Spain narrowly avoided another nationwide power outage on June 17, when the Almaraz I nuclear power plant unexpectedly shut down. Just seven weeks after the severe blackout on April 28, this incident revealed the growing fragility of the Spanish power grid. The sudden shutdown at 7:50 PM, triggered by a protective relay on the main generator, could have had far-reaching consequences.
Rapid Intervention by Red Eléctrica Prevents Catastrophe
Thanks to the swift intervention of Red Eléctrica, a massive power outage was averted. Gas-fired power plants were rapidly brought online to fill the 1,100 MW gap. These flexible plants are currently the only support for the grid when “green” energies fail due to weather conditions or nuclear power plants like Almaraz unexpectedly go offline. Marta Castro, regulatory director at Aelec, confirmed that the situation was only managed due to the availability of sufficient synchronous capacities. Without this reliable backup capability, any major outage of a generation plant would result in an immediate power failure.
Increasing System Instability and Political Decisions
The vulnerability of the Spanish energy system has been increasing for some time. The National Commission for Markets and Competition (CNMC) is investigating repeated problems with voltage regulation, which are increasingly exceeding permissible limits. Safety measures, such as reactances and line disconnections, are already operating at their limits, even forcing the connection of additional generation units to ensure stability.
The raw numbers highlight the alarming trend: Shutdowns due to overvoltages have almost quintupled since 2021, from 30 to 140 in just two years. Outages in Almaraz are also becoming more frequent; already in January, the second reactor had to be disconnected due to voltage problems.
In parallel, the government is pushing its ideological plan to close nuclear power plants. This eliminates the only reliable and weather-independent energy source that can stabilize the system. Fernando Sánchez, mayor of Belvís de Monroy and chairman of the “Yes to Almaraz” platform, has called on the European Parliament to investigate the planned closure of the power plant. Brussels is currently keeping the petition open, but the uncertainty remains.
Every unforeseen shutdown, like the one on June 17, reveals the extreme vulnerability of an electrical system that is running out of reserves. Spain is heading down a dangerous path where energy supply increasingly depends on weather conditions, imports, and short-term patches to keep the lights on.
