Ways to marry data centre design with the sustainability imperative

How can data centres, generally perceived to be a carbon-intensive building type, be decarbonised? That was the topic up for discussion when experts in this booming sector gathered for a RIBA Journal roundtable discussion in association with Tate.

Chair Isabelle Priest kicked off proceedings with the startling fact that according to Techspot, data centres globally use the same amount of energy annually as countries such as Taiwan, Ireland, Denmark and South Africa. With demand for the facilities only set to increase, it’s all the more pertinent to look at how architects can help lower their embodied, as well as operational, carbon demands.

To do that, a grasp of the current context is key. A recent report on the typology by Cundall, cited at the event’s outset, showed that if a centre is powered by non-renewable energy sources, upfront embodied carbon is overshadowed by operational carbon. But in a future where renewable sources become the standard, upfront embodied carbon may account for two-thirds of a building’s life cycle O₂. In light of this, Tate’s Cian McGrath emphasised the importance of specifying low-embodied carbon products – Tate’s own included – as part of a suite of possible carbon mitigation measures for the sector.

Participants then set the scene by discussing the market trends for data centres over the couple of decades since they emerged as a new typology. The big difference now, said Dylan Bussey of Corgan, is that clients (such as banks, for example) are no longer end users, as they had been at the start of the century, but are instead cloud-service-providing tech companies.

Geographically, there has been a transition away from the first data centre hubs, including Frankfurt, Paris, Amsterdam and London, to wherever land and, crucially, sufficient power is available. Emerging markets include the Nordics, where the cool climate is advantageous, said Orlando Baghaloo of studioNWA.

‘Climate has a massive bearing on location,’ he said, adding that access to renewable energy is also increasingly important.

Another crucial factor is finding the right development conditions, including hospitable planning policies. Some countries, for example Scotland, have so far been more resistant than others such as Ireland.

Speed to market remains the main driver along with the basic priorities of sufficient power connections, floor-to-ceiling heights and a strong floor, according to PDG’s Gary Schofield, who has been designing data centres since 2000. The programme of accommodation has also remained generally consistent – data halls, electrical room, network room, admin space and back up energy system. The scale, however, has changed. At Corgan, for example, Bussey has worked on a data centre cluster of 30,000m² each. The trend is for multiple data halls, and this expansion has been driven further recently by the growth of AI use. Multi-storey data centres have also emerged – Baghaloo’s practice has been working on one as high as seven storeys.

So what can architects do to reduce embodied carbon in this super-size typology? Even small changes to the specification, for example the cladding, can at scale make a significant difference to the embodied carbon, said Madeleine Hilton of Gensler: ‘Because of the size of data centres, any change we make is very impactful.’

Architects are addressing this in various ways. StudioNWA has put together a repository of materials and their embodied carbon content for its clients, which would then guide the specification. ‘It’s important to look at a fabric first approach. As architects, that’s our influence,’ said Baghaloo.

There are other ways too. ‘The area we can have the biggest impact is site and site layout,’ said Richard Wilding of data centre specialist SNHA, which is designing 10-15 data centres. His colleague Nigel Rayner talked about looking for efficiencies that could be repeated thousands of times.

Architects need to get involved in ‘big picture things’ such as power and waste heat too, said Hilton: ‘These are the two biggest questions about sustainability.’

Any innovation has to contend with a risk-averse approach in a critical buildings sector where resilience is key. So getting the client on board is crucial.

‘Any change to how you deliver a data centre needs to assuage any fears that there’s a risk in trying something new,’ warned Bussey.

However participants reported that data centre clients were sophisticated and, like their design teams, keen to work towards 2030/2050 CO₂ reduction targets, with carbon performance increasingly part of their marketing material. This means they are open to looking closely at specifications of the internal zone, structural ceiling and hot aisle containments (HACs), for example, from this perspective.

‘Big data centre providers are ambitious. And as architects, we innovate with these clients,’ said Hilton, referring in particular to the need to make data centres ‘more palatable’ when building on urban sites.

Tate’s Debra Smith said incentives for clients to invest in low carbon materials ‘early doors’ were clear, and anticipated that more carbon targets were likely to come into the industry.

‘From a sustainability point of view and thinking strategically, it makes more sense to invest in lower carbon materials, because by doing so, projects can make meaningful, genuine carbon reductions,’ she explained. ‘Buying offsets is a route sometimes used to manage embodied carbon but it can lack credibility and transparency. In addition, carbon offsets are becoming more expensive year on year when collectively as an industry we should strive for lower carbon, locally sourced raw materials made with renewable energy and recycled content.’

There was recognition of the challenges of factoring transport-related carbon into calculations for a product’s embodied carbon, and the need for a methodology to define this. Even so, architects now have access to far more information on products’ carbon stats, according to Bussey.

So what would the ideal, more sustainable data centre be like?

‘I don’t think [the idea of] timber framed data centres is that far off the mark,’ said Bussey, adding that one was already being built in the Nordics. He said Corgan had been approached to research opportunities to use timber in data centres – including for the superstructure; there was potential for timber HAC.

Nigel Rayner of SNHA envisaged the use of glulam and CLT structures and raised the idea of a ‘prosumer’ data centre that was both a producer and consumer of energy, with waste heat serving district heating or other community uses.

His colleague Richard Wilding discussed the pros and cons of green walls to sequester carbon and encourage biodiversity. While these may be particularly desirable in more urban areas, the advantages had to be balanced with the embodied carbon of the steel structure required, and the maintenance of insects and foliage.

‘Is it the right thing for a data centre, that’s the question,’ he said, adding that such challenges in data centre design were ‘the dream’. He also raised the idea of more circular practices – could manufacturers, for instance, take back their products at the end of the data centre’s lifespan?

Baghaloo cited the potential of green roofs, green steel, a green growing medium for the data floor, bird-friendly buildings and trees in the car park – if there’s a willing client.

SNHA’s Rayner wondered if there might be opportunities to innovate in the manufacturing process, with the potential for on-site construction of components such as cladding. This could be a  way forward, rather than the carbon miles associated with off-site manufactured products.

Uncertainty over what the future might require is driving a level of ‘uber-flexibility’ in data centre design too: ‘No-one quite knows what’s coming next,’ Bussey said. Nevertheless there is a lot of optimism for decarbonising the typology and a general feeling that everyone is ‘on the same page’.

‘It’s encouraging to hear that architects and clients are treating this a lot more seriously. It’s no longer greenwash,’ said PDG’s Schofield.

‘As a firm we’re ambitious in our own carbon targets and sustainability agenda,’ said Hilton. ‘So we’re working with clients who are equally ambitious in what they want to drive forward towards that carbon-neutral endeavour. Running off a green grid, pumping heat back into the local community, zero waste – that’s the dream, and that’s what I want to get to.’

‘Research and innovation are crucial in a fast-growing sector. Data centre embodied carbon can be significantly reduced using sustainable building materials,’ said Tate’s Cian McGrath. ‘What is certain is that we can’t stop. We need to keep innovating, working collaboratively and sharing insights.’

Panellists:

Isabelle Priest, managing editor, RIBA Journal (Chair)
Orlando Baghaloo, associate director, studioNWA
Dylan Bussey, associate principal, data centres, Corgan
Madeleine Hilton, Birmingham office managing director, Gensler 
Nigel Rayner, architect, SNHA
Gary Schofield, senior technical consultant, PDG
Debra Smith, divisional sustainability manager, Tate
Richard Wilding, director, SNHA
Cian McGrath, commercial director – ceilings, Tate

This RIBAJ event is sponsored by Tate, www.tateeurope.com/eu/en/