Serbia’s electricity market will enter a new phase from 5 May, when negative prices become applicable on SEEPEX for the first time, exposing the domestic power system to a price signal already familiar across European markets: hours in which renewable generation, especially solar, exceeds demand and system flexibility is too limited to absorb the surplus.
The change is not a technical footnote. It is a market signal that Serbia’s energy transition has moved from planning documents into operational reality. SEEPEX recorded 69 hours of zero prices on the day-ahead market in the first quarter of 2026, compared with only 8 hours in the same period last year, according to Miloš Mladenović, SEEPEX executive director. He described the introduction of negative prices as part of Serbia’s alignment with the pan-European market model and a precondition for market coupling.
For renewable investors, EPS, traders, banks and industrial consumers, the message is clear: future project economics can no longer be built only around installed megawatts and average annual prices. Serbia is entering a market where hourly volatility, curtailment exposure, balancing costs, CBAM treatment, battery storage, flexible consumption and long-term PPA structures will determine whether renewable energy projects remain bankable.
Davor Pupavac, director for market analysis and risk management in electricity trading at EPS, warned that negative prices are not a problem in themselves, but a signal that surplus electricity will increasingly appear in specific hours. He pointed to the need for new business models, especially around PPA contracts, fixed prices and the treatment of market deviations. EPS already has signed PPA arrangements, meaning the contractual treatment of negative-price hours will become a real commercial issue rather than a theoretical market clause.
The most sensitive issue is CBAM. SEEPEX has linked the widening spread between Serbian and Hungarian spot prices to market distortion created by the full application of CBAM from 1 January 2026. If Serbia cannot secure a workable solution or exemption for electricity, the investment framework for new renewable projects could become materially harder, particularly for projects relying on cross-border offtake, merchant revenue or EU-linked pricing logic.
The immediate response will be contractual and technical. Developers will need PPAs that clearly allocate negative-price risk between producer, buyer, trader and lender. Banks will increasingly ask for downside scenarios covering zero-price and negative-price hours. Industrial offtakers may gain new leverage if they can shift demand into low-price periods. Battery storage will move from optional add-on to core market infrastructure, especially where solar output creates midday oversupply and evening price recovery.
NALED’s Sustainable Energy Council framed the shift as a step toward a more liberalised and Europeanised electricity market, but also warned that Serbia must prepare faster for system flexibility. The council pointed to battery storage, demand-side management, financial-sector participation and closer public-private coordination as key instruments for stabilising the next phase of the transition.
Serbia’s power market is therefore entering a more sophisticated phase. Negative prices will not stop renewable investment, but they will change its financial architecture. The winning projects will be those built around flexible offtake, storage integration, stronger balancing discipline and contracts that recognise that cheap electricity in surplus hours is not a failure of the transition, but evidence that the system now needs the next layer of market design.
