In parts of Södermalm and half of Gamla stan, street, traffic and residential lights went out at 19.09 on Monday evening.
According to Jonatan Björck, spokesperson for the network company Ellevio, 20,772 customers were affected.
He says that the fault first occurred somewhere in the power grid, but the automatic switching that should then take effect has not worked for some reason.
Then personnel must go out to a station and take manual actions.
One does not currently know what caused the power outage, says Björck.
It is something we will look at now ahead.
