Thousands of Berliners lost power for days after climate activists struck. Here’s what happened

<i>Ralf Hirschberger/AFP/Getty Images via CNN Newsource</i><br/>Some battery-operated Christmas decorations are seen in windows of a residential building in the Zehlendorf district on Sunday morning amid a power blackout.

By CNN Newsource

Published January 7, 2026 9:50 AM

By Sophie Tanno, Sebastian Shukla and Inke Kappeler, CNN

Berlin (CNN) — Amid heavy snow in the German capital and temperatures plummeting to below freezing, nearly 100,000 people were left without power for several days after an alleged left-wing arson attack on Berlin’s power supply on Saturday caused a major blackout.

The activist group Vulkangruppe – or Volcano Group – claimed responsibility for the attack, citing the role that fossil fuels and AI play in accelerating the climate crisis.

Roughly 45,000 homes and more than 2,000 businesses in Berlin’s wealthy southwestern districts were affected by the outage, which lasted more than four days.

The outage is believed to be the longest in Berlin’s postwar history.

What exactly happened?

The attack on Berlin’s power supply occurred in the early hours of Saturday morning, when a fire broke out on a cable duct over the Teltow Canal, which runs through the city’s south. The blaze damaged several high-voltage cables near Berlin’s Lichterfelde power plant.

Authorities put the fire out, but not before power had been cut at around 6 a.m. The outage affected up to 45,000 households and 2,200 business spanning four districts in southern Berlin, including Nikolassee, Zehlendorf, Wannsee and Lichterfelde, according to Stromnetz Berlin, the operator of the city’s electricity network.

The attack left people without power and heating amid nighttime temperatures of –10 degrees celsius (14 degrees Fahrenheit), disrupted overground train lines and hit mobile phone connections.

The Vulkangruppe later claimed responsibility for starting the fire, in a letter sent to police. “We successfully sabotaged the gas-fired power station in Berlin-Lichterfelde,” said the letter, which has been circulated online.

This, the group said, resulted in power outages in Berlin’s “affluent” neighborhoods.

Vulkangruppe apologized to the less wealthy residents of southwestern Berlin in the letter, saying that the goal was to target the fossil fuel industry and the action was a “necessary measure against the expansion of fossil fuel-fired power plants” in Germany.

“Power outages were not the goal of the action; the fossil fuel industry was,” it said.

“We know we must stop this destruction. We know we are not alone. Don’t give up hope for a world where life has space, not greed for money, power, and destruction,” it said, adding: “People call us eco-terrorists, yet we respect life. They call us irresponsible, yet we take responsibility to end this imperial, destructive way of life.”

Berlin mayor Kai Wegner told reporters Wednesday that the incident was “not a minor arson attack, not sabotage, but a terrorist attack by a left-wing extremist organization with massive consequences for the supply of many Berliners.”

German federal prosecutors said Wednesday they had opened an investigation into the incident, with suspected offences relating to membership in a terrorist organization, anti-constitutional sabotage and arson.

What was the impact?

An 83-year-old woman died during the power outages, according to deputy police chief Marco Langner. She was found by a relative, who called an ambulance, but emergency workers were unable to save her, Langner said Wednesday, without offering further details about the circumstances of her death.

He added that there had been reports of burglaries during the blackout.

In addition to the power outages in homes and businesses, the attack forced the suspension of train services on multiple lines of Berlin’s overground S-Bahn.

Mobile phone networks were also disrupted. Thomas Ohm, a resident in Nikolassee, told CNN: “Information came extremely late because there was no mobile reception and we did not know whether it was in Berlin and all of Germany or even worldwide.”

Five hospitals in the affected regions were forced to switch to emergency back-up generators. Stromnetz Berlin said power was restored to these hospitals by Sunday.

The electricity operator said the gradual restoration of power to customers began at 11 a.m. Wednesday, but warned residents against the use of high-powered electrical appliances immediately after power was switched back on.

One Berlin resident affected by the outage, Thomas Dastig, told CNN the experience was “creepy.”

“My coldest room was 4 degrees celsius (39 degrees Fahrenheit) and my warmest was 8 degrees celsius (46 degrees Fahrenheit)… I was afraid of my pipes freezing,” he said.

Another resident, Daniel Wöste, said he worked with his sister to organize generators to eight homes in their neighborhood.

“We especially looked after the elderly,” he said.

Domenico Castronovo, the owner of a small pizzeria in the Berlin district of Nikolassee, told CNN the outage had had “serious consequences” for many local businesses.

“Due to the interruption in our electricity supply, we were forced to temporarily close, resulting in the loss of large quantities of food and stored supplies,” he said.

A few kilometers from the affected areas, life continued as normal, with shops and restaurants open and fellow Berliners offering beds or showers to those affected.

In the wake of the attack, hundreds of police officers were deployed in neighborhoods affected by the outages, illuminating areas after nightfall with lighting masts, as well as establishing mobile stations. Police also set up a hotline for those affected.

Who are the Vulkangruppe?

The Vulkangruppe is a far-left extremist group in Germany driven by anarchist, anti-capitalist and radical environmental ideologies.

The group is known for carrying out arson attacks. According to Germany’s domestic intelligence agency, the BfV, the group has been behind several similar attacks targeting critical infrastructure since 2011.

In March 2024, the group claimed responsibility for a major attack on the power supply to the Tesla Gigafactory near Berlin, which forced production to halt for several days. The group published a letter online claiming it set fire to a pylon at the electric car factory after the attack.

CNN’s Chris Stern contributed to this report.