MADRID, June 13 (Reuters) - Energy companies Iberdrola (IBE.MC) , opens new tab and Endesa (ELE.MC) , opens new tab have proposed a review of Spain's nuclear phase-out calendar, an Energy Ministry spokesperson said on Friday, after a major outage in April reignited debate over nuclear power.

Spain has a plan to close all of its nuclear reactors by 2035 and some were offline on April 28, when the blackout took out power and telecommunications across the Iberian Peninsula. The causes of the outage are still being investigated.

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The proposal was not endorsed by all the companies with stakes in Spain's nuclear fleet. Naturgy (NTGY.MC) , opens new tab and EDP (EDP.LS) , opens new tab did not sign it, the spokesperson told Reuters.

The proposal ties the extension to a revision of the fiscal framework for nuclear energy - the industry has repeatedly urged policymakers to lower taxes, which they blame for hindering the plants' ability to compete on the market.

As such, it isn't in line with the conditions set by Spanish Prime Minister Pedro Sanchez to open a discussion over the review, namely that it guarantees security of supply, safety and that it doesn't weigh on taxpayers, the spokesperson said.

Under the existing plan, the phase-out will start in 2027 with the closure of the first reactor at the Almaraz plant in western Spain, with the plant's second reactor to shut down the following year.

The energy companies' proposal would extend the lifespan of the Almaraz plant to 2030, the Energy Ministry spokesperson said.

Iberdrola didn't immediately reply to a request for comment while Endesa, controlled by Italian energy giant Enel (ENEI.MI) , opens new tab, declined to comment.

A Naturgy spokesperson declined to comment but pointed to previous statements by Executive Chairman and CEO Francisco Reynes, who supported a review of the calendar and an extension of the operation of the Almaraz reactors.

"We are not aware of any letter," an EDP spokesperson said.

EDP Chief Executive Miguel Stilwell d'Andrade said in an interview in April that, when it comes to nuclear, Spain's climate and energy plan should be followed. The plan includes a phase out by 2035.

https://www.reuters.com/business/energy/iberdrola-endesa-propose-review-spains-nuclear-phase-out-calendar-2025-06-13/