Serbia’s SEEPEX to allow negative power prices from May 2026, reshaping generator economics and financing

Serbia’s electricity market is moving into a new pricing regime after SEEPEX announced that it will allow negative power prices starting in early May 2026. While the regulatory step is framed as technical alignment with European market design, it also rewires how revenues and risks are distributed across generators, traders and lenders—potentially changing investment priorities in the country’s power sector.

Negative pricing timetable and EU-aligned limits

The first day-ahead auction that can clear at negative prices will take place on 5 May 2026 for delivery on 6 May. Intraday trading is scheduled to follow later that evening.

The move replaces Serbia’s existing 0 EUR/MWh floor with –500 EUR/MWh for day-ahead and –9,999 EUR/MWh for intraday trading. The limits are described as consistent with EU harmonised price limits coordinated under ENTSO-E.

Generation: shifting exposure from fixed revenue to two-sided risk

For Serbia’s generation fleet, negative pricing turns electricity output into a two-sided exposure where revenues are no longer capped at zero. The source highlights that thermal assets—especially lignite-fired plants operated by EPS—are structurally most exposed because baseload-oriented units face constraints when ramping down.

Under negative price conditions, operators must choose between keeping output online and absorbing losses during negative price hours or reducing generation at the cost of cycling inefficiencies, higher maintenance costs and possible system constraints. Even a relatively limited number of negative price hours could weigh on earnings for inflexible assets: the article cites an early-stage range of roughly 50 to 150 hours annually, potentially rising toward 200 to 400 hours as regional renewable penetration increases.

Hydropower presents a more mixed picture. Flexible hydro can gain optionality by withholding generation during negative price periods and dispatching during peaks. Run-of-river plants remain partially exposed due to limited storage capacity.

Renewables: lower capture assumptions and less merchant bankability

The introduction of negative pricing also changes the economics assumed in renewable project models. For solar in particular, the article notes that output tends to coincide with oversupply periods, which should compress capture prices—the realised average relative to baseload.

As an example of how this can play out elsewhere in Europe, the source points to Germany where solar capture rates have already fallen to about 70–85% of baseload, with further compression during high-output periods. In Serbia—where utility-scale solar CAPEX is typically cited at €600,000 to €900,000 per MW—the updated financial approach would require more conservative price assumptions and explicit modelling of negative-price exposure.

The article also flags potential structuring responses such as incorporating price floors, collars or hybrid PPA structures. Wind generation is described as somewhat more resilient because its production profile is less directly tied to midday oversupply; however, high-wind events across interconnected markets—particularly Romania and Bulgaria—can still trigger negative pricing episodes. The overall conclusion is that standalone renewables without flexibility are becoming less bankable on a pure merchant basis.

Flexibility assets: batteries, pumped hydro and demand response move toward core investment status

Negative pricing creates an economic signal for flexibility. Battery energy storage systems (BESS) are positioned as central because they can arbitrage between negative and peak periods. With BESS CAPEX cited at €400,000 to €700,000 per MWh, the source argues that revenue stacking becomes more robust in a negative-price environment by combining energy arbitrage with balancing services and capacity or ancillary revenues.

It also references benchmarks from more volatile EU markets where arbitrage spreads of €100–200/MWh have been observed. Pumped hydro storage—particularly projects under development in Serbia—is described as gaining renewed strategic relevance due to its long-duration flexibility for system balancing.

The article adds that industrial demand response could emerge as another monetisable asset class: large consumers such as metals, chemicals and hydrogen producers may be able to turn electricity consumption into a profit centre during negative price periods.

Trading: wider spreads increase opportunity but raise operational and collateral demands

For traders operating on SEEPEX, allowing negative prices expands the opportunity set while increasing complexity. Intraday trading is expected to become significantly more valuable as short-term volatility rises and spreads widen.

The source lists capabilities likely to matter most: high-frequency forecasting of renewable output; real-time optimisation of portfolios; and cross-border arbitrage using available interconnection capacity. It also notes that Serbia’s regional grid position means price formation will increasingly reflect developments in neighbouring systems across Greece and Central Eastern Europe.

At the same time, risk management requirements are expected to increase sharply because negative prices create non-linear downside exposure. That implies enhanced collateral management and more sophisticated hedging strategies.

Banking and financing: repricing risk for merchant exposure while boosting flexibility returns

For lenders and investors, the shift toward negative pricing represents a structural change in underwriting assumptions. Merchant exposure is described as materially riskier than under traditional baseload-focused project finance models built on stable price expectations.

The article suggests financing structures may increasingly require long-term PPAs with price floors or minimum revenue guarantees; hybrid configurations combining generation with storage; and higher equity buffers designed to absorb volatility. Debt sizing is expected to become more conservative—particularly for solar projects—as debt service coverage ratios (DSCR) would need to account for intervals when prices go negative alongside lower capture rates.

In contrast, flexibility assets such as BESS are expected to attract growing interest from infrastructure funds and private equity. The source cites a potential shift in return profiles—from around 8–10% toward roughly 12–18%+ in volatile markets—moving these assets closer to “core” investment territory for some investors.

VAT treatment adds an extra layer of financial friction

The article also highlights a specific structural issue tied to taxation. Under Serbian law described in the source text, negative pricing is treated as a service transaction; domestic entities remain liable for 20% VAT even when selling electricity at a loss. This could create cash-flow pressure and influence trading structures, including whether participants use foreign entities operating under different VAT regimes.

System impact: better integration comes with imported volatility

At system level, allowing negative prices is presented as a prerequisite for full integration with EU market coupling mechanisms. Without it, cross-border flows would be artificially constrained because price signals cannot fully reflect system conditions; removing the floor should enable more efficient transmission capacity allocation aligned with European market clearing algorithms.

The trade-off is increased volatility: as renewable penetration rises across South East Europe, Serbia may see price patterns driven more by regional dynamics than domestic fundamentals alone.

Taken together, SEEPEX’s planned move is not just a rule change but a redefinition of how market behaviour works—making price signals continuous rather than bounded by zero values. For generators facing new downside risk profiles, traders managing wider intraday swings and lenders reassessing merchant assumptions alike, negative pricing marks the beginning of a more complex but potentially more integrated electricity market across Serbia and the wider SEE region.