Scottish and Southern Electricity Networks (SSEN) agreed to pay redress payments after the review, which found customers in the north-east of Scotland faced “unacceptable service” following the storm in November 2021.
Many households had their power cut off for more than a week and faced poor communication from utility firms on when they would be reconnected.
Ofgem also found they were slow in delivering compensation.
The storm caused significant damage to overhead power cables and around 16 million trees were impacted.
Since the storm, SSEN has taken part in reviews as well as customer and stakeholder research.
It said it will seek to implement “any further lessons learned” for the coming winter and beyond.
SSEN has paid around £4.5 million in compensation above statutory levels and has agreed to pay a further £3.5 million, which will include a £1.8 million payment to local authorities in the areas affected most by Storm Arwen.
A further £1.2 million will be allocated for additional investment to protect key circuits and contingency measures which will help improve response times to future events.
Some £500,000 will be added to the SSEN’s community fund pot which will hand out awards this summer.
SSEN director of operations Mark Rough said: “Storm Arwen presented an unprecedented challenge for our customers, communities and our operation, causing damage to our network far greater than we had seen before.
We have already taken steps to improve our response through listening to our customers and will continue to implement any and all learnings for future events
Mark Rough, SSEN
“I’m very proud of the way our teams dealt with this challenge, often in extremely hostile conditions, but also recognise that customers would like us to do better still in restoring their supply more quickly.
“We have already taken steps to improve our response through listening to our customers and will continue to implement any and all learnings for future events.
“The additional £3.5 million in funding will support this aim, helping improve our operational response and support community members, particularly those most vulnerable, improve their own resilience.
“We will now work collaboratively with industry, community partners and policy makers to ensure the recommendations from today’s publications are appropriately reviewed, implemented and, where necessary, supported through the regulatory framework.”