The levelised cost of solar electricity has never been lower. The capture rate — the ratio of average solar revenue to average wholesale market price — is declining in every market with meaningful solar penetration, at a pace that most project financial models do not adequately reflect.
Germany recorded a solar capture price of €47/MWh in 2024, representing a capture rate of 59% — the lowest in Europe — despite still-elevated baseload prices. In 2025, Germany's average solar capture rate fell further to approximately 54%, down from 98% in 2022. Capture rates fell below 50% sixty-three times in 2024, rising from thirty-one occurrences in 2023 and eleven in 2022. In Spain, capture rates fell from 0.70 to 0.36 between 2023 and 2024. In Poland, solar capture factors hit approximately 50% in peak summer months of 2025. MinesSolarQuarter
The mechanism is structural rather than cyclical. Solar generation is temporally concentrated in midday hours that are spatially correlated across wide geographic areas. As installed capacity rises, solar increasingly displaces thermal generators as the marginal producer during its generation hours. Once thermal units are fully displaced, prices can fall by €100/MWh or more within the clearing mechanism. The result is that each additional unit of solar capacity generates into progressively lower price environments — the cannibalization effect.
Research on European electricity markets quantifies that a one percentage point increase in domestic solar market penetration is associated with a 1.39 percentage point decline in solar value factor, while cross-border spillovers — reflecting the spatial correlation of solar generation — produce a further 2.38 percentage point decline per percentage point of neighbouring zone solar penetration. The cross-border effect exceeds the domestic effect. Interconnection expansion, the standard policy response to geographic concentration of renewables, does not mitigate solar cannibalization and may accelerate it by more efficiently propagating price-depressing solar imports across bidding zones.
Modelling of the cannibalization effect on investment returns finds that projected profitability can fall from 33% to between 13% and negative 40% depending on assumptions about future variable renewable capacity expansion, with investment thresholds rising by 13–67% once cannibalization dynamics are incorporated.
The engineering mitigations are established in concept but not yet deployed at the scale required. Co-located battery storage shifts solar revenue from saturated midday hours into higher-value evening periods; UK analysis indicates improvements of 15–25 percentage points in effective capture rate at current storage costs. East-west oriented arrays reduce midday generation concentration at a 10–15% output penalty, often producing a net revenue improvement in high-penetration markets. Direct industrial co-location eliminates wholesale market exposure entirely. Hydrogen electrolysis provides a firm midday offtake at near-zero market price, converting surplus solar into storable chemical energy.
For practitioners in emerging solar markets — particularly Sub-Saharan Africa where grid scales are small and storage and interconnection limited — the capture rate trajectory of European markets represents the arrival conditions for high-penetration solar deployment at lower absolute installed capacities. South Africa's Western Cape is already recording REIPPPP curtailment events at midday peak solar periods. The institutional and market structure design decisions made during the current deployment phase will determine whether African solar markets encounter capture rate collapse under crisis conditions or manage the transition through proactive market architecture.
REM Episode 18 is published at donfackfortune.medium.com.
Donfack Fortune is a mechanical engineer and energy systems analyst publishing Renewable Energy Mall & Engineering Review.