Slovenia’s energy system is defined by a balance that few European countries share. Nuclear power provides a stable source of low-carbon electricity, rivers flowing from the Alps support a large hydropower sector, and solar energy is expanding across homes and businesses. At the same time, the country still uses lignite for electricity, imports all of its petroleum products and depends on foreign natural gas.
This creates a complex energy transition. Slovenia must prepare for the closure of its remaining coal industry, modernize its electricity grid and reduce transport fuel use without weakening energy security. Its position between Central Europe, the Adriatic and the western Balkans also makes energy infrastructure important beyond Slovenia’s small domestic market.
Slovenia’s Energy Mix Reflects Both Independence and Import Dependence
Slovenia has more domestic energy resources than many small European countries. Nuclear energy, hydropower, biomass and lignite allow it to produce a significant part of the energy it consumes. However, the country remains dependent on imported oil, natural gas and electricity during periods when domestic generation is not sufficient or is more expensive than power available on regional markets.
Provisional figures for 2025 show that petroleum products supplied almost 35% of Slovenia’s primary energy. Nuclear energy provided almost one-quarter, renewable sources including hydropower supplied almost one-fifth, natural gas accounted for 13%, and coal provided slightly under 8%. Domestic sources covered 48% of national energy demand, while the remaining 52% was supplied through imports. All petroleum products were imported. [1]
The electricity sector has a different structure from the wider energy economy. Nuclear power and hydropower are the main pillars of electricity generation, while coal, solar power and smaller gas-fired plants provide the rest. This means Slovenia’s electricity is less dependent on fossil fuels than its transport, heating and industrial sectors.
The difference between electricity and total energy use is important. A country can produce relatively low-carbon electricity while still consuming large volumes of diesel, petrol, heating fuels and natural gas. Slovenia’s transition therefore depends on electrifying transport and heating as well as building new power plants.
Krško Nuclear Power Plant Sits at the Center of Slovenian Energy Policy
The Krško Nuclear Power Plant is the most important single electricity facility in Slovenia. Located near the Croatian border in the southeast of the country, the pressurized water reactor has a capacity of about 700 megawatts. It provides reliable output that does not depend on rainfall, sunshine or imported natural gas.
Krško is also an international energy project. The plant is jointly owned by Slovenian and Croatian partners, and its available electricity is divided equally between the two countries. As a result, the reactor generates electricity inside Slovenia, but only half of its output is counted as available to the Slovenian system under the bilateral arrangement. [2]
The plant has an unlimited operating permit under Slovenian law, but it must pass a detailed periodic safety review every ten years. Its most recent review supported continued operation during an extended operating period. Modernization projects have included safety improvements and a dry-storage facility for spent nuclear fuel.
The existing plant alone will not answer Slovenia’s longer-term electricity needs. The government and GEN energija are developing plans for a possible second nuclear project known as JEK2. A referendum planned for November 2024 was cancelled following political and legal disputes over the process and the information available to voters. The project itself continued.
In February 2026, the government formally began preparation of the National Spatial Plan for JEK2. This process covers the proposed reactor, linked infrastructure, environmental studies and impacts on protected areas. The government expects the spatial-planning decree to be completed in autumn 2028. A final investment decision would still require decisions on reactor size, technology, cost, financing, construction risk and public approval. [3]
For Slovenia, the debate is not simply about supporting or opposing nuclear energy. The country must decide whether a large new reactor is the best way to replace coal, support growing electricity use and reduce dependence on imports. It must also determine how JEK2 would operate alongside solar power, hydropower, storage and regional electricity trading.
Hydropower Connects Slovenia’s Rivers to Its Industrial Economy
Slovenia’s mountainous geography gives hydropower a central place in its energy system. The Drava, Sava and Soča river systems support a network of large and small hydroelectric plants. These facilities have supplied Slovenian homes and industries for decades and remain the country’s largest renewable electricity source.
Hydropower offers several advantages. It produces domestic electricity, reduces fossil fuel imports and can respond more quickly to changes in demand than a nuclear plant. Reservoir and pumped-storage facilities can also help balance the grid when solar generation rises or falls.
The 180-megawatt Avče pumped-storage plant is particularly important. During periods of lower demand or cheaper electricity, water can be pumped to an upper reservoir. It can then be released to generate power when demand and prices are higher. This type of storage becomes more valuable as Slovenia adds variable solar generation.
However, hydropower is exposed to weather and environmental limits. Dry conditions can reduce output, while floods can place pressure on dams, rivers and nearby communities. Slovenia’s rivers also pass through environmentally sensitive areas, making new projects politically and legally difficult.
Climate change adds another layer of uncertainty. Hydropower will remain a major Slovenian resource, but future output may become less predictable. Modernizing existing plants, improving water management and combining hydro with solar and storage may be easier than building dams on undeveloped sections of major rivers.
The Velenje Coal Region Is Entering Its Final Energy Chapter
Coal in Slovenia is concentrated around the Velenje lignite mine and the Šoštanj Thermal Power Plant, commonly known as TEŠ. This concentration makes the coal phaseout both simpler and more difficult. Slovenia is not dealing with many separate coal regions, but the remaining industry has deep economic and social importance in the Savinja-Šalek area.
The mine supplies lignite directly to Šoštanj, where Unit 6 has been the main generating unit. Coal production and thermal power have supported local employment, municipal income, technical skills and supply-chain businesses. More than 2,000 people have been directly employed by the mine and power plant, with additional jobs depending on the wider regional economy. [4]
Slovenia has committed to ending the use of coal for electricity generation by 2033 at the latest. The government has also been developing legislation for the gradual closure of the Velenje mine and the economic restructuring of the surrounding region.
The challenge is not limited to replacing megawatt-hours. The country must create new employment, retrain workers, manage mine closure, secure district heating and find new uses for industrial land and infrastructure. Slovenia’s earlier experience in the Zasavje coal region showed that mine closure can lead to long-term population and economic decline when replacement industries do not arrive quickly enough.
Coal’s share of Slovenian energy supply fell from around 12% in 2024 to below 8% in the provisional 2025 figures. The direction is clear, but coal generation may still change from year to year depending on hydropower conditions, nuclear maintenance, power prices and electricity imports. [1]
Oil Dependence Is Mainly a Transport and Logistics Problem
Slovenia is not an important oil producer, and official energy statistics show that its petroleum-product supply is fully imported. Oil therefore represents one of the clearest areas of foreign energy dependence.
Petroleum remains important because Slovenia has a highly mobile population, a developed motorway system and a strong transport and logistics sector. The country lies on major routes connecting Italy, Austria, Hungary, Croatia and southeastern Europe. Freight traffic, private cars, aviation and activity at the Port of Koper all support demand for diesel, petrol and other oil products.
In 2024, transport represented 42% of Slovenia’s final energy consumption. Manufacturing and construction used 24%, households 22%, service industries 9%, and other users the remaining 3%. Petroleum products made up 47% of all final energy consumption, compared with 23% for electricity, 14% for renewable energy and 12% for natural gas. [5]
These figures show why adding renewable electricity is not enough to transform Slovenia’s total energy system. Solar panels may reduce the use of coal or imported electricity, but they do not automatically replace diesel used by trucks crossing the country.
Electric vehicles can reduce oil demand among passenger cars, particularly when charged with nuclear, hydro or solar electricity. Rail investment could also move more freight and passenger travel away from roads. However, heavy transport, aviation and shipping will remain more difficult to electrify. Biofuels, hydrogen, synthetic fuels and more efficient logistics may therefore play supporting roles.
Natural Gas Links Slovenia to Three Neighboring Supply Systems
Slovenia produces little natural gas and relies on cross-border pipelines. Its transmission network is connected with Austria at Ceršak, Italy at Šempeter and Croatia at Rogatec. Some connections allow gas to move in both directions, giving suppliers several possible routes into the country. [6]
Natural gas provided 13% of Slovenia’s primary energy supply in 2025. It is used by industry, district heating systems, commercial buildings, households and combined heat-and-power plants. Gas can also provide flexible electricity generation when nuclear, hydro or solar power cannot meet demand.
The energy crisis that followed Russia’s invasion of Ukraine demonstrated the risks of relying heavily on one supplier or route. Slovenian companies responded by seeking alternative contracts and using supply routes connected with Italy, Austria and Croatia. Access to gas entering Europe through LNG terminals, including Croatia’s terminal on Krk, has become strategically important even though Slovenia does not operate its own large LNG import terminal.
The gas network may have a different role in the future. Plinovodi is studying infrastructure that could transport hydrogen or renewable gases between Croatia, Slovenia, Austria, Italy and eventually Hungary. Some existing pipelines could be adapted, while other sections would need to be rebuilt or expanded.
Whether these projects become economically important will depend on the future cost and availability of low-carbon hydrogen. In the near term, Slovenia’s main gas priorities remain diversified supply, reliable industrial service and lower consumption in buildings.
Solar Growth Is Changing Slovenia’s Renewable Energy Landscape
Hydropower remains Slovenia’s largest renewable electricity source, but solar energy has become the fastest-growing part of the sector. At the end of 2022, Slovenia had about 698 megawatts of installed solar capacity. More than 400 megawatts were added during 2023, taking the total to approximately 1,102 megawatts. [7]
Much of this development has come from rooftop and distributed solar rather than a few enormous desert-style projects. Homes, farms, warehouses, factories and public buildings can all host photovoltaic systems. This model fits Slovenia’s dispersed settlements and limited supply of open land, but it creates new technical demands for local distribution networks.
Solar production is highest during clear daytime periods, while household demand often peaks in the morning or evening. As more panels are installed, batteries, smart charging, flexible industrial use and stronger local grids become increasingly important. Hydropower and pumped storage can help, but they cannot solve every local congestion problem.
In 2024, renewable energy represented 24.64% of Slovenia’s gross final energy consumption before statistical adjustments. The renewable share reached 43.08% in electricity, 33.66% in heating and cooling, and 9.24% in transport. Slovenia used a statistical transfer of 207 gigawatt-hours of renewable energy from Croatia to reach its binding overall target of 25%. [8]
The transfer showed both progress and a remaining gap. Slovenia had moved close to the target through domestic activity, but renewable growth was not yet fast enough across the entire economy.
Wind power remains much smaller than hydro or solar. Mountain ridges may have useful wind conditions, but protected landscapes, settlement patterns, environmental reviews and local opposition can make large projects difficult. Slovenia’s renewable transition is therefore likely to remain centered on solar, hydropower, wood biomass, heat pumps and energy efficiency rather than a very large wind industry.
Forests, Wood Heating and the Energy Life of Slovenian Homes
Slovenia’s forests influence its energy system as well as its landscape and culture. Wood remains an important heating fuel, especially in rural homes and smaller settlements that are not connected to natural gas or district-heating networks.
In 2024, space heating accounted for 60% of household energy consumption. Electricity supplied 35% of household energy, while wood fuels supplied 33%. Heating oil, natural gas, heat pumps and district heating made up most of the remaining demand. [5]
Wood energy can reduce dependence on imported fossil fuels, but its environmental value depends on forest management and the efficiency of boilers and stoves. Old equipment can produce significant local air pollution. Modern biomass systems and efficient district-heating plants can use fuel more effectively, but they require investment and reliable fuel standards.
Heat pumps are likely to take a larger role, particularly in renovated buildings. They move household heating demand toward the electricity system, where nuclear, hydro and solar power can reduce emissions. This also increases winter electricity demand, strengthening the case for grid upgrades and firm generation.
Slovenia’s Grid Is Both a National System and a European Transit Route
Slovenia’s electricity grid is small in absolute terms but strategically located. Power can move across the country between the markets of Central Europe, Italy and southeastern Europe. The transmission system must therefore manage domestic consumption as well as international flows that may have little connection to Slovenian demand.
At the end of 2023, large generating units connected to the transmission network included 696 megawatts of nuclear capacity, 1,349 megawatts of thermal capacity, 1,009 megawatts of conventional hydropower and 180 megawatts of pumped storage. Distributed solar and other smaller facilities add capacity mainly through lower-voltage networks. [2]
Slovenia normally participates in both electricity imports and exports. According to ELES, the annual domestic electricity deficit has generally ranged between 7% and 30%, depending on hydrology, nuclear outages, coal availability, market prices and demand. In 2023, the calculated deficit was 9%, and Slovenia imported electricity during 63% of the hours in the year. [2]
This does not mean the country faces a physical shortage during every importing hour. Electricity is traded according to price as well as need. Slovenian generators may reduce output when imports are cheaper, while the country may export during periods of high hydro, nuclear or solar production.
Future grid investment must serve several changes at once. Solar power is becoming more decentralized. Heat pumps and electric vehicles will increase demand on local networks. Coal generation will disappear. JEK2, if built, would add a very large source at one location. Cross-border trade will also continue to grow.
The central infrastructure task is therefore flexibility. Slovenia needs stronger transmission routes, modern distribution equipment, digital control systems, storage and demand-response programs that encourage consumers to shift electricity use to periods of high supply.
Slovenia’s 2030 Energy Targets Depend on Faster Delivery
Slovenia’s updated National Energy and Climate Plan sets a target of at least 33% renewable energy in gross final consumption by 2030. Supporting targets include a 55% renewable share in electricity, 45% in heating and cooling, and 26% in transport. The plan also aims to keep final energy consumption at or below 4,320 kilotonnes of oil equivalent in 2030. [9]
Reaching these targets will require more than installing solar panels. Slovenia must accelerate building renovation, heat-pump adoption, public transport, vehicle electrification, industrial efficiency, storage and grid development. It must also complete the coal transition while keeping power affordable and reliable.
Nuclear energy will remain central during this period. The existing Krško plant provides firm electricity as coal declines. JEK2 is a longer-term decision, because a reactor of that scale cannot be planned and built quickly. Slovenia will need other investments before a second unit could enter operation.
The country’s future energy mix is likely to rest on four connected foundations: existing nuclear power, modernized hydropower, a much larger solar sector and close integration with neighboring electricity markets. Biomass, heat pumps, batteries, pumped storage and flexible gas capacity will support that system.
Slovenia’s main energy question is not whether it should choose nuclear power or renewable energy. Its strategy is moving toward both. The harder question is whether the country can build grids, storage, transport systems and political support quickly enough to connect them while coal closes and electricity demand rises.
