Executive Summary
- For data centres, prepping for winter means more than a boiler service, some hot water bottles, and a double duvet.
- Research shows that 20% of storm related power outages last more than 24 hours, and lack of power accounted for more than half of impactful data-centre outages in 2024.
- Will we have enough power for our data centres this winter, and what are the other risks that we need to build resilience against?
This weekend I brought my waterproof walking boots out from the garage, placed a crocheted pumpkin in the windowsill, and even wore a woolly jumper for the first time in about six months. The heavy tog duvet is still in the loft, and it’s too mild to turn on the heating (much to my partner’s relief), but there’s no denying, winter is on its way.
Data centres can’t put on an extra thick pair of socks or cuddle up to their pets when the weather turns cold (remember when that was actual advice given?) but the darker months do throw up their own challenges for the sector, and I want to shed some light on what that actually means…
I’ve got the power – or do I?
If I know there is a chance of a power cut, my preparation is fairly basic. I make sure there are some candles in the cupboard, charge all my devices and, if things look particularly grim, make sure there is enough gas for the camping stove – and some Pot Noodles and plenty of Coco Pops. A data centre has to do a bit more.
Currently, the outlook for this winter is reassuring. The National Energy System Operator’s early view of Winter 2026/27 expects Great Britain to have enough electricity to meet demand, with a forecast surplus of 5.5GW, equivalent to an 8.8% buffer over expected peak demand.
NESO says the electricity system is expected to remain secure and reliable, although it will continue to monitor weather conditions, global gas markets and European electricity flows.
On the other hand, the Climate Change Committee’s (CCC) latest assessment says power-system failures were responsible for more than half of impactful data-centre outages in 2024.
It is careful to say that it isn’t currently possible to separate climate-induced power failures from other causes, but the CCC also says that storms tend to produce longer-duration power outages than other causes. Research found that around 20% of storm-related outages lasted more than 24 hours, compared with 1% outside storm events.
Fail to prepare and…
As well as being a cereal prepper (see Coco Pops), I’m also a serial planner. But, looking ahead at the next six months, I’m only using pencil on the calendar for any events or meet-ups I have to drive to, or catch a train for, just in case.
If the roads are icy, the rain is torrential, or goodness forbid, we get that ‘wrong type of snow’ again, I work from home and can walk to almost anything I would ever need: shops, post office, cinema, gym (not that I ever do).
A data centre can have backup power, batteries and generators, but there is still a world outside the gate.
We tend to picture a data centre as a beautifully engineered, self-contained building. It has redundant power, backup generation, multiple network connections.
But it isn’t an island.
The Climate Change Committee identifies flooding and high winds as significant hazards for digital and telecommunications infrastructure, while also highlighting data centres’ vulnerability to flooding.
A generator might be ready. The fuel might be available. The data centre itself might be perfectly capable of continuing to operate.
But if the road delivering the next fuel load is flooded, or the engineer who needs to reach the site can’t get through, resilience suddenly becomes a rather bigger concept.
Keep your data centres close
My locale has excellent amenities and I have excellent wellies, so there’s no chocolate craving that can’t be met when the weather turns. Data centres like to be close to the action too (if you can call a well-stocked sweet shop ‘action’, which I do).
Our data centres want access to customers, connectivity, networks and existing infrastructure, and being close to economic hubs can help minimise latency.
The Climate Change Committee says around 80% of UK data centres are located around the M25, with a second significant cluster around Manchester. But it also warns that this concentration can increase vulnerability to climate hazards because one event can potentially affect multiple sites at the same time.
If I’m close to everything I need, bad weather can actually make life easier because I have options.
But if several data centres are connected to the same infrastructure, located in the same region and exposed to the same weather event, does being close together make the industry more resilient – or more vulnerable?
The optics of “my lights aren’t working, why are theirs still on?”
Last but not least… The house is dark. The heating isn’t working. The candles are out. The Pot Noodles have been retrieved from the back of the cupboard. Down the road, the data centre is still humming away.
From inside the facility, that’s a success story. The resilience systems have done exactly what they were designed to do. From outside the fence, it might look rather different.
That doesn’t mean a data centre running on its own backup generation is somehow taking electricity away from the homes around it. But we know perception matters, particularly when data centres are already part of a much wider conversation about electricity demand and access to the grid.
Ofgem said in July that demand connection applications had risen from 41GW to 125GW in less than a year; with data-centre projects accounting for at least 80GW of that demand.
The regulator has proposed measures intended to tackle speculative projects occupying scarce grid capacity.
So there is a slightly uncomfortable question here.
When people are sitting in the cold and dark, does a huge facility that is still operating simply look like another reminder of how much electricity these buildings consume?
Winter is coming. What are you doing?
My personal winter prep is almost complete – and personally, I can’t wait for cosy nights in front of the TV, reading by candlelight, and slow cooker stews.
But what about the data centre industry?
Here’s what I see on the surface… The national electricity system can have enough capacity while a local network experiences an outage. A data centre can have backup generation while the road outside is flooded. A site can have fuel available while the wider supply chain is struggling. And a cluster of highly resilient facilities can still be exposed to the same regional event.
I’ve done my own digging, but I’m looking at resilience from the outside (or rather ‘inside’ my warm, fluffy blanket bubble)…
So, over to you.
What are you doing to get your data centre through the winter?
