Bosses at the airport – Scotland’s busiest – moved to reassure travellers after the outage caused widespread disruption just days before the start of the busy school holiday season.
The incident, which happened at around 9am, saw operations inside the terminal grind to a halt as passengers stood in darkness unable to check in or pass through security.
Queues could also be seen building outside as travellers continued to arrive in their droves, with power eventually restored around 50 minutes later.
Airport officials said they were investigating the full cause of the incident, which also caused back-up power systems to fail.
A spokesman said: “We lost power this morning due to a power outage on our high-voltage supply which knocked out the main supply to the terminal. The fault also prevented our back-up system from operating. This was caused by a catastrophic failure in one of our transformers.
“We are currently working to understand the full cause of the issue and why the redundancy didn’t function as designed.”
Airport staff were left dealing with a large backlog of passengers, with some flights delayed by around three hours as a result of the incident.
Some passengers who landed during the power cut had to wait on the runway for over an hour before they were eventually allowed to disembark.
Ian Marr, 50, who was returning to Edinburgh from a business trip in Amsterdam, said he and his fellow passengers had to wait an hour and a half before being allowed off the plane.
He said: “We were told we couldn’t get off the plane as passport control was too busy.
“They kept us on the plane until about quarter to twelve, which was about an hour and a half.
“People were frustrated. We were told it would be about ten to 15 minutes but then nothing happened. The pilot and the crew were trying very hard.
“They took us through a corridor but all the doors were locked so they had to get an electrician to get the covers off the locks.
“After all that when we got to passport control there was no-one in the line. It just seemed chaos – no one knew what they were doing.”
Sheila Smart, 57, had to wait in a plane on the runway for about 45 minutes before passengers were able to get off.
She said: “They told us while we were in flight that there was a power cut so we had to circle for around 20 minutes before we could land.”
Ms Smart was met outside the terminal by her cousin Pam Wight, 60, from Whitburn in West Lothian.
Ms Wight said: “I thought it was a bomb scare or something like that but then my daughter phoned me to say it was a power outage.
“I asked a couple of people what’s going on and they have been quite helpful. Nobody seems to be jumping up and down anywhere.”
Airport staff could be seen handing out free bottles of water to waiting travellers as they stewarded people into the airport in groups.
Mike Hellier, 62, said he was pleased with how the airport had handled the situation as he queued to check in for a flight to Exeter.
He said: “I didn’t expect to come in and be in quite such a long queue. Because the PA systems weren’t working there was a lack of information [but] they seem to have done quite well. There were people coming up the line telling us what was happening so I’ve been pleased with the way they responded.”
Emergency lighting was in operation inside the terminal throughout the incident, with passengers reporting a lack of running water had left toilets out of action.
Following a “test call”, an announcement delivered an apology to all passengers for the loss of power, saying an “ongoing fault” was to blame and airport staff were hoping to rectify the issue “shortly”.
The airport is the sixth busiest in the UK, handling more than 12 million passengers a year.
Gordon Robertson, director of communication at the airport, praised staff for their “team effort” and thanked passengers for their patience.
He said: “Everyone in the airport has been helping passengers and the passengers have responded really well, they have been really patient [and] understanding.”