A comparison across five European core markets shows clear year-on-year deterioration, with capture factors falling materially in most. The share of solar production captured within negative price hours also rose, in some cases sharply. The shift reflects higher installed solar capacity combined with consistently weak shoulder-month demand. Despite broader commodity market volatility linked to the Iran conflict, the data suggests capture factors remained driven primarily by structural oversupply in European power markets rather than by fuel or geopolitical price movements.
France – solar capture collapse accelerates pressure for co-located solar reform
France stands out for the scale and speed of deterioration. Capture factors fell to around 0.10 in April 2026, down from roughly 0.42 a year earlier, a drop of 75 percent. Negative price hours rose to 139 from 90, while demand remained seasonally weak on the back of mild temperatures and holiday periods. Nuclear availability also improved, with generation climbing to around 29 TWh in April 2026 from 27 TWh the previous year. This added low-marginal-cost baseload during solar peak hours, reducing room for additional midday solar output, which itself had risen to 3.4 TWh from 2.8 TWh in 2025. With neighbouring markets facing similar surpluses, export opportunities were limited, leading to deeper domestic price collapses. The share of solar generation produced during negative price events jumped from 29.2 percent to 45.1 percent year-on-year.
Report: solar-led shift could halve EU power system costs
These conditions support France's proposed reform of large-scale solar CfDs. The energy regulator CRE has proposed shifting support from a solar capture-based reference price to a baseload index, while reducing compensation during negative price periods. Under the current structure, the state effectively absorbs much of the cannibalisation risk borne by standalone solar. April 2026 illustrates how rapidly that exposure is rising. The proposed redesign transfers a larger share of the risk back to generators while explicitly favouring co-located PV and BESS. By allowing batteries to charge during negative price periods without losing support, and by extending compensation to energy shifted into higher-priced hours, the reform rewards flexibility rather than pure generation volume.
Germany – longer negative price events expose growing merchant risk for solar
Germany shows a similar but more structurally embedded trend. Capture factors fell from around 0.40 to approximately 0.26 year-on-year, a decline of one third, while negative price hours rose from 75 to 123. The share of solar generation produced during negative price periods climbed from 32.6 percent to 46.8 percent.
A key structural element is the legacy EEG framework. Older renewable assets continue to receive support during negative price periods of up to six consecutive hours, reducing the incentive to curtail generation during oversupply. While newer EEG rounds impose stricter rules, the legacy fleet still accounts for a significant share of installed capacity.
Flexible demand reshapes the power picture
EEX data shows that negative pricing events are becoming not only more frequent but materially longer. In April 2025, Germany recorded 13 events lasting more than one hour, of which only two extended beyond the six-hour threshold (after which many older EEG-supported assets lose subsidy eligibility). By April 2026, events of more than an hour had risen to 22, with eight exceeding six consecutive hours. The longest continuous negative pricing period also jumped, from seven hours to 17. Combined with continued solar additions and limited demand flexibility, this is producing pronounced midday price suppression, particularly during high-irradiation periods in spring.
Italy – regional grid constraints push southern markets toward persistent zero prices
Italy presents a distinct case because of its market design, which does not currently allow negative prices in the day-ahead market. Structural features, including ancillary service mechanisms, effectively maintain a price floor. Instead, oversupply shows up in a rising number of zero-price hours. Capture factors fell from around 0.75 to approximately 0.71 year-on-year, the second-lowest level on record after May 2025. The decline is modest but notable given Italy's still relatively low solar penetration. The effect is highly regionalised: April 2026 saw zero-price hours emerge across central-southern zones, with Calabria and Sicily recording repeated occurrences, whereas April 2025 showed almost none. Northern Italy remained largely unaffected. Southern regions, with higher solar exposure and weaker interconnection, are increasingly facing local oversupply, while limited north-south transmission capacity constrains system balancing.
Spain – winter oversupply signals that solar cannibalisation is no longer seasonal
Spain's data shows that capture risk is no longer confined to spring and summer. Capture factors fell slightly in April, from around 0.30 to 0.28 year-on-year, but the winter dynamic is more striking. In February 2026, capture factors dropped to around 0.18, compared with roughly 0.71 a year earlier, driven largely by exceptionally strong hydro output displacing other generation. Negative price hours surged to 148 in February 2026 from zero the year before. In April, negative pricing rose from 117 to 138 hours, with the share of solar production occurring during negative price periods rising from 35.2 percent to 41.2 percent. Spain's rapidly expanding solar fleet, combined with limited storage and constrained export capacity, is increasingly exposing assets to both seasonal and structural price pressure.
Poland – early signs of solar oversupply emerge in a traditionally thermal market
Poland is also showing visible signs of cannibalisation. Capture factors declined from around 0.54 to approximately 0.40 year-on-year, a drop of roughly 25 percent, while negative price hours rose from 75 to 87. The share of solar output generated during negative price periods edged up from 27.1 percent to 28.5 percent. Although less extreme than in France or Germany, these shifts indicate that solar-driven price pressure is becoming material as renewable penetration rises. Poland's coal-heavy generation mix and lower solar buildout have so far helped maintain higher capture factors than in more saturated Western European markets, but closer integration with neighbours suggests similar pressures could intensify, particularly during low-demand periods.
Widening solar-driven spreads strengthen the investment case for BESS across Europe
Across all markets, both day-ahead and intraday top-bottom (TB) spreads available to BESS widened materially year-on-year. France and Germany recorded some of the sharpest increases, with April day-ahead spreads expanding by roughly 20 percent. Germany in particular saw intraday volatility intensify further. Spain showed a clear widening trend from a lower base, while Poland remained the most volatile market overall, with spreads up around 15 percent year-on-year in April. Italy again displayed strong regional divergence: April day-ahead spreads in the south rose by one third year-on-year, compared with around 20 percent in the north. The broader trend is clear: midday oversupply is driving sharper price swings, raising the value of flexible BESS assets.
Bulgaria’s solar future – challenges, opportunities and the path forward
Taken together, the April 2026 data suggests European solar markets may be entering a phase in which severe midday oversupply is no longer an isolated event but a recurring structural condition, particularly in shoulder months. Early May has reinforced this, with several markets recording record or near-record negative pricing events. In Germany and France in particular, prolonged negative-price periods are becoming common, raising the prospect that 2026 could set new lows for solar capture factors across parts of Europe.
The broader implication is that solar deployment is now advancing faster than system flexibility. Storage pipelines are expanding rapidly, but current BESS penetration remains too limited to compress day-ahead spreads or absorb large-scale midday surpluses at system level. Until BESS deployment, demand-side flexibility and grid expansion scale more meaningfully, markets are likely to continue to see deeper midday price collapses, wider spreads and increasingly volatile capture outcomes during high-generation months. (David Battista/hcn)
