Southeast Europe’s electricity market is developing an increasingly pronounced divide between solar-heavy daytime hours and the evening period, when photovoltaic generation rapidly declines. This shift is increasing the value of hydroelectric plants, battery storage and other flexible sources of capacity capable of delivering electricity when it is needed most.
Wholesale electricity prices rose across most of the region during August 17-23, even as aggregate electricity demand weakened. The trend suggests that the timing and availability of generation are becoming more important in determining market prices than overall consumption alone.
Greece recorded the largest weekly increase, with its day-ahead average rising 41.2% to €144.41/MWh. Bulgaria followed with a 16.9% increase, while prices also rose in Hungary, Romania, Croatia and Serbia. Italy remained the most expensive major market, with an average price of €168.31/MWh.
However, weekly baseload averages conceal a more significant structural development. Across several regional markets, hourly electricity prices approached or exceeded €200/MWh during the evening, while prices fell considerably during solar-rich midday hours. This pattern is becoming increasingly visible in Hungary, Romania, Bulgaria, Greece, Serbia, Croatia and Italy.
Serbia has provided one of the clearest examples of these widening intraday price movements. SEEPEX prices exceeded €400/MWh during some evening peaks in August and occasionally approached €500/MWh, despite significantly cheaper electricity during the daytime when solar generation was strong. SEEPEX Chief Executive Miloš Mladenović has identified these growing price swings as one of the defining characteristics of the summer electricity market.
Croatia is experiencing a similar transformation, although the effect is particularly visible from the demand side. The country’s transmission system reached a record summer load of around 3.4 GW between 20:00 and 21:00 on August 11, when most solar generation had already disappeared. Approximately 600 MW of rooftop solar is increasingly reducing measured grid demand during daylight hours before consumption returns to the transmission system in the evening.
The result is a changing definition of electricity scarcity. For much of the previous decade, regional energy security was primarily discussed in terms of whether countries had sufficient annual generation or baseload capacity. Today, a market with rapidly expanding solar capacity can have abundant and relatively cheap electricity at 13:00 and face a shortage only a few hours later, even without a significant change in total daily consumption.
This development is changing the economics of several technologies. Hydropower plants capable of conserving water and increasing output during high-price evening hours are becoming more valuable than inflexible generation producing the same volume of electricity evenly throughout the day. Battery storage can take advantage of the growing spread by charging when solar output suppresses prices and discharging during the evening ramp. Flexible industrial consumers can also increasingly treat temporary reductions in electricity consumption as a market asset.
Romania has already taken steps in this direction by approving a framework that allows eligible consumers to receive compensation for voluntarily reducing electricity consumption during selected periods.
The changing market structure also has important implications for renewable energy financing. Solar projects exposed to merchant prices increasingly face lower capture prices precisely when their electricity production is highest. Co-located battery storage, hybrid projects and contracts that better reflect hourly market value could therefore become increasingly important for protecting project revenues.
For electricity traders, the most important spread may no longer be simply Serbia versus Hungary or Bulgaria versus Greece. Instead, the growing opportunity increasingly lies in the difference between midday energy and evening flexibility within individual markets.
This trend is likely to become even more pronounced as Southeast Europe continues to add solar capacity faster than it develops battery storage, dispatchable generation and transmission infrastructure. The region may have more installed electricity generation than ever before, but its most valuable commodity is increasingly becoming electricity available at exactly the right hour.
