Recent data highlights the critical role of hydroelectric generation in stabilizing power markets across Southeast Europe, particularly during periods of high demand. In January and February 2026, Serbia experienced a remarkable increase in hydro output, surging by 186%, while Greece saw a 155% rise. This spike in production effectively insulated both markets from the volatility typically associated with gas prices.
In Serbia, the abundance of hydro resources enabled the electricity system to accommodate a demand growth exceeding 33% without triggering significant price increases. The reliance on hydro reduced the need for imports during peak consumption hours, resulting in relatively stable prices on the South East European Power Exchange (SEEPEX) compared to neighboring Hungary and Romania. Similarly, Greece benefited from hydro’s ability to displace gas during peak intervals, thereby mitigating exposure to TTF volatility and narrowing price spreads with Italy.
However, the stabilizing effects of hydroelectric generation are not uniform. As noted by analysts, when reservoir levels are high, hydro can serve as an effective flexibility resource that quickly ramps up output and suppresses marginal pricing. Conversely, as reservoir levels decline, this flexibility diminishes abruptly, leading to potential market instability.
The situation in Romania starkly contrasts with the experiences of Serbia and Greece. Weaker hydro conditions during the same timeframe resulted in increased prices in Romania, which rose above €150/MWh. The lack of sufficient hydro flexibility forced Romania to rely more heavily on gas and imports, illustrating the uneven influence of hydro resources across the region.
This structural risk is compounded by market perceptions that often overestimate current hydro conditions. Forward curves and trading behaviors tend to assume that strong hydro months will continue indefinitely, leading to under-hedging and mispricing of risks associated with reversion once flows normalize. Such miscalculations can lead to abrupt repricing within markets when conditions shift.
The interaction between hydro and other energy sources adds another layer of complexity. High levels of hydro output can cause nuclear plants’ inflexibility to exacerbate curtailment issues elsewhere in the energy mix. Conversely, during low hydro periods, balancing renewable intermittency becomes increasingly challenging, further emphasizing gas’s marginal role in meeting demand.
From a systemic perspective, while hydropower provides valuable optionality during surplus conditions, it does not offer reliability as a long-term structural hedge. Climate variability further complicates long-term forecasting efforts related to reservoir management strategies.
In conclusion, while hydroelectric generation serves as a temporary volatility suppressant in Southeast European power markets, it should not be viewed as a dependable structural anchor. Market participants must prepare for swift transitions back to gas-driven pricing once hydrological support wanes; periods of apparent stability during high hydro output may precede significant price adjustments.
