Datacentres in the dark: How the sector is preparing for the prospect of planned winter power cuts

The datacentre industry plays an important role in keeping the UK’s increasingly digital economy ticking over, with many facilities now classified as critical national infrastructure.

The work the industry does is notoriously energy-intensive and this is why operators are already mobilising in response to warnings about how the ongoing volatility in the European energy market could – in a worst-case scenario – necessitate planned power outages later this winter.

The National Grid ESO, the entity tasked with transmitting electricity through the UK energy system, published its annual Winter outlook document in October 2022, which sets out how gas and electricity supplies are likely to hold up during the cold winter months between October and March.

As stated in the report, this year’s outlook has been compiled against a backdrop of “unprecedented turmoil and volatility” in Europe’s energy markets caused by the destabilising impact of Russia’s invasion of Ukraine on continental gas supplies.

The situation has already led to hikes in the wholesale price of energy, which households and businesses across the UK are feeling the effects of, but could also lead to gas shortages this winter.

The report details the steps the National Grid is taking to ensure there is no disruption to supplies over the winter months, including the roll-out of its Demand Flexibility Service (DFS) from 1 November 2022, which financially incentivises smart meter users to reduce their energy consumption during peak periods.

It is hoped the DFS scheme will help to conserve gas supplies on particularly cold, non-windy days when energy demand typically increases and less renewable energy is being generated.

“Without the Demand Flexibility Service, there is the potential to need to interrupt supply to some customers for limited periods of time in a managed and controlled manner,” says the Winter outlook document.

But although described in the report as “unlikely”, there is a risk that if the energy supply situation in Europe were to escalate further, customers could still be impacted by supply interruptions – even with mitigations such as the DFS in play.

“All possible mitigating strategies would be deployed to minimise disruption,” says the report, but elsewhere gives further details about what a “managed and controlled” supply interruption would look like.

“In the unlikely event that we were in this situation, it would mean that some customers could be without power for pre-defined periods during a day – generally this is assumed to be for three-hour blocks,” it says. “This would be necessary to ensure the overall security and integrity of the electricity system across Great Britain.”

Part of the national critical infrastructure

And although this scenario is heavily caveated as being “unlikely” and “worst case”, it is a prospect for which the datacentre industry must prepare. “Datacentres are part of the national critical infrastructure and must remain operational,” says Ed Ansett, chair and founder of datacentre engineering consultancy firm i3 Solutions Group.

“Inevitably, there will be an increased rate of datacentre failures if utility blackouts occur. The ramifications will vary depending on who is affected and the duration and frequency of the utility blackouts.”

Ansett adds: “With the National Grid already issuing statements about possible planned blackouts in January and February, even if they are saying this is ‘an unlikely base case’, then hope for the best and plan for the worst is how datacentre firms are approaching this winter.”

“All possible mitigating strategies would be deployed to minimise disruption”
National Grid ESO report

Alex Rabbetts, managing director of the European Data Center Association (EUDCA), backs this view, telling Computer Weekly that operators would be wise to prepare for the worst because any amount of time they spend offline could be hugely damaging. 

“The ever-increasing dependence of all sectors of our economy and society upon digital services places heavy reliance on available and efficient datacentre infrastructure,” says Rabbetts. 

“To force providers to shut down for any period of time – even seconds – would be hugely damaging to the economy, to the country’s support infrastructure, and to the functioning of society in general.”

This is precisely why datacentres are designed and built to ensure uptime in any circumstances – including the loss of utility power, he says.

“Unless a datacentre is wholly dependent on utility power to operate, being told to shut down serves no real purpose in terms of grid capacity,” says Rabbetts. “Those writing influencing policy need to understand that simple fact.”

Preparing for the long winter ahead

Accordingly, many operators that EUDCA comes into contact with are already preparing for the long winter ahead by negotiating shorter delivery times for the fuel needed to power their backup generators in the event of planned blackouts, for example.

“Datacentre owners and managers will no doubt be readying themselves for potential impacts by topping up fuel supplies and testing all power protection systems to ensure their correct operation in the event that blackouts, no matter how unlikely, do occur,” says Rabbetts.

But the fact remains that larger operators are likely to be better prepared than smaller ones in the event of blackouts – planned or otherwise, he says.

“For major operators, who have the resources to build in deeper contingency plans – such as having enough diesel to run for up to a week – any potential power blackout will not have the same repercussions as for those smaller enterprises that may not have the same fuel storage capability.”

And ensuring they have ready and reliable access to additional fuel for their generators will be of critical importance if, for example, the government or grid operators were to order the sector to disconnect itself from the grid to help conserve suppliers this winter.

“We could be facing a situation where it could be the grid operator that tells datacentres to disconnect from the grid”
Ed Ansett, i3 Solutions Group

Ansett says: “If you are trying to solve this problem at government level and you have that resource available, it would be foolish not to entertain that idea. It is not beyond the realms of possibility that governments might say to datacentre operators: ‘This is not a request. We are going to force you to run off the grid at our command at times of constraint.’ This is quite conceivable.”

When Computer Weekly put this scenario to the Department for Business, Energy and Industrial Strategy (BEIS), a spokesperson issued the following statement: “The UK has a secure and diverse energy system. We are not dependent on Russian energy imports and have plans to secure supply and protect households and businesses, including datacentres, in the full range of scenarios this winter, in the light of Russia’s illegal war in Ukraine.”

The statement also made reference to the DFS scheme, and confirmed that a “similar scheme to reward voluntary demand reduction by the heaviest gas users is also being developed to support energy security”.

At the time of writing, no further details were available on what form this “similar scheme” may take, but Ansett says heavy energy users, including datacentres, could be financially incentivised to take part in demand response (DR) schemes to reduce the pressure their activities have on the grid.

There are several types of DR scheme that datacentre operators could be asked to take part in, with the “simplest and most obvious” one, known as load shedding or load curtailment, requiring operators to disconnect their facilities from the grid and run their sites off their backup generator capacity. 

“We could be facing a situation where it could be the grid operator that tells datacentres to disconnect from the grid and run their [backup] generators for several hours at a time of constrained capacity,” says Ansett.

There is also a chance that operators might be asked, wherever possible, to shift their energy-intensive workloads to run at off-peak times, although Ansett acknowledges that this form of DR is likely to be tricky for operators to engage in.

“IT workload power use is typically not something that can be controlled by wholesale and colocation datacentre operators,” he says.

There is another form of DR that sees operators export their site’s surplus energy back to the grid, although Rabbetts says that in his experience, very few datacentres are set up to work in this way.

“In order to return surplus power to the grid, a change in the infrastructure would be required, enabling the facility to feed the grid rather than taking power from it,” he says. “This would introduce a risk while the changes to the datacentre infrastructure were made. Customer appetite for this may be difficult to obtain.”

Rabbetts says that currently, although DR schemes like these are common in some countries, he is not “currently aware” of any government proposals being made to encourage the roll-out of similar initiatives in the UK.

However, Ansett is of the view that governments should be looking to adopt these ways of working to ease the pressure on the grid.

“There may be a case for some datacentres with excess or un-utilised generator capacity that they could be asked to feed that power back to the grid,” he says. “It won’t solve the problem, but if the datacentres disconnect, it could give the grid operators some headroom.”

As mentioned above, operator participation in DR schemes is currently very low, but the energy market’s supply and price volatility might force a change on that front.

Ansett adds: “The main issue with all of this is that most datacentre operators do not participate in demand response. However, this is likely to change and rolling blackouts might be the catalyst for widespread DR adoption.”