Data centres could be hot properties

Heat networks are set to tap into the waste heat from data centres for the first time in the UK. Lucinda Dann looks at the potential and challenges of recovering heat from this sector, and the other options for harnessing its power.

The UK’s transition to a net-zero future will create huge quantities of data through the use of smart appliances and electric vehicles, super-charging a sector that has already seen rapid recent growth because of the shift to online working as a result of the Covid pandemic. The expected uptake of AI will only grow the UK’s data centre industry – already one of the largest in the world – further.

Given the UK’s data centre sector already equates to around 4% of the country’s total electricity usage, it has unsuprisingly come under scrutiny for its part in taking valuable connections capacity in congested parts of London. But there is an opportunity to harness the power of data centres, as the vast majority of its electricity use is lost to the atmosphere in the form of waste heat.

This waste heat, produced through cooling data racks, could be reused in heat networks to heat homes and buildings. The idea is in its primacy globally, but moves are afoot in Europe to mandate heat reuse and the government’s plans for heat network zoning could see similar obligations put on the UK sector.

The first scheme aiming to repurpose waste data centre heat received funding from the government last year, but while the data centre sector welcomes any opportunity to get closer to net zero, it has concerns around mandating heat reuse. Instead, another viable option could be using their essential backup batteries in the flexibility market. Here, Utility Week explores the potential for both options.

Exponential growth

The clear one-way trajectory has meant questions have started to be asked about how the increasing consumption by data centres could be turned from a challenge for the energy system to a benefit.

Matt Wegner, postgraduate researcher at London Southbank University, believes data centres currently use 4% of the UK’s total electricity demand, which could produce enough waste heat to meet 3% of the UK’s demand for heating and hot water.

However, Luisa Cardani, head of data centres programme at TechUK, says it is very difficult to know what the sector’s exact usage is because co-location data centres – where rooms or data racks within a building are used by different companies – are usually subject to non-disclosure agreements (NDAs) – and their electricity usage will vary depending on the business type, with AI and machine learning having a higher power requirement. Even less is known about enterprise data centres, which are centres that are owned and operated by one company such as Netflix or Google.

However, Cardani says co-location centres in Europe will be forced to disclose their electricity use by the EU Energy Efficiency Directive, although she says it is not yet clear how such data will be collected. Data centres here will not be subject to the same rules, but attention has started to turn to just how much power the sector requires.

Last year the sector was wrongly blamed in the media for blocking housebuilding in certain areas of London after the Greater London Authority wrote a letter to Scottish and Southern Electricity Networks (SSEN), National Grid Electricity Transmission (NGET) and National Grid Electricity Systems Operator (ESO) about the insufficient electricity capacity in west London.

But while there are other factors, it is true that Slough and West London have become a major hub for data centres due to their proximity to the fibre optic networks that cross the Atlantic, and while this means there is competition between data centres and houses for grid connections, it also means that there is potential for waste heat from data centres to be used to heat these new housing developments.

Wegner says there is “plenty of potential” for heat recovery both from existing data centres, and also for cooling to be provided back from heat networks, and those likely to be built in the future, but acknowledges that there are barriers that will need to be overcome.

“It’s all down to the flexibility of everyone involved to get us to the scenario where we could recover the heat. There are a lot of barriers but none are completely inhibitive and by working together, a lot can be achieved. It’s about making sure everybody gets out a benefit.”

Location of data centres to housing and other landmarks such as motorways is one of the biggest factors affecting if a scheme would be able to go ahead, but professor of heating and cooling at London Southbank University Graeme Maidment says another significant barrier is the lack of familiarity in the UK with purchasing heat from a neighbour rather than an energy supplier.

“Technically it’s doable, depending on the physical constraints such as being able to distribute pipework and position equipment, but the challenge is it’s different to how we currently operate. We are familiar with buying our energy from a utility provider. In a scheme like this we are affectively trading energy with our neighbour, and that is great but we are not particularly set up to do that.”

Maidment says it will take deployment and visibility of that deployment to be able to reuse data centre heat at scale. “It will take time and a number of lighthouse projects like we are seeing to sort the technical and commercial details. It’s definitely very doable but it’s different to how we currently work and so it will take visible deployment of heat recovery to be able to be replicate it on a wide scale,” he says.

There are 23 data centres in the Netherlands which are already piping their waste heat to heat networks, with the UK falling behind largely due to the age of its data centres and the need to retrofit heat recovery equipment, says flexibility aggregator Enel X’s manager for strategic partnership Lucy Page.

But the first housing scheme to be heated by data centres in the UK has just been awarded £36 million in funding by the Green Heat Network Fund. The Old Oak Park Royal development in the London Borough of Hammersmith and Fulham will connect 10,000 new homes and 250,000m2 of commercial space to data centres which are currently in the process of being built.

A spokesperson for the project said data centres had been chosen as the heat source for the new network after feasibility studies identified data centres as the most viable and therefore best carbon neutral solution within the nearby area. They identified finalising commercial agreements between data centres and heat customers as one of the main challenges that needed to be overcome for the project to move forwards.

These commercial arrangements include deciding whether or not the waste heat should be sold or given away for free, as is the case in the Netherlands. Such issues have been addressed in the GreenSCIES project, which is an alliance between London Southbank University, Innovate UK and the London Borough of Islington to secure a low-carbon future for Islington, and now exists as a centre for excellence.

A detailed technical analysis was undertaken as part of the GreenSCIES project, says Maidment, to prove on paper that the commercial case made sense. He says that based on that analysis, his view is that both heat and cooling are two important revenue streams, amongst others, in making such an enterprise economically and commercially viable.

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