During the last ten years data centres have made significant improvements in terms of sustainability and efficiency. However, legacy data centres remain one of the biggest obstacles in the industry’s mission to meet net zero. While new builds are inherently more sustainable than traditional builds, embodied carbon within the construction phase, and in particular, the embodied carbon of the infrastructure components, are key areas all operators must address.
Will Arnold, head of climate action at The Institute of Structural Engineers (IStructE), says that, for a typical building, most of the carbon emissions from that building are due to its operation, including heating, lighting, and cooling. However, as national grids decarbonise, these ‘operational carbon’ emissions are reducing. This means that the emissions due to the use of materials – known as ‘embodied carbon’ emissions – are increasing in importance.
Most of the embodied carbon emissions are due to the construction of the building structure. In fact, the concrete and steel used in construction contributes to over ten per cent of all global emissions – with bricks, aluminium, glass, and timber all adding to that figure. Understanding how to measure embodied carbon, and finding ways to reduce it while the data centre industry undergoes rapid transformations in both size and operational efficiency, should be a priority.
The Hierarchy of Net Zero Design
IStructE have developed a chart which explains the ways in which developers and construction companies can reduce their environmental impact considerably.
“The ‘Hierarchy of Net Zero Design’ starts with the need to use less stuff, because whilst you can choose between materials, there is very little you can do to specify your material in a way that will reduce global emissions,” asserts Arnold.
The ‘use less stuff’ section is broken down into sub-sections: build nothing; build less by repurposing or maximising space utilisation; build cleverly by implementing appropriate design criteria; build efficiently by constructing highly-utilised structures and using carbon efficient materials; and finally, minimise waste.
It is only then, after all of those points have been covered, that designers should specify low carbon and, finally, offset emissions which cannot be avoided.
Retrofit data centres
As the ‘Hierarchy of Net Zero Design’ shows, the most effective option is to use less new material (‘use less stuff’) by prioritising reuse of existing buildings, and designing new buildings as efficiently as possible. According to Marc Garner, vice-president of the secure power division and major pursuits team at Schneider Electric UK & Ireland, modernisation, or ‘retrofitting’, provides significant opportunities to reduce embodied carbon.
To address this within a facility that is in dire need of modernisation, legacy components, such as a UPS, can be replaced with a more sustainable or Green Premium solution, whereby the embodied carbon of the product is clearly labelled, and the components used within sourced in an ethical and sustainable way. This gives the user complete transparency and enables them to account for the lifecycle emissions of the product.
Other systems can also be addressed in a similar way, but Garner says that it is important to remember that one of the most significant contributors to embodied carbon in buildings is concrete, which often accounts for as much as 40 per cent of a data centres construction.
“In legacy facilities, this can be very difficult to address, but conversely, in new data centre builds, utilising sustainably sourced concrete, or a steel-structure-based design can deliver estimated carbon emissions savings of up to 13 per cent.
“What is clear, however, is that whether building from new, or retrofitting a facility, we must design the data centres of the future with sustainability in mind, and that embodied carbon is something all owners and operators must pay greater attention to.”
A recent blog post from 1547 Critical Systems Realty highlights some of the reasons for operators to consider retrofit facilities. According to the post, retrofitting an existing commercial building can result in a highly efficient and effective data centre environment, and it can also save budget and time to deployment. But when discussing the factors which operators should consider when deciding to retrofit an existing building (the likelihood of natural disasters, what infrastructure is already in place, and connectivity and power requirements – all good commercial reasons), the reduction of embodied carbon compared to a new-build is absent as one of those primary considerations.
More work is required, then, to make sure embodied carbon – and reducing Scope 3 emissions in their entirety – play a larger part in data centre operational strategy going forward.
Developing low-carbon materials
There is a limit as to how much less material you can use, however. Arnold says that as high as a 50 per cent reduction in material compared to business-as-usual may be possible if the client demands it, and when the whole design and construction team pull together. However, 50 per cent is only half the journey – how do we continue our trajectory towards zero? For this, we need lower-carbon materials.
Earlier this year, RWE and ArcelorMittal signed a memorandum of understanding to work together to develop, build and operate offshore wind farms and hydrogen facilities that will supply the renewable energy and green hydrogen required to produce low-emissions steelmaking in Germany. Meanwhile, engineers from Cambridge University were awarded new research funding for their invention of the world’s first emissions-free route to recycle Portland cement. This is merely a snapshot of the innovations designed to kickstart the decarbonisation of hard-to-abate industrial sectors.
But while many suppliers offer ‘low carbon’ versions of their material at a scale that can be taken to site today, they usually currently import supplementary materials whose supply is constrained globally. These supplementary materials would also have been used by someone else at source if not bought by the supplier, meaning that global emissions do not decrease when you specify that material.
Additionally, methods of reducing the carbon intensity of building materials such as concrete and steel are just not credible at scale at present.
“Whilst all materials industries are talking about how they intend to reduce the greenhouse gases emitted when they make those materials, most of these plans are far away from the trajectories set out by the IPCC as what we need to meet 1.5°C,” explains Arnold. “Many plans also rely on carbon capture and green hydrogen – technologies that are unproven at the scale being talked about, and that are already in huge demand and massively expensive. So, we need increased R&D funding, policies that accelerate innovations from lab to site, and standards that enable innovation at the speed required by the climate emergency.”
It seems, then, that we are still at the beginning of our journey to reducing embodied carbon emissions in the construction industry. But every journey starts with a single step and, with new carbon accounting measures coming into effect and discussions on the topic taking place across the industry, there are reasons to remain positive that the problem can and will be addressed.