Both Sweden and Canada have experienced massive power outages – but for a different reason than Spain.
People in Madrid wait on a platform as metro operations resume following the major power outage in Spain and Portugal on April 29, 2025.(Photo: Violeta Santos Moura / Reuters / NTB)
The power grid was knocked out in Spain and Portugal on April 25. Around 55 million people were affected in what The Guardian calls the worst power outage in modern European history.
People were trapped in lifts, massive traffic chaos spread, trains stopped running, and phone coverage disappeared.
It is still unclear what happened, but it was not a solar storm.
Solar storms have in fact caused major power outages before.
"Illustrate the kind of chaos that arises"
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In southern Sweden, 50,000 electricity customers lost power for an hour in 2003 due to an exceptionally strong geomagnetic storm, according to Lund University.
And there are several examples in modern times.
Here, the sun emits enormous amounts of charged particles. This is a so-called CME, which can create geomagnetic storms on Earth if it hits us.(Photo: NASA)
When Magnar Gullikstad Johnsen saw the news about the power outage in Spain, he reacted quickly.
"I ran to check the data from the sun," he tells sciencenorway.no.
Johnsen leads the Tromsø Geophysical Observatory and works on developing space weather forecasting in Norway.
"But it was very quiet that day," he says.
There was no solar storm raging and knocking out the power grid in Spain and Portugal on that April day in 2025.
Johnsen points to another recent power incident that had major consequences. At the end of March, a transformer exploded at Heathrow Airport. It led to more than 1,000 cancelled flights and hundreds of thousands of stranded passengers, according to Bloomberg.
"These two events illustrate the kind of chaos that arises when society is without electricity, so it can't be emphasised enough how incredibly important that infrastructure is," says Johnsen.
Northern Lights seen in the wilderness. The aurora is caused by charged particles hitting our atmosphere. It creates beautiful effects, but can also cause trouble.(Photo: Shutterstock / NTB)
Can reach Earth in less than a day
Space weather is constantly monitored by several satellites and instruments both in the atmosphere and in space. An example of a space weather forecast can be seen on NOAA's website.
Johnsen works on forecasts that indicate whether charged particles are heading towards us from the sun.
These clouds of magnetically charged particles can travel towards us at millions of kilometres per hour. If such a cloud is sent our way, it takes a few days before it reaches Earth.
That gives us some time to prepare.
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"The most powerful storms can reach the Earth in less than a day," says Johnsen.
These magnetic clouds can cause major problems for the power grid and other electronic systems on Earth.
The nightmare scenario is that these solar storms will affect our power grid. That could have serious consequences.
15 million customers were affected
In 1989, a massive power outage occurred in Quebec, Canada. More than 15 million electricity customers fell victim to a blackout that lasted eight to nine hours, according to Johnsen.
"One or two transformers were physically damaged," he says.
The geomagnetic storm can interfere with the way transformers normally operate, causing them to increase their own power consumption and their internal temperature to rise.
You can read more about what actually happens here.
This can cause them to break, but they also have mechanisms that allow them to protect themselves.
Johnsen explains that transformers can disconnect themselves from the grid.
"Statnett is most worried about several disconnecting at the same time," he says.
Statnett is Norway's state-owned operator of the national power grid. This scenario is described by Statnett's security director, Kjetil Sørli, in the Norwegian Broadcasting Corporation's (NRK) programme Catastrophe about solar storms.
Norwegian transformer disconnected due to solar storm
Johnsen has an agreement to notify Statnett of potentially disruptive space weather. A transformer in Trøndelag county has been disconnected several times since 2017 due to solar storms.
Geomagnetic storms can cause power outages in larger areas of Norway. This can lead to major societal consequences, according to this NVE report from SINTEF on measures before and during solar storms from 2021 (link in Norwegian).
It can take many hours before the power is restored, says Johnsen. He says that in the worst case, it can take longer if expensive and large equipment needs to be replaced.
