"We don't know exactly what caused the error, but we are currently doing what we can to find out," Johanna Fridh of the energy company Geab told SVT Nyheter Öst.
The outage occurred at 6:51 p.m. on Monday. By 8 p.m., most Visby residents had their power restored, but around 2,900 households were still without electricity, according to Geab's website.
