The softening of Southeast European day-ahead electricity prices in Week 24 concealed a more complex underlying generation shift. While renewable output increased and wholesale prices declined across most markets, the system simultaneously experienced a sharp reduction in hydropower generation, which forced thermal plants to take on a larger share of regional balancing.
Regional hydropower production fell by 300.2 GWh, or 7.5%, to 3.70 TWh. Türkiye was the main driver of this decline, with hydro output dropping by 229 GWh, or 8.6%, accounting for more than three-quarters of the total regional reduction. Bulgaria also recorded a significant contraction of 42.9 GWh, or 21.8%, while Greece, Italy, Romania and Serbia posted more moderate decreases.
The thermal response across the region was immediate and substantial. Total thermal generation in Southeast Europe increased by 362.6 GWh, or 8.7%, reaching 4.52 TWh. Coal and lignite output surged by 420.6 GWh, or 24.4%, to 2.14 TWh, while gas-fired generation declined by 58.0 GWh, or 2.4%, to 2.38 TWh, indicating a clear shift in the marginal fuel mix.
This structural change highlights where system flexibility was sourced during the week. The region absorbed both higher demand and lower hydro availability not through gas, but through a strong increase in coal and lignite dispatch. Türkiye added 260.6 GWh of coal-fired generation, Italy increased output by 81.2 GWh, and Serbia contributed an additional 66.0 GWh, while Bulgaria and Romania also recorded gains in thermal production.
Greece diverged from the regional pattern. Its thermal generation fell by 6.3%, despite rising electricity demand, as reductions in lignite and gas-fired output outweighed stronger consumption. Croatia also followed a different trajectory, with hydropower increasing sharply by 43.5%, contrasting with the hydro declines seen in most neighbouring markets.
From a commercial perspective, the week reinforces a key structural insight for the SEE power market: renewables can drive price softness, but system reliability continues to depend heavily on dispatchable thermal capacity when hydro conditions weaken. For industrial consumers, traders, and financial institutions assessing renewable PPAs, this dynamic remains critical, as lower spot prices do not necessarily translate into lower system emissions or reduced balancing risk.