Spain Defers Its Nuclear Reckoning

Spain has bought itself a few more years from Almaraz, the country's largest nuclear plant. The government has extended the operating licence for both reactors until 8 June 2030 (BOE). Unit I had been due to close in November 2027, with Unit II following in October 2028.

The ecological transition ministry, MITECO, has framed the decision around the instability now built into energy markets: the Middle East conflict, the war in Ukraine, and the memory of gas prices turning electricity bills into a political emergency (MITECO). The trade-off is plain enough. Spain gets cheaper power and less exposure to gas in the short term, but pushes several nuclear closures into the same crowded window around 2030.

Why Almaraz keeps gas bills down

Almaraz matters because it is not a marginal plant. In 2025, it generated 14,752 gigawatt-hours of electricity, about 7% of Spain's total supply and 28.5% of its nuclear output (Infobae/EFE, El Periódico de la Energía).

The saving comes through the way Europe's wholesale power market works. Generators offer electricity hour by hour. The most expensive plant needed to meet demand sets the price paid to all suppliers. When that final plant burns gas, the price carries the cost of gas and carbon permits. A large, steady block of nuclear generation keeps gas plants out of more of those hours, so they set the market price less often.

MITECO's own modelling says keeping Almaraz open until 2030 will cut gas-fired generation by 7% compared with Spain's national energy plan, while reducing renewable output by only 1.4% (MITECO, EFEverde). The ministry has not put a household saving on it. The mechanism, though, is direct: less gas at the margin means less exposure to price shocks of the kind Europe saw in 2022.

The 2030 pile-up

The extension does not cancel Spain's nuclear phase-out. It makes it more compressed. Before this order, the timetable was staggered: Almaraz I in 2027, Almaraz II in 2028, with other reactors to follow later. Now both Almaraz units are set to close around the same time as Ascó I and Cofrentes, with Vandellós II and Trillo due before the fleet-wide 2035 deadline (Euronews, World Nuclear Association).

That changes the practical problem. Spain will not be replacing one reactor at a time. It will be trying to manage four closures close together, while building more replacement capacity and handling more decommissioning work in the same period. Enresa, the waste agency, has described the extra waste from the extension as "insignificant" (BOE). But extra years of operation still alter the waste-fund calculation, and the government has not shown how Enresa would manage several closures landing together.

Belgium gives a useful warning. Extending two reactors there required a €15 billion liability agreement with operator Engie, as well as EU clearance for state support (Reuters). Spain's extension has come with no comparable settlement.

Who gains, who loses

The most immediate winners are the roughly 3,000 direct and indirect workers linked to Almaraz, along with the wider economy around the plant in Extremadura (Infobae/EFE, RTVE). The owners, Iberdrola, Endesa and Naturgy, keep earning from an asset whose capital costs have long since been paid down, though MITECO says it refused the tax cuts the utilities had sought (MITECO, elDiario.es). Gas generators lose hours in the market.

For renewable developers, the cost is less visible but still real. If nuclear closure dates can move once, investors may start pricing in the possibility that they move again. That makes long-term commitments harder in a sector already dependent on grid access, planning certainty and stable auctions (El Confidencial). Greenpeace has put the consumer cost through 2033 at €3.831 billion, though that is an advocacy estimate rather than a finding by a regulator (Público).

Portugal is not a bystander. It shares the MIBEL wholesale electricity market with Spain, so Almaraz can influence Iberian prices. The Portuguese environmental group ZERO has called on its government to respond to the extension (Observador), though no public analysis has put a figure on the bill effect.

Spain's case before 2030 is convincing enough: Almaraz displaces gas, and gas is still the fuel that can make power bills politically dangerous. The difficulty lies at the far end of the bargain. Four reactors are now due to close in a tight period, more replacement capacity will be needed at once, and renewable investors have been shown that nuclear deadlines can move. Spain has bought breathing room. It has not yet shown the plan for what happens when that room runs out.