Data centre growth seen in scaled schemes and retrofits

According to a recent Rider Levitt Bucknall (RLB) report, the data centre sector's energy consumption is considerable – and still growing.

The International Energy Agency found that, in 2022, the world's data centres used 460TWh, equivalent to powering more than 8m homes. This figure could more than double to 1,000TWh by 2026, roughly equivalent to the annual energy consumption of Japan.

As a result, small, medium and large data centres will need to be developed rapidly to meet demand in coming years.

While there is no accepted definition, a hyper-scale centre is generally considered to be one that can support in excess of 40MW of computing power or more than 5,000 servers, and has a minimum of 1,000m² of data hall space.

The key metrics are the power and cooling that the servers require. The amount of servers that can be supported varies greatly, given that consumption can vary from 200kWh to more than 1.5MWh depending on the number of CPUs, cores and fans, the size of RAM and so on.

The floor area is therefore the least reliable metric. A 40MW data centre, for instance, may actually need somewhere between 10,000m² and 12,500m², much more than the 1,000m² minimum.

Major cloud computing providers  and specialist data centre developers are even building 90MW data centres, comprising three, four or more buildings on a campus.

However, not all data centres are hyper scale, and many successful developers build high-power, highly resilient facilities for customers requiring smaller-scale space to host their IT platforms.

Having worked in the sector for many years, I have found that such centres are designed to the same standards and specifications, or sometimes even higher, than those built directly by hyper-scale cloud providers.

• The proportion of net data hall space – or white space, as the sector calls it – is generally 40–50% of the gross internal area, excluding any office blocks. This allows room for all the critical mechanical, electrical and plumbing (MEP) infrastructure.
• Power and cooling loads are typically 2,500–4,000W/m² of net data hall space. A mid-sized 30MW centre at 3,500W/m² requires 8,570m² of net white space, and a gross internal area of between 17,140m² and 21,425m².
• Significant, dual power supplies ideally need to be close to the data centre; that is, two main connections to the local grid, sourced from independent substations or connection points, so that if one goes down there is another to ensure resilience.
• High-speed fibre networks should be accessible, and the more carriers are available the better.
• Noise and emissions of nitrogen oxides, carbon dioxide and diesel particulates from generators and heating, ventilation and air conditioning (HVAC) plant can be an issue in urban environments, and must be managed effectively.
• IT racks, MEP services and HVAC generally need 8–9m between the structural floor slab and the structural ceiling or soffit.
• Foundations, structural frames and floors must be strong enough to handle loadings of 10–15KN/m²; for comparison, offices might only handle loads of 3–5KN/m².
• Columns must be spaced in such a way as to maximise useable floor area in data halls.
• Roofs may have to bear significant weight from HVAC or heat rejection equipment.
• The physical distance between pieces of equipment must be minimised to reduce system losses such as voltage drops between switchgear and connections to IT racks.
• Significant external space is necessary for HVAC, medium-voltage electricals, stand-by power generation systems and bulk fuel storage; generally, this will be 30% or more of a data centre's gross internal area.

Developers of small and medium-sized data centres are therefore looking to convert existing premises, with industrial warehouses, logistics distribution centres and industrial or manufacturing spaces being among the preferred options.

Logistics centres are particularly well suited to this as they fulfil most of the requirements in terms of size, clear spans, external space and existing hardstandings for MEP plant, as well as having capacity to add internal structural floors to create at least two data hall levels, and access to major road and transport networks.

Manufacturing buildings that have large, open floor spaces with good slab-to-slab heights, load-bearing capacity and external space also make good candidates for conversion to large or hyper-scale use.

From my experience on numerous retrofit projects, including the conversion of a disused chocolate factory into a data centre in Sweden, there are a number of key items to keep in mind on any site:

• level and availability of high- or medium-voltage power in the local networks
• the fact that new power supplies can take two to three years and cost more than £1.5m per kilometre to install
• the location of main fibre nodes for the site and the number of carriers available
• the extensive work likely to be necessary to support the installation of HVAC on warehouse roofs, which are generally lightweight, if such equipment can't be sited elsewhere
• proximity of residential or noise restriction areas.

If the size and structural design of an existing building is too constrained, it is often more cost-effective to demolish it and rebuild a bespoke shell rather than compromise the critical MEP infrastructure design and building efficiency.

Although they are designed to connect to large or hyper-scale facilities, edge data centres are located closer to end users to improve bandwidth and reduce latency, or lag, in digital services provided over the internet, such as 4K video streaming, 5G mobile communication networks or connected vehicle technologies.

Lower latency and higher data throughput are the key factors in minimising processing times and improving customer experiences. Edge centres therefore take some of the strain off the larger facilities, make more efficient use of processing resources, and allow for quicker response times.

Such centres range from 250kW to 5MW in computing power, typically feeding 20–100 IT cabinets that each hold around 40 servers.

They also lend themselves to modular designs, require less physical space and standby power and use smaller HVAC systems, all of which can make them easier to deploy in urban environments.

With less intensive power demands, edge data centres can also ease issues with back-up generator installations, power connections, noise and emissions associated with their bigger cousins.

This makes them more suitable to install in other building types, such as former commercial offices, residences, public buildings and smaller industrial units.

Key items for a potential edge data centre location include the following:

• access to high-speed fibre networks for connections to large or hyper-scale data centres
• proximity to mobile communication network nodes
• availability of stable power connections and dual supplies
• single-storey buildings with large floor areas, or multistorey buildings with large ground-floor areas
• sufficient external space for critical MEP equipment, systems and fuel storage
• ease of making the site physically secure
• permits or planning restrictions on noise and emissions for MEP plant
• proximity to transport networks and hubs for staff.

In fact, recent research by RLB showed that data centre operators are expected to commission 65% more capacity this year.

Therefore, understanding the way we accommodate data centres is key to masterplanning not only our rural areas, where there is land to build, but also our cities, where connectivity is needed.

Conversion of unused residential or commercial buildings is often the most efficient way to integrate edge data centres, while disused warehouse space or new builds might be more suitable for larger, hyper-scale projects.

Recognising the requirements and aligning these with the locality can help the sector to progress.