Model-based comparison of nuclear and renewable energy based strategies for slovenia

Končar, Mihael Boštjan (author), Hojkar, Domen (author), Drobnič, Boštjan (author), Sekavčnik, Mihael (author), Mori, Mitja (artist)

Decarbonising the primary energy sector is essential for achieving a sustainable electricity supply and requires a transition away from fossil fuels. Coal- and gas-fired plants are expected to remain only as strategic reserves, operating during emergencies or other critical situations. Two development strategies defined in Slovenia’s National Energy and Climate Plan are evaluated: a nuclear-based pathway and a renewable-only pathway. A zero-dimensional energy system model with hourly resolution was applied, integrating nuclear, thermal, hydro, wind, solar, and pumped hydro storage to represent projected 2040 conditions. System performance was assessed through grid stability, carbon intensity, import dependency, and spatial efficiency. The nuclear pathway provided stable baseload generation, minimised fluctuations, and reduced reliance on storage and imports. It achieved 113 kgCO₂eq/MWh with land use of 2.4 km²/TWh. The renewable-only pathway showed high variability, surpluses exceeding several gigawatts, and greater balancing needs, resulting in 148 kgCO₂eq/MWh and land use of 9.1 km²/TWh. An additional, nuclear-only variant further demonstrated that one reactor can replace several gigawatts of solar capacity while maintaining stability and reducing emissions. The results question the relevance and feasibility of renewable-only strategies and confirm the crucial role of nuclear power in ensuring secure, low-carbon electricity supply.

• Language: English
• Keywords: energy transition, energy system modelling, energy flows, environmental impact analysis
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 5 str.
• Numbering: Vol. 74, no. 1
• PID: 20.500.12556/RUL-175194
• UDC: 620.9:502
• ISSN on article: 1849-0751
• COBISS.SI-ID: 254015235
• Publication date in RUL: 21.10.2025

Record is a part of a journal

• Title: Energija
• Shortened title: Energija
• Publisher: Hrvatska elektroprivreda
• ISSN: 1849-0751
• COBISS.SI-ID: 21908246

Licences

• License: CC BY-NC 4.0, Creative Commons Attribution-NonCommercial 4.0 International
• Link: http://creativecommons.org/licenses/by-nc/4.0/
• Description: A creative commons license that bans commercial use, but the users don’t have to license their derivative works on the same terms.

Secondary language

• Language: Slovenian
• Keywords: energetski prehod, modeliranje energetskih sistemov, energijski tokovi, analize okoljskih vplivov