Slovakia - Energy Sector Overview

Grid Map

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Key

Power Lines

22 kV
110 kV
220 kV
400 kV
Line reference
Underground

Power Plants

Hydroelectric
Hydroelectric
Nuclear
Nuclear
Oil/Gas
Oil/Gas
Wind
Wind

Overview

Energy sector structure

GENERATION

SEAS
State 34% • Private 66%
Other Generators
Various private and public
↓

TRANSMISSION

SEPS
State 100%
↓

DISTRIBUTION

ZSE
State 51% • Private 49%
SSE
State 51% • Private 49%
VSE
State 51% • Private 49%
Slovakia's energy sector is characterized by a mixed ownership structure established following market liberalization in 2005. The wholesale electricity market operates under deregulated pricing mechanisms, with cross-border trading volumes unrestricted since January 2005.
To comply with EU unbundling regulations, Slovakia separated the supply, transmission and distribution activities within the industry.
Slovenské elektrárne (SEAS) maintains the majority position in electricity generation with a 66% market share, supplying electricity to three major regional distribution companies: Západoslovenská energetika (ZSE), Stredoslovenská energetika (SSE), and Východoslovenská energetika (VSE).
The transmission of the electricity is under the responsibility of Slovenská elektrizačná prenosová sústava (SEPS)which operates the high voltage 400 kV and 220 kV lines, as well as selected 110 kV lines. Regional distributors control the rest of 110 kV, 22 kV and other minor lines.
SEPS is a wholly state-controlled company. The state also retains a minority 34% stake in SEAS. The distribution companies operate under a hybrid ownership model, with 51% state control and 49% private ownership held by international energy groups including E.ON, RWE Group, and EPH.

Capital formation in the energy sector

Fixed Capital Formation

Gross Fixed Capital Formation (GFCF) and Net Fixed Capital Formation (NFCF) for electricity, gas, steam and air conditioning supply sector, measured in million euros (2020 chain linked volumes).

Data source: Eurostat (NAMA_10_A64 and NAMA_10_A64_P5) | additional processing by Tomáš Bui
NFCF = GFCF - Consumption of Fixed Capital | Chain linked volumes (2020)
Licensed under CC BY 4.0.

Capital formation measures investment in energy sector infrastructure. These indicators reveal the sector's capacity for growth and modernization.
Gross Fixed Capital Formation (GFCF) refers to amount of investment in a sector including maintenance, replacement. When Consumption of Fixed Capital is subtracted, we get an approximate Net Fixed Capital Formation (NFCF):
Net Capital Formation=Gross Capital Formation−Consumption\text{Net Capital Formation} = \text{Gross Capital Formation} - \text{Consumption}
Slovakia's energy sector experienced significant investment peaks in 2006-2007, followed by varying cycles of capital deployment and asset depreciation through economic transitions.
As EU-wide Green New Deal climate action is rolled out, investment in nuclear energy and renewables accelerated, it is expected to see significant increases in both gross and net fixed capital formations.

Read more - TBA

Analysis of ÚHP financial report on theoretical new nuclear power plant.

Generation

Electricity generation

Electricity generation

Total electricity generated in Slovakia, measured in terawatt-hours.

Data source: Ember (2025) | Energy Institute – Statistical Review of World Energy (2024) | Our World in Data
Licensed under CC BY 4.0.

Electricity generation reflects a country's industrial capacity and energy infrastructure development. It serves as a key indicator of economic activity and technological advancement.
Total electricity generation encompasses all forms of power production including nuclear, fossil fuels, renewables, biomass and hydroelectric sources measured in terawatt-hours (TWh) to capture the massive scale of national power systems.
This interactive chart shows total electricity production by year, tracks energy trends and compares generation capacity across different time periods.
The data reveals patterns in energy policy, infrastructure investments, and the transition toward renewable sources in the national electricity mix.

Electricity generation by source

Nuclear power forms the backbone of Slovakia's electricity mix, generating about 18 TWh in absolute terms and 60% in relative terms of worth of electricity. Slovakia operates two plants - Bohunice and Mochovce.
The deployment of renewables is accelerating. However, as of 2025 Slovakia doesn't operate large scale wind or solar farms. Solar power accounts for about 2% of the electricity mix, with installations predominantly rooftop-mounted rather than utility scale.
Rounding the non-fossil fuel mix, Hydro power represents about 16% or 5 TWh in absolute terms. Slovakia operates various types of these plants including run-of-the-mill, water resevoirs and pumped storage plants
Slovakia shut down its last coal plant Vojany in 2024. The remaining electricity still generated from coal comes from heating plants. Gas power plants complement the energy mix with approximately 9% of total generation, primarily serving as flexible CHP plants or for industrial processes in the case of Slovnaft.
These chart shows total electricity production by year, track energy sources and compare generation capacity across different time periods.

Electricity generation by source

Data source: Ember (2025) | Energy Institute – Statistical Review of World Energy (2024) | Our World in Data
Licensed under CC BY 4.0.

Electricity generation share by source

Data source: Ember (2025) | Energy Institute – Statistical Review of World Energy (2024) | Our World in Data
Licensed under CC BY 4.0.

Installed capacity

Installed capacity represents the theoretical maximum electrical output that power infrastructure can deliver under optimal conditions, measured in megawatts (MW). The relationship between installed capacity and actual output varies dramatically across energy sources due to capacity factors.
Capacity factor measures the percentage of theoretical maximum output that a power source actually delivers over time, accounting for maintenance, fuel availability, and operational constraints.
CF=EactualPrated×T×100%CF = \frac{E_{\text{actual}}}{P_{\text{rated}} \times T} \times 100\%
For example, nuclear plants typically demonstrate the highest capacity factors (80-90%) due to their role as baseload power, operating continuously except during scheduled maintenance.
In contrast, renewable sources like solar and wind exhibit significantly lower capacity factors (15-35%) due to weather dependency and intermittency.

Important notes

Data covers multiple countries and was compiled from multiple sources including Energie Burgenland (Wind), Slovenské elektrárne (Nuclear-Hydro), Wikipedia (Solar-Coal-Gas)

  • •Installed MW data for solar is based on estimate from PV Magazine
  • •Hydropower capacity from plants of less than 5 MW are excluded
  • •Installed MWe of Gas/Coal/Biomass heating plants are excluded
  • •Data reflects different time periods due to source availability

Installed Capacity by Source

Data source: Various sources | additional processing by Tomáš Bui
Licensed under CC BY 4.0.

Installed capacity vs. Capacity factor

Data source: Various sources | additional processing by Tomáš Bui
Licensed under CC BY 4.0.

Share of electricity from fossil fuels

Fossil fuel share in electricity generation

Share of electricity generation from fossil fuels including coal, oil, and gas, measured as a percentage of total electricity generation.

Data source: Ember (2025) | Energy Institute – Statistical Review of World Energy (2024) | Our World in Data
Licensed under CC BY 4.0.

Slovakia maintains one of the cleanest and reliable energy sectorsin Europe alongside France, Finland, and Sweden. This is accomplished through combination of nuclear baseload and hydroelectric plants.
Slovakia reduced its fossil fuel dependency from 45.4% in 1990 to 14% in 2024, representing a 69% reduction over three decades.
This interactive chart shows evolution in electricity production by year of various countries, tracks energy trends and compares generation capacity across different time periods.

Transmission

Transmission lines

Transmission lines by voltage level

Length of transmission lines by voltage level, measured in kilometers.

Data source: Various SEPS annual reports | additional processing by Tomáš Bui
SEPS a. s.

Transmission infrastructure enables the transport of electricity from generation sources to distribution networks across the country and facilitates cross-border energy trade with neighboring states.
The 400 kV network represents the highest voltage level in Slovakia's grid, totaling approximately 2,357 kilometers and primarily handles bulk power transmission, international interconnections with neighboring countries including Czech Republic, Hungary, Poland, and Ukraine.
The 220 kV network comprises around 688 kilometers of lines, This network has seen gradual reduction over time as lines have been upgraded to 400 kV.
SEPS operates approximately 80 kilometers of 110 kV transmission lines, The majority of Slovakia's 110 kV infrastructure is managed by regional distribution companies as part of their local networks.

Important notes

Data excludes 110 kV and 22 kV operated by regional distributors numbered in thousands of kilometers.

Electricity trade balance

Electricity trade balance

Net electricity balance showing imports and exports, measured in gigawatt-hours (GWh).

Various SEPS annual reports | additional processing by Tomáš Bui
SEPS a. s.

Electricity trade balance refers to balance between net exports and imports of electricity. Due to the nature of electricity, countries may export or import depending on seasonal and structural needs.
Net Electricity Balance=Exports−Imports\text{Net Electricity Balance} = \text{Exports} - \text{Imports}
Slovakia transitioned from being a net importer in the mid-1990s to becoming a net exporter from 1999-2006. Following the closure of Bohunice units 1 and 2, the country reversed to being a net importer of 1,000-4,000 GWh annually.
Slovakia is poised to being a net exporter after Mochove unit 3 and 4 are built and fully functioning. In 2023, Slovakia achieved a positive trade balance of 3,422 GWh, marking its return to net exporter status after 17 years.