Romania significantly increased its variable renewable generation in Week 34 compared with Week 30, but the stronger renewable output did not translate into lower wholesale electricity prices. Instead, weaker hydropower availability and a sharp increase in thermal generation kept the Romanian market among the most expensive in Southeast Europe.
Romanian variable renewable generation increased by 37.8% compared with Week 30, representing one of the strongest increases among the monitored markets. In isolation, such growth could be expected to ease pressure on wholesale prices by increasing available low-marginal-cost supply.
However, other parts of Romania’s generation mix moved in the opposite direction. Hydropower output declined by 22.66%, while thermal generation increased by 45.86%. At the same time, net electricity imports fell by 55.63%, indicating that domestic generation was covering a significantly larger share of the country’s electricity requirements.
The combination contributed to continued price pressure. Romania’s day-ahead electricity price averaged €152.54/MWh in Week 34, up 6.6% from Week 33. Market conditions remained tight beyond the reporting period, with Romania’s day-ahead price reaching €186.50/MWh on 26 August, the highest daily figure cited among the monitored Southeast European markets.
Romania’s experience highlights why total renewable generation alone is not sufficient to explain wholesale electricity prices. Wind and solar output can increase while the loss of flexible hydropower leaves the system more dependent on thermal generation during the hours when renewable availability is insufficient.
The timing of generation is particularly important. Solar output can significantly increase electricity supply during daylight hours, but its system value is lower when the market is already well supplied around midday. Hydropower, by contrast, can provide flexible generation during evening peaks and other periods when renewable output declines.
The same principle applies to cross-border electricity trade. Romania’s sharp reduction in net imports improved the share of demand covered by domestic generation, but it also meant that more of the system’s requirements had to be met internally, including through higher-cost thermal capacity when renewable and hydro resources were insufficient.
This creates an important distinction between renewable growth and effective system flexibility. Increasing installed renewable capacity can improve overall energy availability, but it does not necessarily eliminate price volatility if generation is concentrated in hours when supply is already abundant.
Week 34 therefore provides a clear warning against treating rising renewable output as an automatic signal of lower wholesale prices. Generation volume matters, but so do timing, flexibility, hydropower availability, cross-border flows and the cost of the marginal thermal unit.
For Romania, the combination of stronger variable renewables and weaker hydro availability demonstrated how quickly these factors can offset each other. The result was a market in which renewable production increased substantially, yet wholesale electricity prices remained elevated because the system still required more expensive and less flexible sources of generation during critical hours.
