There is a growing focus on the value of interconnections and flexibility as studies shed light on an April blackout that plunged Spain into darkness.
As predicted at the time, the cause of Spain’s blackout was complex, but the means to prevent another might not be tough… and will likely involve increased levels of interconnection and energy storage as part of a package of reforms.
While reports by the Spanish energy regulator and the European transmission system operator (TSO) body ENTSO-E are still in train, Spain’s authorities faced pressure to rush out a detailed account of events after the entire Iberian Peninsula lost power on April 28.
This has so far resulted in a 182-page report from the Spanish government’s National Security Council and a much slimmer study from Red Eléctrica, the national TSO. Both have dispelled initial concerns about an exotic cause, such as a cyberattack, and point instead to an unlikely cascade of events that fatally destabilized the grid.
Simon Gallagher, managing director of UK Networks Services, did a good job of summarising the chain of events in a LinkedIn post:
- The electricity network was operating with high levels of renewable generation, with around 80% of power being inverter based, and faced a shortage of large synchronous generators to control voltage.
- The system experienced unusual oscillations but the protocols that were activated to manage the oscillations caused the voltage to rise and made the system less flexible.
- For reasons that are still unclear, generation plants began disconnecting from the grid even while the voltage was still with grid code limits.
- With grid voltage approaching perilous levels, there were further disconnections, limiting the grid’s ability to recover. Also, it appears some generators were behaving abnormally, for example by not absorbing required levels of reactive power or even injecting it into the grid, precipitating the blackout.
Batteries might have helped avert the blackout
The detail of who is ultimately to blame for the sequence of events is hard to say and is likely to result in lengthy court proceedings, given that the regulator has threatened fines of up to €60 million. For now, however, it is clear the grid technologies Spain needs are in short supply.
Several analyses have pointed out that flexible assets such as grid-connected batteries could have helped avert the blackout, but mainland Spain only has 23 MW of battery storage capacity, according to Red Eléctrica data cited by the analyst firm AleaSoft Energy Forecasting.
Another point to emerge from this episode is that Spain’s regulation needs updating. At the time of the blackout, there was plenty of renewable capacity on the grid that could in theory have helped deliver frequency response and reactive power services to stabilize the network.
But it was not allowed to, with plans to update regulation having languished for years.
Notwithstanding the fact that grid supplies were restored in a relatively short span of time, highlighting the Iberian Peninsula’s black start capabilities, the Spanish authorities are now rushing to address these issues, with potentially positive implications for grid technologies including energy storage.
In June, the government approved electricity market reforms that included a halving of the time taken for the General State Administration to approve new storage projects, addressing a major bugbear for battery plant developers.
The reforms also allow independent energy aggregators to provide grid services, while simplifying the approval of new renewables projects.
“The Spanish electricity system had all it needed to work correctly on April 28, but we have carried out analysis work that allows us to advance measures that will protect us better,” said Sara Aagesen Muñoz, Spain’s Third Deputy Prime Minister and Minister for the Ecological Transition.
These measures come on top of an already brightening outlook for battery projects in Spain. Energy storage is increasingly seen as important to the continued growth of Spain’s massive solar sector, which currently faces stagnation due to price cannibalisation.
Because of this, the Spanish Institute for the Diversification and Saving of Energy this year launched a €700 million co-financing offer for energy storage projects, ending mid-July.
“The aim of the call is to promote the deployment of storage systems that enhance the flexibility of the electricity system, facilitate the integration of more renewable energy and improve security of supply,” said AleaSoft.
“Between 80 and 120 projects are expected to be co‑financed, with a total estimated capacity of between 2.5 and 3.5 GW.”
Hard to see how Spain can go without a battery boost
AleaSoft added that the financing was equal to all the previous funding that the Spanish government had put towards storage-related schemes, through measures such as a €157 million call supporting 45 standalone and thermal storage plants and a €150 million package for 36 hybrid renewables-and-storage projects.
Such initiatives, along with a clear business case for co-locating storage with solar, are attracting growing interest from developers. In June, AleaSoft said Spain had 12.8 GW-worth of under-development battery projects with access and connection permits, a 556-fold increase on the current installed capacity.
Applications for another 17.1 GW of capacity are being processed, AleaSoft said, and Spain’s National Energy and Climate Plan calls for a minimum of 9.4 GW to be installed by 2030. Despite this, funding remains a challenge for project developers.
Panellists at a recent AleaSoft event reported that banks have yet to finance a single standalone or hybrid battery project in Spain, “although interest is high and the financial sector remains attentive,” the analyst firm said.
This finance will have to be unlocked soon, because it is hard to see how the country can go much longer without a boost from flexible grid asset such as batteries.
Publish date: 27 June, 2025