CLEAN TECHNOLOGIES, vol.7, no.4, pp.84, 2025 (ESCI, Scopus)
This study presents a comprehensive assessment of the energy systems in
eight Eastern European countries—Bulgaria, Croatia, the Czech Republic,
Hungary, Poland, Romania, Slovakia, and Slovenia—focusing on their
energy transition, security of supply, decarbonisation, and energy
efficiency. Using principal component analysis (PCA) and clustering
techniques, we identify three different energy profiles: countries
dependent on fossil fuels (e.g., Poland, Bulgaria), countries with a
balanced mix of nuclear and fossil fuels (e.g., the Czech Republic,
Slovakia, Hungary), and countries focusing mainly on renewables (e.g.,
Slovenia, Croatia). The sectoral analysis shows that industry and
transport are the main drivers of energy consumption and CO2
emissions, and the challenges and policy priorities of decarbonisation
are determined. Regression modelling shows that dependence on fossil
fuels strongly influences the use of renewable energy and electricity
consumption patterns, while national differences in per capita
electricity consumption are influenced by socio-economic and political
factors that go beyond the energy structure. The Decarbonisation Level
Index (DLI) indicator shows that Bulgaria and the Czech Republic achieve
a high degree of self-sufficiency in domestic energy, while Hungary and
Slovakia are the most dependent on imports. A typology based on energy
intensity and import dependency categorises Romania as resilient,
several countries as balanced, and Hungary, Slovakia, and Croatia as
vulnerable. The projected investments up to 2030 indicate an annual
increase in clean energy production of around 123–138 TWh through the
expansion of nuclear energy, the development of renewable energy, the
phasing out of coal, and the improvement of energy efficiency, which
could reduce CO2 emissions across the region by around
119–143 million tons per year. The policy recommendations emphasise the
accelerated phase-out of coal, supported by just transition measures,
the use of nuclear energy as a stable backbone, the expansion of
renewables and energy storage, and a focus on the electrification of
transport and industry. The study emphasises the significant influence
of European Union (EU) policies—such as the “Clean Energy for All
Europeans” and “Fit for 55” packages—on the design of national
strategies through regulatory frameworks, financing, and market
mechanisms. This analysis provides important insights into the
heterogeneity of Eastern European energy systems and supports the design
of customised, coordinated policy measures to achieve a sustainable,
secure, and climate-resilient energy transition in the region.