Global energy analysis provider Aurora Energy Research notes that electricity spills have increased significantly in Spain , in line with its previous analyses.
In the first half of 2026, unpaid electricity injections amounted to 2.5 TWh, which is 50% higher than those recorded in the whole of 2024 and more than triple those of the first half of last year.
Uncompensated electricity curtailment refers to generation that is discarded by the operator and not fed into the grid. In June of this year alone, record electricity curtailment reached 1.2 TWh, almost six times more than in June last year and nine times more than two years ago.
In the last two years, 20 GW of new photovoltaic solar power capacity and 2 GW of wind power have been added to the electricity grid. This has increased the total electricity generation capacity from all technologies by 17% to approximately 150 GW in Spain.
In this context, in June of this year, photovoltaics reached a record 29.5% share of the electricity generation mix, according to data from Red Eléctrica de España. This represents an increase of three and a half percentage points compared to June of last year and seven percentage points compared to the same month two years ago.
The new renewable energy capacity added in the last two years, however, has been primarily located far from consumption points and has led to an increase in localized electricity curtailment. According to Aurora's nodal model, the territorial distribution of curtailment is highly uneven, even within the same province. This year, Badajoz, Zaragoza, and Cáceres are the provinces where Aurora anticipates the greatest curtailment.
Mario Prinetti Polo, Senior Associate at Aurora Energy Research, commented: “The earlier heat waves this year have contributed to very high electricity curtailments in June. Overall, the first half of the year has seen high renewable energy production and high curtailments in Spain, especially in the last two months.”
"The addition of batteries is key to strengthening the flexibility of the electricity grid. So too will be the planned reinforcements to the grid. In this regard, it is very important to address the areas of greatest congestion. Currently, the distribution of electricity surpluses is very uneven across the country, with Extremadura and Aragon being the most affected autonomous communities," he added.