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Decarbonising datacentres: Turning the hot air about heat reuse into real-life use cases

Reusing waste heat from datacentres to warm local businesses and homes could bring about considerable reductions in carbon emissions and lower energy costs, so what needs to happen to make this a more widespread practice?

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The UK was the first nation to set a legal commitment for net-zero carbon emissions in 2019. This requires tackling hard-to-abate sectors while ensuring that day-to-day functions are not disrupted.

The internet provides many services for a large part of our lives and this has increased massively as a result of the Covid-19 pandemic, as social distancing requirements resulted in a marked rise in remote working and video calls.

At the same time, the use of cloud-based applications and backup and streaming services soared, while healthcare organisations quickly pivoted towards using video appointments to minimise in-person interactions.

Now, life moving forward is likely to remain highly dependent on the internet and the datacentres working behind the scenes to power these example use case.

The significance of datacentres in our everyday lives is reflected in the electrical energy demand of the sector. Published estimates and industry growth trends suggest energy use to be between 2% and 4% of the UK total.

In other countries, it is much more. For example, in Ireland, datacentre energy use is reported to be as much as 15% of total use and projected to double in the next five years.

Also, datacentre energy use is expected to increase globally as we continue to take advantage of digitisation and big data opportunities. Another factor driving future growth in datacentre energy use is the increasing dependence of the internet on the ever-expanding number of satellites orbiting the Earth.

This involves the development of partnerships between cloud providers and satellite operators, and the previously autonomous ground stations are likely to be implemented as part of the edge in the future.

Operators invited to help bolster UK’s datacentre heat reuse efforts

London South Bank University (LSBU) is seeking participants from the datacentre industry to get involved with its study into how server farm waste heat can be reused in a cost-effective way to help operators improve their efficiency and reduce their site’s carbon emissions.

The university is asking members of the UK datacentre community to fill out an anonymous survey, which will expand its understanding of the range of datacentres present in the UK today.

Its results will also help to establish best practice for capturing waste heat from datacentres, and will provide researchers with some insight into how much heat energy is potentially available for recovery from the sector.

Participants will be offered a free evaluation of waste heat recovery potential for their datacentre, and will also be given the opportunity to benchmark their own datacentre’s performance against anonymised responses from their competitors.

To explore the recovery of waste heat energy from your datacentre, use this link to participate in the LSBU study or contact Matt Wegner at [email protected]

The datacentre sector is conscious of its environmental footprint and there is a noticeable push towards securing renewable energy for the industry, whether by power purchase agreements with energy suppliers or by on-site generation, and efficiency is already embedded at the core of most facilities.

All of the electrical energy used by a datacentre is eventually converted into heat, which is typically discharged into the atmosphere using refrigeration equipment that is extremely costly to operate and maintain.

This heat is often considered to be an unwanted by-product of datacentre operations, but opportunities exist to contribute to minimising emissions from datacentres in the future through proactive reuse of it.

The UK government, for example, made reference to datacentres being a prime source of waste heat that could be repurposed to warm homes and businesses in its net-zero strategy document, published in October 2021.

The document details how the UK government intends to achieve its goal of reducing greenhouse gas emissions to net-zero by 2050 through a range of measures, including finding ways to reuse the waste heat generated in commercial and industrial processes.

The reason for this is that it is hoped that doing so will help decarbonise the UK’s heating and cooling sector, which is reportedly responsible for about 50% of energy use and 33% of overall carbon emissions.

Overcoming the barriers to widescale heat reuse

As with any new technology, there are a number of challenges that need to be overcome first to take full advantage of the opportunity and promise of heat reuse.

One of them is the proximity to the heat demand. For example, the closer a datacentre is to homes or businesses in need of heat, the better. This could be achieved with government support and policy-making in the UK, as many European Union member countries have already done.

Where datacentres cannot be situated near existing heat demand, applications such as greenhouses or sustainable farms could be purposely located there to make use of this low-carbon, low-cost energy, which is a path Norwegian colocation firm Green Mountain is pursuing.

The captured heat also has to have a price in order to secure the return on investment, and to let the competition drive the change.

There are a number of facilities around the world already demonstrating the feasibility of installation, environmental benefits and enormous savings resulting from recovering waste heat.

These include Amazon’s partnership reusing the waste heat from the neighbouring Westin Building Exchange at its Seattle headquarters and Facebook’s newly constructed WHR system at its Odense datacentre, which feeds the warm water from its cooling system to the town’s district heating system, similar to the case of Yandex DC in Mäntsälä, Finland.

Using waste heat to improve datacentre energy-efficiency

In urban areas, waste heat can be captured from datacentres and then distributed at point of use to deliver hot water and space heating. There is a drive towards the installation of edge facilities, which comprise smaller, distributed datacentres on the outskirts of urban areas, close to potential heat demand.

Also, chip and rack densities are growing in line with workloads and the need to cut future emissions is likely to drive increasing interest towards developing more efficient, liquid-cooling approaches, which will result in higher temperatures for the available secondary heat.

Utilising the waste heat would greatly reduce the carbon footprint of datacentre operations overnight and, in so doing, make a significant contribution to the UK’s journey to net-zero.

This topic is the subject of an investigation at London South Bank University (LSBU) to explore opportunities, identify challenges and understand the benefits of datacentre waste heat recovery, both for the datacentre itself and for the UK as a whole.

“This project brings together engineering disciplines in a smart way to share resources and minimise emissions and shows the nature of real-world research that goes on in the School of Engineering at LSBU,” says Asa Barber, the university’s dean of engineering.

The need for continuous operation and observing strict temperature control requirements typically make datacentres an excellent candidate for participation in heat networks.

Air-cooled datacentres, which currently dominate the market, can be incorporated into low-temperature heat networks.

One approach for integrating a datacentre into a low-temperature heat network is demonstrated by the GreenSCIES project, which aims to deliver an easily replicable blueprint for a smart local energy network in any urban area.

The detailed design delivered by this project will provide an ultra-low-temperature 5th generation (5G) heat network with distributed low-carbon heat pumps to supply heating/cooling.

It does this by using ambient loop to exchange energy between buildings to recover waste heat from datacentres and London Underground ventilation air.

The waste heat captured by the network is then distributed to its planned point of use and can be upgraded to a higher temperature by a heat pump located in a decentralised energy centre.

This provides (low-carbon) heat at the temperature needed, which can be delivered virtually emission-free.

The energy centres will be supplied with electricity from solar photovoltaic panels, which will also charge electric vehicles enabled with vehicle-to-grid charging/storage alongside large-scale batteries.

Datacentre World debate: Hear more about heat reuse

Matt Wegner will be participating in a panel debate at Datacentre World 2022 at Excel on Wednesday 2 March on the topic of opportunities and blocks for waste heat utilisation. The debate takes place in the Data Centre Design and Build & Physical Security Theatre at 1.30pm.

“GreenSCIES provides a real-life example of how energy can be recovered and reused in a much more sustainable way,” says Catarina Marques, GreenSCIES project manager at the LSBU.

Combining heat, power and mobility in one place creates synergies with ultra-low emissions and at an attractive cost for the consumer. It also provides the opportunity for the community to own and operate its own local energy system.

It is hoped GreenSCIES will be the first large smart energy system in the UK that integrates energy technologies across heat, power and transport, providing a model for wide-scale replication.

The GreenSCIES system does not necessarily need to involve a datacentre – there are many other potential sources of heat that can be used. However, datacentres are often situated in the right place (urban areas), close to regions of high-density heat demand, and have good characteristics for use in this type of application, including steady temperatures and having a continuous need for cooling.

As of 2018, there were probably just under 500 large datacentres in the UK, together consuming between 11TWh and 42TWh of electrical energy. From a heat generation standpoint, this corresponds to the equivalent of 2.5-10% of the nation’s domestic heat demand, according to data from energy regulator Ofgem.

Therefore, the benefits to residents and businesses in communities where datacentres are present could be huge if that energy is reused, which is why the LSBU launched its investigation into how much heat energy is potentially available to be used, rather than wasted.

Read more about datacentre heat reuse projects

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