Model-Based Comparison of Nuclear and Renewable Energy Based Strategies for Slovenia

Abstract

Decarbonizing the primary energy is essential for a more sustainable energy supply, requiring a shift away from fossil fuels. To address the climate crisis, significant changes in energy use and supply are necessary, with a focus on reducing electricity generation based on fossil fuels. In the future, coal and gas plants should serve as strategic reserves, operating only during emergencies or other critical situations. Other technologies must replace the lost capacity and meet growing energy demand. By 2050, Slovenia's energy mix is expected to include onshore wind, solar photovoltaic, hydropower, gas plants, coal plants, and nuclear power with pressurized water reactors. Each has a distinct role, requiring careful integration based on environmental and socio-geographic factors.
At the Faculty of Mechanical Engineering, University of Ljubljana, we have developed a dimensionless model of the energy system that allows for the study of various technologies for electricity supply. Using hourly demand data and boundary conditions like primary energy availability and plant technical characteristics, the model simulates energy flows from nuclear, thermal, solar, wind, and hydropower sources, including pumped-hydro storage.
Although initially developed for educational purposes, the model, when provided with appropriate boundary conditions, enables studies of real-world energy systems. Based on reference scenarios derived from national energy and climate strategies, we will analyze the operation of proposed energy systems. The focus will be on two fundamental scenarios from Slovenia's National Energy and Climate Plan (NEPN): one based exclusively on renewable energy sources. and another based on a combination of nuclear and renewable energy sources. A comprehensive analysis of system performance will be conducted, considering technical, environmental, and socio-economic aspects. The primary evaluation criteria will include system stability, greenhouse gas emissions, EROI indicators, import/export dependency, energy costs, and other environmental indicators, such as spatial and material efficiency of the system.