The dependence on imports of petroleum products for transport should be halved by 2035, while heating oil should not be used after 2055.

The ministry sees transport as the most challenging area, consuming 40% of all energy used, mainly through imported petroleum products.

For greenhouse gases the goal is a 35% cut by 2035 and a 70% cut by 2055, the Infrastructure Ministry's official said.

The head of the energy directorate at the ministry, Daniel Levičar, sees electric cars as a key solution. The idea is to have at least a half of all vehicles powered by electricity by 2035 and the rest by 2055.

The costs of imported energy sources cannot be overlooked, according to him. Fossil fuel, mostly petroleum, cost the country about EUR 2bn in 2013. "That's the money that's lost for Slovenia," he said.

He believes the country could save EUR 1.2bn with the use of alternative fuels for transport.

A problem, however, will be to find a compensation for excise duties on fuel, currently a key source of budget revenue. Levičar sees excise duties on electricity as a possible solution.

The draft energy concept will provide the basis for Slovenia's energy policy in the next 20 years and a vision for the next 40, Infrastructure Minister Peter Gašperšič said.

The goal is a transition to a low-carbon society, but the energy sector must still serve the needs of both households and businesses, he added.

The three pillars of the energy concept are environmental sustainability, lowering of CO2 emission (by 80% until 2055), reliable supply and competitiveness, he said.

The ministry is collecting remarks by 15 August, while a blueprint should be ready by the end of the year, according to Gašperšič.

Greenpeace Slovenija criticised the proposal as "inadmissible in its bias in favour of nuclear energy," demanding that all energy technologies be compared and evaluated on equal footing.

"We are convinced that in this case you would pick rational energy use and renewables, including wind and solar" the organisation said.

It also wants the government to call a binding referendum before it takes a final decision on whether to built a second unit at the Krško Nuclear Power Plant.