Lessons from Spain
Last month's Spain/Portugal power cut has shone a powerful light (ha ha) on grid resilience. TLDR: Renewables were not to blame - but how they were integrated into the grid might have been, in part.
The Spain/Portugal power cut
If excess reliance on variable wind and solar power was going to cause problems in any major economy it was going to be Spain.
Renewables generated an impressive 57% of Spain’s power in 2024, up from 40% in 2014 and just 18% in 2004. However, those figures do not capture the levels reached on the sunniest, windiest days. At the time of the power cut, solar was meeting approximately 59% of Spain's electricity supply, with wind at around 12% - a total of 71% variable renewables. Nuclear power was providing 11% and natural gas 5%.
Just two weeks before the power cut, Spain’s grid operator reported that on 16 April renewable energy had met 100% of electricity demand across the country’s mainland power grid. Wind had delievered 46%, solar 27%, hydroelectric 23% of the mix. Solar thermal, waste and other renewables had made up the remaining 4%. For first time on a weekday, variable sources wind and solar had combined to generate over 100% of total demand. A few days later, solar reached a new record for instantaneous power, meeting nearly 79% of demand.
Fans of renewables were quick to celebrate. And then, on April 28th, Spain went dark.
So it’s a simple story, right? Country embraces renewables; renewables dominate grid; grid fails; failure is renewables’ fault.
Woah, tiger, not so fast!
While we have lots of information, the multiple reports on what went wrong and what to do about it, by the Spanish and Portuguese grids and the the European grid operators’ organisation ENTSOE will take months to assemble.
What information we have suggests that the underlying causes were complex. While there are now millions more armchair experts on grid inertia than last week, the causes are likely to include lack of understanding of grid failure modes, failure to procure a range of grid stability services, some bad decisions about when resources should trip and a lack of connection capacity between Spain and France. The European power grid is one of the most complex machines ever built. It’s a network of networks of networks. It generates harmonics and artifacts that no one fully understands - a search on Google Scholar for European Power Grid Harmonics yields 116,000 results.
While renewables are almost always blamed in the aftermath of major power cuts or grid disruption - and the way they have been integrated into the grid has certainly been found to compound problems - the simple failure of wind or solar power to show up has never yet been found to be the primary cause.
Quick to blame renewables, slow to repent
The context here is that there is a long history of pundits and politicians blaming renewable energy for grid disruption and power cuts, only to be proven wrong.
Here are a few examples (thanks ChatGPT!)
July 2012 - India (world’s biggest power cut)
Claim: Later renewables critics pointed to this as an example of grid instability caused by non-traditional sources.
Reality: The blackout was due to overdrawing by states, poor grid management, and lack of infrastructure—not renewable energy.
September 2016 - South Australia power cut
Claim: Critics blamed high wind energy penetration for the state’s total blackout.
Reality: The root cause was severe storms that damaged transmission towers. A software issue in wind farms triggered a protective shutdown, but it was not the root cause.
2017 - Puerto Rico power issues post Hurricane Maria
Claim: Some argued that investment in solar after the storm would destabilize the grid.
Reality: The original blackout was due to devastated fossil-fuel infrastructure, and renewables helped restoration efforts via microgrids.
January 2019 - Australian power cuts
Claim: Critics pointed to wind and solar causing blackouts in Victoria and South Australia.
Reality: The outages were linked to failing coal units during heatwaves, and load shedding due to demand spikes, not renewables.
August 2020 - California power cuts
Claim: Renewable energy intermittency was blamed for rolling blackouts.
Reality: The main causes were heatwave-driven demand, gas plant outages, and inadequate planning for peak demand, not solar or wind failure.
February 2021 - Texas power cut
Claim: Politicians and media blamed frozen wind turbines for the massive power cut.
Reality: The vast majority of the power loss came from natural gas and coal plant failures due to frozen equipment and lack of winterization. Wind performed close to expected levels.
June 2021 - ERCOT near miss
Claim: Wind power was said to be unreliable during a heatwave.
Reality: The problem stemmed from forced outages at thermal (gas/coal) plants, not renewables.
2021/2022 - UK's Energy price spike
Claim: Some said wind not blowing ("wind drought") caused electricity price spikes and shortages.
Reality: While low wind contributed, the main drivers were natural gas price spikes and outages at aging nuclear and gas plants.
Multiple Years - German power cut fear-mongering
Claim: Some predicted blackouts due to high renewables integration.
Reality: Germany has among the world’s most reliable grids, and no blackouts have been attributed to wind/solar penetration.
I have not found any examples of pundits or politicians admitting they have been wrong to blame renewables. I suspect that they have neither the knowledge of electrical engineering nor any real interest in learning. It’s all part of the political culture wars where everything gets weaponised to push an agenda, score points against opponents or curry favour.
Summary
ENTSOE has issued a chronology of events leading up to and covering the power cut. They have established an expert panel, which will report back in two stages. First a summary of facts, and then a set of recommendations.
It’s going to take up to year to get to the point where all the lessons can be learned. And if past power cuts and grid disruptions are anything to go by, there will be multiple causes and multiple recommendations, covering things like:
The amount of inertia - synthetic or real - that needs to be added to a grid as you enter periods of very high wind and solar output.
The procurement of other stability services like reactive power, short circuit current, etc.
The trip settings for resources on the grid - generators, connections, demand, etc - so that you don’t get multiple GW or tens of GW set to trip at exactly the same moment.
The capacity of connections between France and Spain, and across other European borders.
How to deal with sub-synchronous harmonics across a grid as geographically extended as Europe’s. Did the synchronisation of the Baltic republics’ grids with Europe (instead of Russia) on 9th February this year have anything to do with it.
How to further accelerate black-start - even though Spain and Portugal did brilliantly (remember Heathrow Airport was out for 24 hours in March after a single substation fire).
Improvements to governance - things like taking warning signs seriously (some weird grid behaviours dating back to 2021 look not to have been taken sufficiently seriously).
Potential cyber vulnerabilities.
So, before you blame the Spanish/Portugal power cut on renewable energy, hold your horses and remember the proverb:
It might be better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt.
Thank you for being a calm voice of reason in the face of so much hysterical, politically motivated nonsense.
As an Australian, I'm glad you mentioned the two local examples - both of which were exactly as you described them.
We're now averaging around 40 per cent clean energy - solar, wind and a decent contribution from Tasmanian hydro - and we're not having any difficulties (except when our ageing coal generators cop out, especially in the increasing heat of summer). We'll struggle to reach the current target of 83 percent renewables by 2030, and we absolutely need to build FCAS and storage ad quickly as we can, but we'll certainly get around 80 percent and there's every reason to hope without too many serious problems.
New incentives for domestic batteries will also help!
This crisis will lead to doing RE better and to more RE, not abandonment of RE. What anti-RE sentiment is based in reasons other than doubt, deny, delay on climate change will have to ally with the deniers to promote their desired moratorium on more RE effectively, but that is an ally that has no real commitment to doing emissions reduction 'better'.
Ironic that I expect electricity generation companies that not too long ago were on the denier side in this to be strong proponents of doing more RE but with added synchronous condensers (as well as transmission upgrades) and smart inverters that will allow RE sources and batteries to provide 'virtual' inertia.
Australia's AEMO (electricity market operator) has suggested retro-fitting gas plants with clutches that can allow the generators to disconnect from the turbines and work like synchronous condensers when not actively producing power. They are not yet entirely confident in virtual machine mode as an alternative to spinning machines but I think we will see that option get better, fast.
Worth keeping in mind that even as little as a decade ago there was not much industry confidence solar and wind would grow enough to matter, big batteries didn't really exist and 'grid forming' inverters unheard of. So not sufficient planning and forethought for the rates of growth we've actually been getting.