Solar photovoltaic generation reduced Spain’s wholesale electricity costs by an estimated €17.02 billion between January 2025 and June 2026, according to a study by Spanish solar association UNEF. The analysis estimates that average day-ahead market prices would have been 86% higher in a scenario without solar generation.
UNEF compared actual day-ahead prices with modeled prices excluding output from utility-scale solar plants and self-consumption systems. In that scenario, the average price would have reached €112 per megawatt-hour, compared with the recorded €60.2/MWh—a 46% reduction.
Utility-scale solar accounted for an estimated €14.23 billion in savings, while residential and commercial self-consumption contributed €2.79 billion. The total comprised €10.86 billion in 2025 and €6.16 billion in the first half of 2026.
The association says solar lowers prices through the day-ahead market’s marginal pricing mechanism: low-variable-cost generation displaces more expensive sources and reduces the market-clearing price. Self-consumption also cuts demand from the grid, extending the effect beyond households and businesses with rooftop installations. UNEF estimates that each euro invested in solar PV generates €8 in wholesale price savings.
The modeled effect was especially large in June 2026. The average day-ahead price that month was €69.6/MWh; UNEF estimates it would have been €162.7/MWh without solar, a difference of €93.1/MWh.
The study draws on data from electricity market operator OMIE, grid operator Red Eléctrica and UNEF. It models market prices without utility-scale solar and self-consumption while accounting for how other generation technologies could respond to price changes.
The estimated wholesale savings do not equate directly to reductions of the same size in consumers’ electricity bills. The analysis excludes other bill components, including technical constraints, balancing services and forward contracts. UNEF also notes that gas-fired combined-cycle plants and hydropower facilities could respond differently under substantially changed market conditions.
Sources: pv magazine.