Spain Slows Nuclear Phase-out Amidst Energy Turbulence

In a significant policy twist, on 14 August Spain’s government decreed a 3-year extension for a pair of nuclear power plants with combined capacity of about 2 GW. In 2019, the plants at Almaraz, 200 kilometers southwest of Madrid, had been scheduled to shut down in 2027. A phase-out of nuclear power was a major plank of Spain’s coalition government, so the delay has set off a conflict with one of the coalition parties.

The decree blames the extension on “the crisis in the Middle East,” but the decision comes as multiple factors have slowed or reversed several European countries’ policies aimed at phasing out nuclear power. “The Ukraine war, the Iberian blackout, and rising natural gas prices have changed things a lot,” says energy economist Diego Rodríguez Rodríguez of the Complutense University in Madrid, and who is also a former board member of the Spanish National Markets and Competition Commission.

“The government could see that the system was going to need a lot of battery storage to catch up to its booming solar photovoltaic capacity, and they have used the Strait of Hormuz thing as cover.”

Europe’s Nuclear Power Policy Shift

Even before Russia’s 2022 invasion of Ukraine, some European Union countries were reconsidering plans to shut down nuclear power plants or even considering how to add nuclear generating capacity. The invasion raised household electricity prices as EU nations scrambled for alternatives to Russian natural gas. In 2023, Sweden added nuclear to its energy-mix target alongside renewables. In 2025, Belgium voted to repeal its 2003 nuclear-phaseout. In 2026, France cancelled plans to shut down more than a dozen reactors, called for new reactors, and raised its targets for nuclear’s role in the national energy mix. Poland is planning to build its first nuclear power plants in 2028.

Spain’s nuclear capacity has hovered at around 20 percent of the national electricity mix since a 2019 phase-out agreement. Nuclear power has contributed a relatively price-stable alternative to natural gas, and has also provided reliable base load to a grid that incorporates a growing share of time-variable renewable energy sources.

Spain’s long-stated goal has been to use renewables such as wind and solar to replace its most carbon-intensive energy sources; to get there, the government has provided a mixture of incentives. Since 2022, Spain has added more than 20 GW of photovoltaic capacity. As of 2024, wind was contributing about 23 percent and solar 17 percent of the country’s electricity mix.

All of that added renewable energy has created significant technological challenges. Grid operators must balance reactive power (essentially stored power that is shifted back and forth through the grid) with active power (the power drawn by users) to maintain a steady electricity supply. Outdated grid management rules exempted solar power plants from the same reactive power control contributions required of legacy plants, potentially exposing the grid to instability.

On 28 April 2025, a series of power oscillations, voltage gaps, and reactive power control failures set off a cascade of disconnections across the Iberian Peninsula. The resulting blackout affected more than 60 million people for about 12 hours. While Spain’s political parties debated how much of the blame belonged to the grid operator or renewables or other factors, the coalition government, with its tiny majority, could not afford another similar hit to the grid. Nuclear power offered a way to increase stability while the country shored up the resilience of its electric grid.

The Almaraz power plant is in Navalmoral de la Mata, in western Spain. Carlos Criado/Europa Press/Getty Images

Spain Buys Time for a Grid Makeover

For now, Spain’s grid lacks sufficient storage and transmission capacity to absorb new PV as quickly as it is being added. Instead, many installers are going behind the meter, building almost one fifth of the country’s solar PV at industrial sites that can use it themselves, such as at data centers.

But upgrades are coming. In July 2025 Spain’s Ministry for Ecological Transition and Demographic Challenge (MITECO) announced EUR 750 million (US $ 874 million) investment in 65 new resilience measures, including synchronous condensers, flexible AC transmission systems, substation improvements, and switching relays. The country is also adding three more interconnections to France to meet European recommendations.

Investment in energy storage is also booming: At the time of the blackout, Spain had only 28 MW in battery storage capacity, but that number almost sextupled to 193 MW by April 2026. Spain is funding 2.2 GW in near-term large-scale energy storage projects and has a national target of 22.5 GW (including pumped hydrogen and other non-battery systems) by the time of the rescheduled shutdown of its Almaraz nuclear plants in 2030.

Slowing down the nuclear shutdowns buys Spain’s embattled electric grid affordable base power with stable voltage, and avoids using more price-volatile, expensive natural gas. The Almaraz extension raises the question of which other nuclear plant shutdowns the government might delay, given that several were scheduled to end operations around 2030 as well. “The national consortium for dismantling the plants wouldn’t even be able to dismantle them all at once anyway,” Rodríguez says.

Critics of Spain’s energy-policy pivot have argued that extending nuclear power will unfairly cut into the profits of investors in solar, who will have to curtail their power generation more at peak times. Natalia Fabra, an energy economist at CEMFI in Madrid, Spain, wrote this spring in the Journal of the Spanish Economic Association that “keeping nuclear plants online longer may lower prices and emissions at first, but it can also dampen clean investment incentives and lead to higher prices and emissions later on.”

There is no serious talk of building more nuclear power in Spain, Rodríguez says. He regards the delay more as a realistic move to better amortize the seven existing Spanish nuclear plants while the country invests more in storage and grid resilience. The 14 August decree itself insists that “the requested extension does not compromise the contribution of Spain to the renewables objective.”