Executive Summary
- John Booth, Managing Director of Carbon3IT Ltd and Technical Director of the National Data Centre Academy, explores the practical challenges of turning data centre waste heat into a useful resource.
- From legacy cooling infrastructure and district heating connections to commercial agreements and seasonal demand, Booth argues that successful heat reuse requires long-term planning and collaboration between multiple stakeholders.
- He also looks at what operators can do now to prepare for heat reuse, particularly when designing new facilities and engaging with local heat plans.
Turning waste heat into a useful resource
As data centre energy consumption continues to grow, so too does the focus on what can be done with the heat generated by these facilities. While waste heat has the potential to support district heating and other local applications, significant technical, commercial and planning challenges remain.
John Booth, Managing Director of Carbon3IT Ltd and Technical Director of the National Data Centre Academy, discusses why heat reuse is about more than simply recovering heat from a data centre. From legacy cooling designs and the need for local authority planning to the changing demands of AI infrastructure, he explains what operators need to consider if waste heat is to become a genuinely useful resource.
What are the main obstacles stopping operators from turning waste heat into something useful today?
Primarily, its a problem with legacy cooling designs, data centre heat rejection equipment is ususally at the roof of the building, whilst district heating equipment tends to be in the basement, that is a fundamental building envelope problem.
Secondly, due to the disruption involved in retrofitting district heat systems, digging up roads and laying pipes, there really needs to be a “masterplan” that involves the local authority, the district heating supplier and other local heat providers and offtakers, this is usually absent, although I understand that DESNZ is in the process of creating a “toolkit” for the use of industrial waste heat processes.
Thirdly, a lack of commercial contracts, colocation data centres cannot guarantee that they’ll be able to provide the heat long term due to customer churn and technology changes (although liquid cooling will change this), there is also a question of price.
Fourthly, seasonal variations, what do you do with the heat in the summer, secondary systems need to be installed to vent heat to the atmosphere when its not needed, unless there is a heat off-taker, such as a swimming pool or other low heat industrial process, it all goes back to masterplanning!
In essence, we can use data centre waste heat, but it takes a lot of planning and herding cats to reach an acceptable outcome, lots of stakeholders need management.
Data centre output is often low-grade warm air or water. How ready are local heating networks to take that on, and who usually eats the cost of the extra equipment needed to make it usable?
In the EU Code of Conduct for Data Centres (Energy Efficiency) Section 5.7, there is the “Capture Ready Infrastructure” best practice, it states “Consider installing ‘Capture Ready’ Infrastructure to take advantage of, and distribute, available waste heat during new build and retrofit projects.” There are also references to heat recovery in the TS EN 50600-5-1:2023 Data Centre Maturity Model Standard.
In the absence of official DESNZ guidance (although, I do expect to see something included in the forthcoming National Planning Policy Statement for Data Centres when it is finally published, due Oct 25, postponed to June 2026, still not published!) operators should consider allocating space and designing cooling systems that are in basement levels and provide space for heat pumps and District Heating Supplier (DHS) Equipment. The cost for the District Heating Equipent is usually borne by the DHS although there may be grants available in certain locations.
We see a lot of regulatory focus on efficiency now. Do current policies encourage actual adoption, or are they just creating compliance hoops for engineers to jump through?
We are in a climate emergency, this summer with 5 possibly 6 heatwaves and El Nino possibly going to cause a cold, wet winter, plus energy security means that engineers are going to have to get with the plot, we absolutely have to use the regulatory guidance and the ISO/IEC 22237, EN 50600 and the ISO/IEC 30134 KPIs to design and build our data centres. As mentioned earlier, we await the NPP statement for data centres but I expect to see more regulation and penalties for non-compliance. The EU Energy Efficiency Directive and its implementaton into primary and
secondary legislation has forced operators to adopt the efficiency best practices and in some cases they are compelled to, via their planning permisson requirements. In Germany, there are limits on PUE and a requirement to connect to a DHS.
But, it should be considered “the right thing to do” because DC operators will need to take communities with them and if they dont, then they are making a rod for their own backs.
Can existing legacy facilities realistically add heat reuse systems, or is this only practical for brand-new builds designed for liquid cooling?
As mentioned before, it depends on the design of the legacy facilities, but, with the growth of AI a lot of these facilities are no longer fit for purpose, and will probably have to be fully retrofitted or even demolished and rebuilt and if you’re going to do that, then you might as well design for the future.
If an operator wants to set up a working heat reuse strategy in the next few years, what should they sort out first?
Firstly, they should find out if the local authority has a “heat plan”, if so contact them to see whats going on and how they can assist, if not, then speak to them and suggest that it is a good idea (for energy security/climate emergency concerns) and bring together the interested parties.
DESNZ has already mapped out 19 Heat Zones and the coverage maps can be found on their website, if your data centre is located within or very close to those zones contact the person in charge and offer your assistance.
Then, I’d look to create a team to look into the technology, the regulations, the equipment providers and operators and perhaps attend some training.
