The energy landscape in South-East Europe is undergoing significant transformation as hydropower, once considered a reliable balancing resource, increasingly reflects the impacts of climate variability. In the first quarter of 2026, hydropower generation has shown a marked decline, emphasizing its evolving role within the region’s energy mix and its implications for market dynamics.
Hydrological conditions across South-East Europe have been inconsistent, mirroring broader European trends characterized by volatile precipitation and fluctuating reservoir levels. In Week 16 of 2026, total hydro generation fell by 3.45% compared to the previous week. Notably, Romania and Bulgaria reported sharp declines of 15.79% and 25.68%, respectively, while Italy and Croatia saw increases of 17.8% and an extraordinary 270%, albeit from a low starting point.
The declining predictability of hydropower output raises concerns about its traditional function as a stabilizing force in the energy system. Historically viewed as a quasi-firm resource, hydropower is now behaving more like a secondary renewable source influenced by short-term weather patterns and long-term climate changes. This shift has significant implications for energy price formation and thermal dispatch strategies across the region.
When hydropower is abundant, it can lead to rapid reductions in market prices as it displaces higher-cost thermal generation. However, during periods of underperformance—especially when coinciding with weak solar or wind conditions—the reliance on more expensive gas or lignite becomes necessary, resulting in heightened market volatility.
The interplay between hydro and wind resources has become critical; several markets faced simultaneous weaknesses in both sectors during Q1 2026, leading to compounded supply deficits that existing flexibility resources could not adequately address. This scenario has triggered substantial price increases even with stable demand levels across parts of South-East Europe.
Looking forward through 2026, hydropower is expected to act more as a swing factor than a stabilizer within the energy system. While improved inflows in late spring and early summer could temporarily alleviate some pressure on thermal generation, ongoing variability is anticipated with hydro output likely fluctuating around historical averages but exhibiting wider deviations.
In scenarios marked by prolonged dry conditions or below-average inflows, hydro deficits may become significant drivers of price spikes during low renewable output periods. Such outcomes would further entrench the role of thermal generation while increasing reliance on cross-border electricity imports.
Thermal Generation: The Evolving Backbone of Energy Systems
As hydropower’s reliability wanes, thermal generation continues to serve as the structural backbone of South-East Europe’s power systems amidst evolving market pressures including renewable growth and carbon pricing mechanisms. During Week 16 of 2026, thermal output remained stable at approximately 4,300 GWh—an increase of 0.18%—though internal shifts were evident: gas-fired generation rose by 3.31%, while coal and lignite output decreased by 3.35%.
This trend indicates that thermal generation is being reallocated across various functions rather than diminishing altogether. Gas-fired plants are increasingly utilized for their flexibility in responding to short-term fluctuations in renewable energy production, particularly evident in markets like Italy and Greece where wind and solar penetration is growing rapidly.
Conversely, coal and lignite remain vital for providing baseload stability in regions such as Serbia where lignite generation saw an increase nearing 20% during Week 16. The diverse thermal archetypes emerging across South-East Europe include gas-led flexibility systems (Italy and Greece), coal/lignite-dominant systems (Serbia), and hybrid systems (Romania and Bulgaria) that combine various sources for balanced energy provision.
As we look ahead to the period from 2026 to 2030, thermal generation will continue to play an essential role but will experience changes in utilization patterns. Gas plants are expected to operate at lower capacity factors while commanding higher marginal values due to their responsiveness in balancing markets amid price spikes.
Nuclear Energy: Stability Amidst Limited Growth Potential
Nuclear power remains a source of low-cost, low-carbon baseload stability within the broader European context during Q1 2026; however, its influence within South-East Europe is limited by existing capacity constraints and slow expansion rates. Improved availability from nuclear facilities in Western Europe has contributed positively to regional system stability through market coupling effects that help stabilize cross-border price fluctuations.
The nuclear capacity in South-East Europe is concentrated primarily within Romania (Cernavodă), Bulgaria (Kozloduy), and Slovenia (Krško). These facilities are crucial for providing baseload electricity while supporting export capabilities; however, their overall contribution remains relatively small compared to hydropower and thermal sources.
Nuclear’s defining characteristic lies in its stability—it operates independently from weather conditions unlike renewables—and is insulated from short-term fuel price volatility seen with gas-fired plants. Nevertheless, nuclear power faces limitations due to its lack of short-term flexibility; long development timelines; substantial capital investment requirements; and regulatory complexities that hinder rapid adaptation to changing market dynamics.
Future developments regarding nuclear energy’s role will heavily depend on policy frameworks and investment strategies within the region. While life extensions for existing plants appear likely—maintaining current capacities—new projects face significant hurdles before they can materially impact regional energy mixes before the early 2030s.
