Tractors have leveled dusty ground in Belinchón, Spain, preparing to install thousands of solar panels powered by mini-motors in scorching 35°C heat. Miguel de la Rosa, an engineer for project owner Zelestra, compares building a solar plant to setting up a countryside factory. This 150MW project, backed by pharmaceutical companies, is part of Spain’s solar boom driven by Prime Minister Pedro Sánchez since 2018, capitalizing on abundant sunshine and strong political support for renewables.
Spain’s solar capacity surged ahead of most European countries, with solar sometimes providing up to 60% of the country’s electricity, significantly cutting gas and coal use and lowering consumer bills. Sánchez calls Spain a “global benchmark” in the green energy transition. Yet this rapid growth has led to oversupply, plunging wholesale electricity prices to zero or below about 10% of the time, and even 33% in May 2025. Solar operators face “curtailment” orders to reduce output without full compensation, hurting profits.
The April 2025 Iberian blackout, which left 58 million people powerless for hours, was not caused by solar energy but exposed Spain’s grid weaknesses. The grid, reliant on many small solar installations rather than a few large fossil fuel plants, struggles with frequency and voltage stability. Spain has heavily invested in renewables but underinvested in grid infrastructure, making it Europe’s stingiest grid investor relative to renewables deployment.
The government’s response includes new “anti-blackout” laws and demands for improved grid control, but political opposition blocked key legislation in July. Grid operator Red Eléctrica must upgrade technology without causing electricity bills to spike, balancing reliability and cost.
Oversupply challenges also dampen new solar investments. Projects that sold for €200,000 per MW two years ago now fetch €28,000–€89,000. Batteries are seen as a solution to store surplus solar power and stabilize prices, but Spain lags behind other countries in battery capacity and regulation. Slow permitting and lack of financial incentives hinder battery deployment.
Electricity demand in Spain remains flat since 2004, despite expectations that electrification of industry and transport would boost consumption. Grid connection bottlenecks force utilities to reject many requests, even from large data centers operated by Amazon, Meta, and Microsoft, which see Spain as a top European location.
Experts argue the problem isn’t that the solar boom was too fast, but that government action to modernize the grid and support infrastructure has been too slow. Officials say oversupply and low prices are temporary “transitional” issues expected to balance out within a few years.
