Sri Lanka hit by islandwide blackout for about six hours; surplus solar suspected

Sri Lanka suffered a complete failure of its national electricity grid on Saturday, 17 October, leaving the country of about 22 million people without mains power for several hours. Supply was brought back region by region, and by late evening the National System Operator (NSO) said the transmission network had been fully restored, according to Xinhua.

When it happened and how long it lasted

Reports differ slightly on the timing. EconomyNext and Newswire said the system failed on Saturday morning, while an AFP report carried by IOL put the start at around noon local time. AFP said power returned in phases across the island towards dusk, putting the outage at about six hours. By mid-afternoon, Newswire reported, supply had come back in parts of Colombo, Gampaha, Galle and Badulla.

• Scale: islandwide, about 22 million people affected
• Duration: about six hours, per AFP
• All three units of the Norochcholai coal power plant went offline after the failure, plant management told Newswire
• Rooftop solar owners were asked to switch off their systems until further notice

What caused it

Local outlets described the event as a total system failure brought on by instability in the grid. Officials quoted by AFP said the grid probably tripped because solar output exceeded consumption at a time of low weekend holiday demand. Energy Minister Anura Karunathilaka said the cause was still being investigated, according to AFP, and appealed to rooftop solar owners to disconnect, saying supplies would be restored “stage by stage”.

According to AFP, Sri Lanka has slightly more than 3,000 MW of installed solar capacity, while daytime demand typically sits between 2,000 MW and 2,500 MW. Tax incentives have encouraged households to install panels and sell surplus power to the grid, which has made balancing supply harder for the utility.

Not the first time

The island’s grid shut down in a similar way in February 2025, also on a sunny weekend with high solar generation, and it took more than six hours to bring supply back then, AFP noted. EconomyNext reported that the Ceylon Electricity Board Engineers’ Union had at the time linked that failure to large volumes of rooftop solar, though no official finding has yet been made on Saturday’s outage.

The NSO said it would issue further guidance to rooftop solar users once the grid returned to normal operation, Xinhua reported.

Sources: Xinhua, EconomyNext, Newswire, The Star (AFP), IOL (AFP)