Ember reported that in 2025 wind and solar generated 30% of EU electricity, overtaking fossil fuels at 29% for the first time. Solar alone supplied 13% of EU electricity and grew by more than 20% year-on-year for the fourth consecutive year. The scale-up is changing how wholesale prices behave across the market.
EU generation milestone and regional exposure
In Southeast Europe, the shift is linked to strong solar irradiation and rising air-conditioning demand. The region also has growing renewable pipelines alongside still-limited storage penetration. Greece, Bulgaria, Romania, Hungary and Serbia are described as facing a new daily price pattern.
The pattern involves low or negative prices during sunny midday hours, followed by higher prices in the evening. This timing is tied to how solar output changes over the day. As solar generation increases around midday, wholesale prices can fall sharply.
Duck curve dynamics and evening scarcity
The “duck curve” description centres on morning ramp-up and a midday peak in solar output. At that point, prices may drop because the system has a high volume of low-marginal-cost electricity. As the sun sets, solar generation declines.
If demand remains high while flexible resources are limited, prices can rise quickly in the evening. ACER identified the lack of flexible resources to replace solar generation in the evening as a key driver of the region’s 2024 summer price spikes. The agency also cited limited cross-border capacity as making it harder for Southeast Europe to import lower-priced electricity during stress periods.
Impact on solar capture prices and cannibalization
The economics of solar generation depend on the price during production hours rather than an annual baseload level. With more solar entering the system, plants increasingly compete during the same hours. That competition can push down what is described as the solar capture price.
The issue is referred to as solar cannibalization, where early output benefits from higher daytime prices while later waves reduce the value of those same hours. SolarPower Europe has warned that negative prices and curtailment are eroding business cases in the EU solar sector. The group reported EU installations of 65.1 GW of new solar PV in 2025, slightly below 65.6 GW installed in 2024, marking the first annual decline since 2016.
Project models under negative-price and curtailment conditions
The commercial implications for Southeast Europe are framed around exposure to merchant pricing when negative-price hours increase. Standalone solar exposed entirely to merchant prices is described as becoming riskier under those conditions. Alternative structures are listed as better positioned.
The options include projects with batteries, flexible offtake arrangements, corporate PPAs, curtailment protection or intraday optimization. Industrial consumers that can shift load into midday hours may also benefit from lower daytime prices. These elements are presented alongside the broader market changes affecting revenue patterns.
Grid constraints, congestion and price separation
A grid dimension is also described, with solar growth potentially occurring faster than transmission reinforcement. When grid capacity is limited, renewable output can become trapped in specific areas. This can lead to local congestion, curtailment and price separation.
The regional context highlights that interconnection and internal grid constraints are already major issues in Southeast Europe. Solar deployment is therefore described as needing to be matched with network investment. This linkage connects price outcomes with where generation can physically flow.
Policy framing around flexibility rather than oversupply
A policy message is outlined regarding how negative prices should be interpreted by policymakers. Negative prices are described not as proof that too much renewable energy has been built but as an indicator that the system lacks enough flexibility to absorb renewable output efficiently.
The stated solution set includes building storage, demand response, grid capacity and more granular market signals. Solar is described as rewriting rules in South East European power markets, with winners tied to understanding when electricity is valuable versus when it is not .
The same framing links value movement from surplus hours to scarcity hours with project performance under changing wholesale conditions . Companies building capacity are not presented as the only determinant; operational timing and market participation are highlighted within the described framework .
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