Has Spain's grid operator massively ramped up nuclear and gas, post-blackout?

I thought this was worth writing up once I started to see it get traction across LinkedIn and other social media. A few days ago, Bloomberg columnist Javier Blas posted on Elon Musk's website stating that Spain's grid operator said the grid was running in "strengthened" mode since the April 28th blackout. He points out it's not clear what that means, but he says this coincides with "far more" nuclear power and gas-fired power generation in the mix:

Norwegian nuclear-focused academic Jonas Kristiansen Nøland backed that up, claiming that

"For now, however, maintaining grid stability and ensuring reliability clearly takes priority: more spinning turbines, less immediate reliance on solar and wind, until operators are confident the grid can handle operating at a smaller stability margin safely".

I hope you can clearly see the infographic in the embed above: pay attention to its message, because it'll be important further down. Wind and solar "are now being modestly curtailed". Nøland takes two time snapshots and compares them, to back this up.

The claim also features in an article on far-right climate denial website Breitbart:

As always, the reactions from Blas' audience on X are telling, in that they say out loud what Blas only (literally) winks at:

I decided to look into this a bit further. Spoiler alert: it's of an exaggeration to claim that Spain has shifted fundamentally away from wind and solar. There are elements of truth to some of the claims, but those elements get flipped into hopelessly unjustifiable narratives, as we see above.

Let's dig in. I hope you're prepared for too many charts.

Spain's post-blackout grid

Unless I say otherwise, every bit of data below is sourced from the ENTSO-E transparency platform, which you can access here (it's bloody great). On some of the charts I've included a red line to indicate the date or time of the blackout, where it isn't clear from the generation data. As always, a huge caveat with ENTSO-E data is that they include solar thermal generation among 'solar' - but the vast majority of capacity and generation is utility-scale solar and some residential PV.

First - here's a quick view of generation by fuel type in Spain in the months leading up to the blackout, and the two weeks after:

We can already see that:

• Gas-fired power generation did increase by a noticeable amount, post-blackout - though not higher than previous highs. It's currently roughly at Feb 2025 levels.

• Nuclear power generation is still generating at significantly below its installed capacity (Nøland's LinkedIn graphic makes nuclear look like nuclear's proportion rose massively because it compares to single points in time, but doesn't show the longer-term trend)

• This means that while gas-fired generation increase, the total amount of coal, gas and hydro each day isn't abnormally higher than usual

• The proportion of wind and solar each day show no discernable differences to the patterns of the many weeks prior, in terms of daily generation averages

The main reason it seems like the share of VRE (variable renewable energy, wind and solar) looks like it's 'falling' post-blackout is due to a natural lull in wind speeds across Spain, somewhat offset by the solar proportion rising at the same time (there's a chance solar really was constrained in the few days post-blackout):

You can also get a good idea how Spain has returned to a largely unremarkable state of generation mix by comparing the month of May 2025 to the two previous years - something which accommodates for seasonal shifts but is also recent enough to consider Spain's rapid growth of renewable energy. First, solar and wind:

While wind is experiencing a lull - as often happens - solar has returned to serving a higher proportion of grid power than it did in 2023 and 2024.

It's worth noting here that we can't say 'wind and solar are not being curtailed', or how heavily, without the 'potential' generation of both. That is, according to available sun or wind, how much would the installed generators produce without any limits? As far as I can tell, that isn't publicly accessible data.

What I can say with confidence from the data above is that there is nothing to indicate a noticeably abnormally constrained level of daily average solar and wind generation proportion in Spain.

As Xiao Wang genuinely helpfully pointed out on Bluesky, considering solar's rising installed capacity, shouldn't it be generating more than 2023-2024 - and therefore maybe it really is being heavily constrained?

Without know the solar resource (clouds etc), we can't know for sure, but as it happens, Ember just released a new monthly dataset of monthly installed capacity and it shows solar power grew from 56 gigawatts in May 2023 to 69 in May 2024, and 81 gigawatts in February 2025.

But neither the absolute generation from solar nor the percentage of total jumps massively from 2023 to 2024, as it doesn't from 2023 to 2025 - suggesting to me that there are inherent, longer-term limitations on solar output in May in Spain. It's a fair question but not a slam dunk either way - worth investigating further (maybe when I have the time).

What changes have actually occurred?

What I've shown above are daily averages - that is, if you add up all the solar and wind each day, and then divide it by everything generated that day. The broad picture of dispatch on Spain's grid doesn't seem to have shifted massively - certainly not in a way that indicates the country is tightening the screws on wind and solar to any significant degree.

But when you start looking at daily minima and maxima, you can actually detect some more subtle shifts. Starting with gas:

Gas has the starkest change from pre-blackout. The 'floor' of gas-fired power generation has clearly been lifted quite substantially - now higher than what the average gas generation was before the blackout.

Nuclear destroys the narrative. What looks like a huge rise in nuclear in Spain post-blackout is actually still much lower than the country's fleet usually produces - compare generation now to the start of April:

As I wrote here, more than half of Spain's nuclear power capacity was offline at the time of the blackout - something that has never happened at least in the past ten years. The private companies operating the country's nuclear power stations have argued their profits haven't been high enough (and the taxes on their waste products too high) for them to make enough money to make it worth generating (a line they've taken since well before the rise of renewables).

On a related note: imagine the headlines if 50% of solar had unable to generate on the day of the blackout because their operators deemed it not profitable enough. Strange how the same situation for nuclear doesn't lift a single eyebrow.

Far from the grid operator commanding nuclear to return to full strength, it seems like Spain's nuclear plants have simply reverted to generating at well below full capacity. It's not clear which nuclear power stations are operational, and why, so we have to wait and see.

Solar is also interesting. I've depicted each day's solar generation below, and there is a noticeable reduction in maximum generation compared to the prior week, suggesting the possibility of curtailment - but interestingly not down to levels that are abnormal for this time period.

It's not impossible solar is being constrained, but if it had a 'hard limit' on its maximum output, you'd expect a flat cap effect on each day's profile. It is also possible that solar has an 'indirect' limit, eg it can't be dispatched due to enforced high gas-fired power generation. Maybe less of a solar maximum, and more of a gas minimum?

What does this mean?

After the 2016 blackout in South Australia, the grid operator changed the operation of the grid quite substantially. Australian Energy Market Operator (AEMO) began issuing 'directions to the grid operator to maintain levels of gas-fired power generation in the state. Christiaan Zuur writes nicely about this, here:

The decision to increase grid security based on reliance on fossil fuels caused a very noticeable increase in South Australia's greenhouse gas emissions. In essence, fixing one problem by badly worsening another. Thankfully, the state's decision makers realised that sacrificing human health and environmental stability for a conservative stance on grid security is not sustainable. Soon, the state began installed rotating masses that serve the same function without the emissions.

As Christiaan Zuur wrote for Renew Economy : "The four synchronous condensers in SA allowed AEMO to begin relaxing its dependence on gas generators. We are already seeing more syncons coming online across the NEM, with NSW leading the way on Project Energy Connect and its general system strength needs". SA's gas-fired power generation has been falling ever since:

We're only a couple of weeks away from Spain's blackout. It is far too soon to make any conclusions about how the country shifts in its energy mix over time. But if previous blackouts are anything to go by, any rise in reliance on fossil fuels will hopefully be temporary, as non-planet-heating alternatives are found.

Nuclear power in Spain is certainly not getting the scrutiny I would argue it deserves. Despite being put forward as something the Spanish grid operator has boosted and increased to help grid security, it's still operating at well below 'normal' levels and it's not clear why. It continues to blow me away how much the focus lies solely on wind and solar, with zero desire to interrogate the private companies running other generation types in Spain.

It's also clear that Spain's grid operator has a problematic hesitation around disclosing information. It is really tough to find clear information here, beyond the translations of a speech done by columnists. That void definitely helps the critics of climate policy and renewables, who fill that void with whatever they like. It makes sense to wait a while and perform a careful report, but there is also obviously a few information points they already know, but are choosing not to disclose. It doesn't matter whether that information makes the government look good or bad - it should have been disclosed for transparency's sake.

I can predict we're going to see more stuff like this: small changes blown out of proportion, as a wider effort to cast blame on wind and solar for blackouts, and to cast them as incompatible with modern grids. Your first demand, when you see this, should be pretty simple: show your working.