In August, Southeast Europe’s electricity market shifted as expanding solar generation pushed daytime prices lower while evening supply tightened and drove prices higher. The pattern was reflected in Serbia’s trading outcomes on SEEPEX. Average SEEPEX baseload prices rose 24.9% month on month to €136.70/MWh in August. Traded day-ahead volume increased 8.9% to 547,190 MWh.
The monthly average did not capture the extent of the intraday divide between daylight and evening hours. Electricity at hour 12 averaged €66.11/MWh, while hour 13 averaged €67.06/MWh. Prices then increased as solar output declined. By hour 19, the average reached €210.97/MWh, rising further to €243.65/MWh at hour 20 and €240.25/MWh at hour 21.
The hour-20 level was close to 3.7 times the price recorded around noon, based on the hour-12 average. On individual days, the evening gap widened further. On August 3, SEEPEX prices for hours 20 and 21 reached €553.04/MWh and €550.01/MWh, respectively. The following day, prices stayed elevated at €496.80/MWh for hour 20 and €475.01/MWh for hour 21.
Daytime oversupply and evening scarcity during solar decline
The pricing profile points to a broader change in market structure rather than a single period of high summer costs. Solar capacity growth increases electricity supply during the middle of the day, which places downward pressure on prices when photovoltaic generation is strongest. As additional solar capacity enters the system, the marginal value of an extra MWh produced during those hours declines.
Demand remained relatively strong after solar output began to fall, increasing reliance on other flexible generation sources for the evening transition. Hydropower would typically help manage part of this shift, but weak hydrological conditions reduced hydro availability across the Balkans during August. Nuclear generation also faced operational restrictions linked to high river temperatures and low water levels.
This combination concentrated a scarcity premium into a limited number of evening hours, producing sharper price differences within the same trading day. The resulting hourly pattern also affected how renewable projects perform commercially.
Implications for solar project revenue signals
For solar developers, headline annual generation became a less reliable indicator of commercial outcomes under the new hourly pricing shape. A larger share of solar output is produced during periods when electricity prices are relatively low, increasing the importance of capture price versus a monthly baseload benchmark.
The shift is expected to feed into decisions on plant configuration, battery storage deployment, PPA structures and financing assumptions . Solar remains among the fastest-growing generation technologies in Southeast Europe, but August showed that commercial value depends not only on how much electricity a plant produces, but also on when it reaches the market.
Southeast Europe is gradually moving away from a market defined mainly by annual energy balances toward one where hourly generation and demand profiles increasingly determine project revenues and investment returns .
