Hydropower acted as an existing flexibility resource in Southeast Europe during Week 23 as regional demand increased and variable renewables weakened. Regional hydro generation rose 10.1% week on week to 3.97 TWh. The increase contributed to moderating price pressure.
Week 23 hydro generation by country
The largest contribution came from Türkiye, where hydro output increased 15.4%, or around 356 GWh, to 2.66 TWh. Croatia recorded a sharper percentage rise, with hydro generation up 73.6%. Serbia saw hydro output increase 30.8%, while Italy raised hydro generation by 7.5%.
These changes coincided with a shift in demand and variable generation patterns. Regional demand was up 8.2%, while variable renewable output fell 8.9%. The combination of higher hydro availability and weaker variable renewables occurred during the same weekly period.
Dispatchability and system control in power markets
Hydro value is linked to timing, dispatchability and system control rather than only energy volumes. Compared with solar, hydro can be scheduled around demand peaks. Compared with wind, it is less exposed to short-term meteorological volatility, though it depends on hydrology and reservoir conditions.
In Week 23 conditions included weaker wind and a visible evening price ramp, which supported flexible hydro’s role in moderating prices. The operational characteristics of hydro allowed output to align with system needs during higher-price hours.
Serbia day-ahead prices and local supply effects
Serbia’s day-ahead market reflected the broader balance of supply and demand during the week. Serbian day-ahead prices fell 5.8% week on week to €99.63/MWh. This occurred even as the wider SEE region recorded stronger demand.
Improved local hydro generation was cited alongside higher thermal output and a modest decline in demand as factors reducing local price pressure. In this setting, hydro availability was described as able to outweigh broader regional bullish signals.
Croatia hydro rebound and evening pricing dynamics
Croatia also saw a strong hydro rebound, with hydro generation rising 73.6%. Prices softened only modestly despite the increase in generation.
The commercial impact in reservoir-based systems depends on dispatch decisions rather than water availability alone. Water value rises when evening prices are high, imports are expensive, and gas-linked generation sets the marginal price.
Pumped storage and flexibility requirements for renewable integration
The week’s outcomes were used to support the case for pumped storage and long-duration flexibility. SEE already has large hydro assets, but further renewable integration was described as requiring more sophisticated water management and pumped-storage investment.
The same context included reservoir optimisation and coordination with solar and wind generation to manage variability across the system . Hydro was characterised as a potential flexibility resource that supports grid stability when operated accordingly .
Implications for valuation of flexible hydro portfolios
The flexibility characteristics of hydro were also linked to investor expectations for a premium on hydro-linked capabilities. Assets that can shift generation into high-price hours, provide reserves, stabilise grids and support renewable integration were described as increasingly valuable.
This was said to affect utility valuations, with companies holding flexible hydro portfolios expected to trade differently from generators exposed only to inflexible baseload or merchant solar output . Week 23 was presented as evidence that SEE’s flexibility transition already has an existing balancing asset in hydro .
