Poland’s Renewable Energy Transition (2010–2023): A Fuzzy Time Series and Multi-Criteria Assessment of Transition Quality in Electricity Production

This study evaluates the quality and dynamics of the renewable energy transition in Poland’s electricity sector during the years 2010–2023 through an integrated Fuzzy Time Series (FTS) and Fuzzy Multi-Criteria Evaluation (FMCE) methodology. The evaluation is based on five production-related criteria: the production of renewable electricity, the capacity of installed renewable energy sources, investment costs, innovation costs, and total electricity production. Contrary to trend projection and elasticity ratio methods, the new approach determines qualitative transition states (Low, Medium, High) and their transitions over time in the presence of non-linearities and partial progress. The outcome shows a protracted pre-transformational period from 2010 to 2014, with features of perpetual Low → Low transitions and high system inertia. The first qualitatively detectable transition takes place in 2015, where the renewable electricity output regime shifts from Low to Medium, symbolizing the beginning of the moderate transition phase. The Medium regime continues until 2021, with little innovation expenditure, signifying a consolidation rather than acceleration phase. The most significant transition regime shift takes place in 2022, where the system advances from Medium to High, fueled by the cumulative growth of renewable electricity output, capacity, and total electricity production. The High regime is maintained in 2023, indicating a systemic rather than a temporary transition. The results show that the transition of Poland towards renewable energy sources has been following a non-linear and regime-dependent path, with turning points marking observable qualitative state transitions rather than the beginning of trends. The FTS-FMCE approach is a powerful method for separating growth from transformation, and it has been shown to be useful for coal-dependent economies that experience a delayed but accelerating energy transition.