Holding Slovenske elektrarne

Holding Slovenske elektrarne (HSE) is Slovenia's largest electricity producer, with its headquarters located in Ljubljana. The company's core activity is the generation of electrical power from a diversified portfolio of hydroelectric and thermal power plants situated throughout the country. Hydroelectric facilities constitute the majority of HSE's installed capacity, leveraging Slovenia's river systems for renewable energy production. Thermal units, primarily fueled by natural gas, provide dispatchable capacity that complements the variable output of hydro plants. The electricity produced by HSE is injected into the national transmission grid, supplying power to households, businesses and industrial consumers across Slovenia. Beyond generation, HSE participates actively in the wholesale electricity market, buying and selling power to balance supply and demand and to optimise its portfolio. The firm also offers ancillary services such as frequency regulation and reserve capacity, which contribute to the stability and reliability of the Slovenian power system. As a state‑owned enterprise, HSE is wholly owned by the Republic of Slovenia and operates under the legal framework governing public utilities.

HSE's generation output accounts for approximately sixty percent of Slovenia's total domestic electricity production, underscoring its pivotal role in the national energy mix. This substantial share classifies HSE as critical infrastructure, making it subject to heightened scrutiny from the Slovenian energy regulator, the Ministry of Infrastructure, and national cybersecurity authorities. The utility's distinguishing attributes include a strong reliance on renewable hydro resources, which help lower the carbon intensity of its generation portfolio compared to fossil‑fuel‑only producers. HSE's operational expertise in managing large‑scale hydro cascades enables it to provide flexible generation that can respond quickly to fluctuations in demand or supply. In November 2023, the company experienced a cyberattack involving crypto ransomware that temporarily affected its security and control systems, including fire alarms, although electricity generation continued without interruption. The incident triggered a coordinated response involving HSE's internal IT and security teams, external cybersecurity specialists, the Computer Emergency Response Team of Slovenia (CERT‑SI), law‑enforcement agencies and national security bodies. No ransom demand was made, and the attack did not disrupt the continuity of power supply, highlighting the resilience of HSE's operational controls and incident‑management procedures. Collectively, these facts establish HSE as a strategically important, state‑owned operator that balances renewable generation, market participation and critical‑infrastructure responsibilities within Slovenia's electricity sector.