It was a once in a decade event which left more than 80,000 people without power and battered communities throughout Scotland.  

Last year Storm Arwen brought disruption and devastation to the power grid, felling trees and trapping isolated communities for days while engineers struggled to get them back online.  

But the ferocious storm which blew in at the end of November 2021 was just one of five ‘exceptional’ weather events to hit north of the border last winter, and energy companies have been preparing for more to come as this year’s season arrives.  

Lessons have been learned and millions of pounds spent on the network, but the expectation is that storms such as Arwen will be more frequent in future as the climate changes.  

Guy Jefferson, Chief Operating Officer, Scottish Power SP Energy Networks, is in charge of making sure a  network of power lines and substations stretching through central Scotland to St Andrews remains robust in spite of what the weather can through at it.  

Hundreds of miles over overhead lines, all vulnerable to the vagaries of the wind, supporting communities of customers dependent on Scottish Power’s vital services.   

HeraldScotland:

Mr Jefferson said: “The previous two years, we had maybe one exceptional event in each. Then we had five in one year. 

“We’re preparing for the worst, and hoping for the best, as I always put it.  

“We’ve got to prepare is if we’ve got another Storm Arwen this year and make sure that we learned any lessons we had to learn, and got things in place both in terms of what we always do, and in terms of building on top of that.” 

Storm Arwen, which was followed by Storm Barra, made landfall in the British Isles on 26 November last year and blew through Ireland Scotland and England before finally dying out across the Channel in France.  

READ MORE: Ofgem says power firms provided ‘unacceptable service’

Two people lost their lives and more than £40 million was paid in compensation by the power companies to customers left without power, some in the north east of Scotland - served by Scottish and Southern Energy (SSE) - for up to a week. 

Amid criticism of the length of time it took to reconnect households, SSE will adopt this year adopt a “reasonable worst case’ approach to keeping customers informed about how long they will be without power, to prevent expectations being dashed if an emergency drags on.  

HeraldScotland:

A spokesman for the company said: “Following the impact of last year’s exceptional storm season, SSEN Distribution has engaged constructively with BEIS, the Scottish Government and the regulator, Ofgem, as part of external reviews into Storm Arwen. 

 “We set up a dedicated project team to manage and prioritise the delivery of actions identified in external and internal reviews.  

“Alongside improvements to internal plans, processes and procedures, a particular area of focus has been on customer communication and embedding an Estimated Time of Restoration (ETR) communications process.” 

The company have also committed an additional £3.5million of funding to support customers and communities in the areas worst impacted by Storm Arwen. 

This money has paid for enhanced protection of key circuits and other contingency measures such as tree cutting, undergrounding of power lines and installing generation hook-up points at key locations on the 33 kilovolt ‘backbone’ of the network. 

HeraldScotland:

Chopping down trees is an unheralded part of guarding against storms, but falling foliage and wind-blown branches are often the biggest threat to the electricity network, not the wind.  

SP Energy Networks has spent millions from its annual £75m maintenance and resliliance budget on felling trees which could pose a danger to power lines.  

Guy Jefferson said: “We spend £5 million actually cutting trees, believe it or not. Because that was the main issue. It wasn't that our network wasn't robust – it was the trees falling over and going through our network (of power lines).  

“We also have a special regime to do winter checks over the course of September and October, where we do basic checks on the overhead lines that we know have caused issues in the past, and also our substations – making sure that everything is as it should be.” 

Predicting the weather is an inexact science, but power companies look to the future on a daily basis. Scottish Power receives daily forecast as well as three-day and five day predictions, so they “know what’s coming down the track”, Mr Jefferson said.  

READ MORE: SSEN customers set to get extra 20% compensation payment for disruption

This information is shared across the power companies, as are staff when the situation calls for it. Arrangements are in place for engineers and call-handlers from across the UK to be deployed to other companies if one area suffers an extreme weather event.  

HeraldScotland:

New technologies are being brought to the fore, with Scottish Power investing in LV (Low Voltage) Support Room, which helping pinpoint locations where faults might occur before they even happen. 

Pop-up pylons, which fit together like a giant Meccano set, can be rolled out and the increasing use of drones is allowing energy companies to survey damage to remote areas.  

Mr Jefferson said: “We use drones on the network to assess damage in a storm situation where sometimes you can’t get places because roads are closed, but you can get to places with drones. That’s been a real improvement.” 

But on the ground it is local communities who have been drafted in to help make a concerted effort to prepare for the worst of weather. 

Local resilience forums, comprising councils, police, emergency services, roads departments and the NHS, have been meeting regularly with the power companies to prepare for the storms to come this winter, wargaming scenarios such as those encountered when Arwen arrived.  

Mr Jefferson said: “That’s some of the things we’ve been exercising – what are the trigger points - in order to bring those groups together so we’ve got them ready to go when the likes of Arwen happens again. 

“We can work together to make sure that our customers and members of the public and vulnerable people have got the support they need when events like that hit.” 

Storm Arwen hotspots 

The high winds which came with Storm Arwen wreaked havoc across Scotland. Here’s where the hardest gusts were felt.  

Stornoway, Lewis: 92 MPH 

The village of Aultbea, Northwest Highlands: 73 mph 

South Uist: 76mph  

Loch Glascarnoch, Highands: 77mph  

Isle of Tiree: 68mph