With green credentials now top of many customer’s agendas as well as the need for data to be processed closer to the source, Ali Fenn, president at ITRenew, explores ways to optimise sustainability in edge data centres in order to satisfy these growing demands.

Edge infrastructure brings crucial new compute, storage and networking capabilities to businesses and communities across the globe. It also brings new challenges. Distributed data centres come in all shapes, sizes and form factors, developed to address varied business needs, workload priorities, footprints, environmental conditions and regional constraints (both geographic and regulatory).

This means operational efficiencies, common in purpose-built core data centres, are not available at the edge. And it means more non-traditional data centre operators will be deploying solutions in market.

The imperative for sustainability will also play out differently at the edge. It will need to encompass new models for efficiency, a holistic look at the carbon impact of IT infrastructure, and both consumed and avoided emissions. Circular economic models, with their financial and environmental benefits, will continue to help guide the data centre industry to meet the crisis and leverage the opportunities at the edge.

Rapidly expanding 5G and IoT services and applications are having a significant impact on every aspect of our lives. Not coincidentally, they are changing how data centre operators and a plethora of new infrastructure deployment constituents deploy their capacity.

Companies are building facilities at the edge much closer to their operations, and the people they serve, to meet bandwidth and latency requirements, and leveraging a multitude of existing spaces from public to private to outdoor. These proximal edge deployments provide local processing and storage, but will inevitably look and feel quite different from traditional core data centres.

By operating close to where the world lives and works, edge data centres and compute infrastructure are often located in structures that are not purpose-built for housing IT hardware. New formats are emerging such as modular data centres in shipping containers, and micro data centres integrated into cell towers. Some are rack-based, others are small form factors, sometimes further integrated into ruggedised chassis.

With more diverse locations and formats than the core, edge data centres will require their own strategies for sustainability. New opportunities for reducing total carbon impact come into play based on the facilities’ local regions and cultures.

Lower PUE and renewable energy are the first step

A decade ago, data centre sustainability was foremost a matter of reducing electricity usage. Led by the world’s largest cloud services companies, also known as hyperscalers, operators developed highly efficient technologies such as DC power distribution and cooling strategies to drive down power usage effectiveness (PUE) and thereby minimise associated Scope 1 and 2 footprints.

However, such specialised techniques as these are difficult to replicate across a large number of smaller, distributed edge data centres. Therefore, PUE is not seen as the driving criteria for achieving sustainability at the edge.

Having driven down PUE, the data centre industry moved to become more carbon neutral by buying renewable energy credits (RECs) and employing other financial mechanisms to offset their Scope 1 and 2 emissions. In the last few years, many have actually committed to running their facilities on renewable power.

Edge data centres can and should also use renewable power wherever possible, but contracting green energy for widely distributed facilities is significantly more complex than doing so for one large core data centre.

The industry is committing to these measures through efforts such as the Climate Neutral Data Centre Pact, an industry association of European cloud and data centre operators including AWS, Google and Equinix as well as smaller and national providers, and backed by 17 industry bodies.

These operators are dedicated to becoming climate neutral by 2030 by various means, such as a target PUE of 1.3 in cool climates and by matching electricity demand with 100% renewable energy. As they diversify their operations to include more edge data centres, their practices will help to make edge data centres more efficient as well.

Moving past Scope 2 to Scope 3 emissions

More importantly, the members of the Pact are committed to innovating their operations for a circular economy model. To that end, they will assess 100% of their used server equipment for reuse, repair or recycling by 2030.

This is the next frontier in sustainability. The sourcing, manufacturing and transportation of IT equipment is a significantly greater contributor to net carbon emissions (as much as 75% of embodied carbon) than the ongoing data centre operation.

Reuse of existing data centre hardware has a direct and substantial impact on their sustainability. For example, extending the life span of IT equipment from the typical three-years in a hyperscale facility to a nine-year life through downstream reuse can result in a net CO2e savings of 24%.

Edge data centres are a great market for this hardware, where performance per dollar is the critical dimension of hardware selection.

Moreover, hyperscalers get the newest technology from vendors much earlier than the broader market, so their ‘end of life’ technology may have been available on the open market for as few as 18 months.

Open hardware standards, such as from the Open Compute Project, now make it possible for solution providers to tailor and certify the decommissioned hyperscale IT hardware for use in other data centres.

This ‘second life’ places IT hardware into the circular economy. By definition, open hardware has the advantages of also letting the solution provider install and update firmware, reconfigure racks, certify the gear for specific software, integrate and test it all, and provide full warranty and support services, rendering the second-life equipment performance-equivalent to new, proprietary equipment. 

A path to carbon neutral and carbon negative

As data centre operators adopt a circular economy model for their edge facilities, they are in a good position to pursue carbon neutral goals – and even strive to go carbon negative. For example, some innovative firms are implementing systems that generate new value from the heat generated by IT equipment.

Typically, waste heat is just that, waste.  But in fact, heat can be leveraged to do productive work and create and capture value from downstream usage. Edge data centres are located near other sectors of the economy that can use that heat productively. This opens up the emerging category of Scope 4 emissions – emissions that can be avoided by the operation of an edge data centre.

Circular economy model improves edge TCO too

The combination of green energy (where possible), a circular economy model and innovative interaction with businesses or residences, provides substantial sustainability opportunities for operators of edge compute and storage.

Fortunately, the combination can drive business efficiencies as well. Circularity models maximise the lifetime of equipment, at the core and at the edge. Edge data centre operators can optimise the upstream supply chain and then continue with the aggressive lifecycle strategies, maximising IT equipment as an asset class as opposed to a waste stream. Leveraging the open hardware platform of OCP creates a backbone of open hardware and software and their cost efficiencies, which also simplify operations management.

By lowering hardware costs, these edge architecture innovations make it easier for data centre operators to expand their operations to wherever they are needed.  IT hardware commonly represents about 75% of the TCO of running traditional data centres. Bringing recertified hyperscale technology the data centre can provide a 50% TCO advantage, and in some edge environments with smaller unique capacities, operators could save even more.

The leading edge of data centre sustainability       

The combined scale of edge computing equipment is forecast to be as much as four times larger than core data centre compute. This is the new frontier of demands for sustainability of infrastructure, and it is our collective opportunity to get it right from the start, rather than replicate dated inefficiencies. 

We must absolutely demand and proliferate renewable energy as broadly as possible.  But this alone is insufficient to curb the negative carbon tax and trajectory of the IT infrastructure we depend on globally.

Recertification and reuse of high-performance, proven hyperscale technology not only catalyses this technical innovation to broader markets, but also stands to accelerate sustainability of the global data centre sector. 

We now have the tools and business models to deliver on this potential, and with their proximity to the very society that sustainability seeks to benefit, edge data centres may start to lead the way.