Traffic lights went out causing disruption on the roads
A fault at an electricity sub-station left much of the west of Scotland without power.
Scottish Power said the problem at the Windyhills sub-station affected areas from Glasgow to Oban in Argyll.
Traffic lights were out at many locations causing rush hour disruption. Subway stations had to be closed as lights and escalators were not working.
The fault occurred at about 1620 GMT. Most of the power had been restored by 1800 GMT.
The biggest problems appeared to be on the roads in the west of Glasgow, Bearsden, Milngavie and Clydebank, where traffic lights went out, causing widespread disruption.
Strathclyde Fire Service said it had experienced a high number of call-outs due to alarms being activated by the power cut.
It also reported a high number of lifts which had jammed but said there had been no serious incidents.
Yorkhill hospital in Glasgow was without its main power supply for a period.
Delays of 45 minutes were experienced on the West Coast mainline and other train lines were affected.
Strathclyde Partnership for Transport said Partick and Kelvinhall subway stations had been closed after they were affected.
Scottish Power apologised for the fault.