Romania provided the clearest illustration of the distorted daily curve. OPCOM’s day-ahead baseload settled at €129.98/MWh, with traded volume of 39,454.3 MWh. Yet its quoted peak-load strip was only €90.81/MWh, compared with an off-peak product of €169.14/MWh.
Electricity fell to approximately €13.25/MWh during the afternoon solar period before climbing to €200.76/MWh at 22.00. The distance between the low and high exceeded €187/MWh.
This inversion has direct consequences for renewable valuations. A Romanian solar plant may appear exposed to a €130/MWh baseload market, but much of its physical output is delivered during hours clearing at €13–€30/MWh. Revenues based on the arithmetic daily average will therefore overstate merchant cash generation unless the project has a contract for difference, a fixed-price PPA or colocated storage.
The same pattern appeared further west. Hungary declined to €13.52/MWh at 14.00 before reaching €200.88/MWh at 21.00. Slovenia fell to €13.62/MWh during the same central-European hour and peaked at €199.76/MWh in the evening.
Hungary’s intraday range reached €187.36/MWh, while Slovenia’s was €186.14/MWh. A battery buying at the day’s minimum and selling at the maximum would face a theoretical gross spread approaching €187/MWh. At 85 per cent round-trip efficiency, the charging cost of electricity bought at €13.52/MWh rises to only about €15.91/MWh per discharged megawatt-hour, leaving a theoretical energy margin near €185/MWh before degradation, connection charges, trading fees and imbalance exposure.
That maximum spread is available for only a limited period and cannot be extrapolated across every battery cycle. Storage deployment will itself lift afternoon prices and reduce evening scarcity. Even so, the 24 July curve provides a stronger commercial signal than a conventional annual baseload forecast: short-duration flexibility is valuable precisely because aggregate demand can fall while the evening marginal price still approaches €200/MWh.
Bulgaria and Greece showed a flatter profile. Both declined to approximately €72.23/MWh around noon and reached a daily maximum near €162.09/MWh during the morning. Their solar discount was material but much less severe than in Romania, Hungary or Slovenia. Bulgaria’s nuclear baseload, regional interconnection and growing battery fleet reduced the depth of its afternoon trough, while Greece retained greater dependence on gas-fired generation through the day.
