Summer has arrived with excessive force in Spain . June closed as the hottest month on record, and there are no indications that temperatures will ease anytime soon. The streets are emptied, public parks are deserted, and fans run day and night, striving to maintain some semblance of comfort amid these unbearable days. While life adapts to the heat, another crucial aspect is under stress: Spain’s electrical system .
High Demand. As millions of people seek refuge under air conditioning , the Spanish electrical system begins to show signs of saturation. The extreme heat significantly triggers demand , decreases the efficiency of some renewable energy sources, and causes imbalances in the electricity grid.
As reported by the Iberian energy market operator (OMIE) on July 1, the price of the megawatt-hour peaked at 167 euros at 9:00 PM, an unusual figure for this time of night. This increase coincided with high demand and reduced renewable production at the end of the day, forcing the system to rely on more expensive technologies such as natural gas , according to data from Red Eléctrica España (REE).
More Heat, More Network Pressure. Furthermore, an urban phenomenon exacerbates the stress on the network: the heat island effect . In cities, asphalt, concrete, and a lack of vegetation contribute to heat accumulation, which prevents nighttime cooling. Consequently, energy consumption remains high into the night. Households continue to use fans and air conditioning well into the early hours, exerting additional pressure on the system when renewable sources have already decreased from the mix.
But With More Sun … One might think that if there are more sunny hours, solar energy would be enough to meet the growing demand. Indeed, it does contribute significantly: according to REE data, on July 1, renewables contributed 50.6% of the electricity generated, compared to 49.4% from non-renewable sources. However, this average masks what occurs during critical hours.
From around eight or nine in the evening, photovoltaic generation drops significantly, just when demand remains high and temperatures show little sign of easing. During those hours, combined cycle plants—facilities that burn natural gas —support the grid, with more than 14,000 megawatts generated at various times that very night, as per REE data.
There Is an Added Problem. Solar panels do not always perform as expected. As explained earlier, panels can suffer efficiency losses of between 10% and 25% due to high temperatures, losing up to 0.5% yield for every additional degree. Wind also tends to falter; heat waves are often accompanied by stable atmospheric conditions that lower wind production.
Will There Be Any Blackouts? Discussing widespread blackouts may seem alarmist, but comparisons with other countries, such as the United States , make the potential threat disconcerting. However, Spain’s electrical system has demonstrated a certain degree of resilience. Following the blackout on April 28, adjustment services were put into place to stabilize the network in case of critical system failure. While this alleviates immediate collapse, such mechanisms incur additional costs, especially impacting households on the PVPC rate .
Since that incident, REE has maintained an increased safety margin, operating with active backup plants even when unnecessary. This structural increase helps the overall system function more reliably. However, this blackout revealed the deficiencies within a system that desperately needs enhancements in storage, smart grids, and localized response capabilities to disturbances.
A System Under Stress. This summer not only shatters temperature records; it also tests the limits of the electrical system. The combination of prolonged heat, night peak demands, and a more vulnerable renewable generation network creates a perfect storm that stresses the grid during critical moments.
Renewable sources are vital for both the present and the future, but they are not infallible. Their effectiveness largely depends on weather conditions. As heat waves transition from rare events to the norm, the resilience of the electrical grid must hinge on multiple factors: enhanced infrastructure, improved storage solutions, effective demand management, and, most importantly, preparing urban settings to withstand future challenges without disproportionately impacting vulnerable populations.
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