Shops and restaurants plunged into darknesspublished at 12:59 British Summer Time
Guy Hedgecoe
Reporting from Madrid
The power outage began soon after midday Spanish time and it appears to have affected cities across the country, although the Balearic and Canary Islands do not appear to have been affected.
Mainland Portugal and Andorra also saw a similar blackout.
Public transport has been disrupted, with passengers evacuated from trains and traffic lights also affected.
In Madrid, many businesses, shops and restaurants were plunged into darkness. Internet service was also affected.
Spanish grid operator Red Eléctrica has said it is working with energy companies to restore power.