Innovations & Strategies for Sustainable Data Centres

With the UK attempting to accelerate towards a hyper-connected future, the environmental cost is becoming increasingly clear. One of the most pressing - and often overlooked - challenges is the growing water consumption of data centres.

These facilities, which power everything from AI to cloud computing, rely heavily on water to cool high-performance IT equipment. With reports of UK data centres estimated to use close to 10 billion litres of water annually, there's no doubt that serious concerns are being raised, especially in regions already facing water stress. 

With more than 477 data centres currently operating in the UK, and many more planned, the pressure on local resources is mounting. This blog takes a look into potential options which will enable us to rethink how we manage water in the digital age. 

Data Centre Cooling Methodologies

As we’ve indicated, the projected growth in data centre developments across the country will inevitably intensify the demands we place on our existing water resources.

Simply put, the only way to avert a water shortage crisis is through innovation, and these innovations are already underway:

• Smarter Cooling Technologies:  less water-intensive cooling methods such as direct-to-chip cooling, and advanced free cooling (using ambient air more efficiently) are being developed.
  
  
• Water Recycling and Reuse: closed-loop cooling systems are being adopted that can significantly reduce a facility’s reliance on potable water.
  
  
• Optimising AI Workloads: more efficient GPU chips and AI models can help lower energy and water demands.

The cooling methodologies chosen by data centres reflects factors such as surrounding climate, energy efficiency targets, and clients’ requirements. 

Some of the more common strategies employed by data centres include:

• Free cooling, which uses convection to remove heat from the medium to be cooled (usually a water-glycol mixture) via the ambient air. The free cooler is installed outdoors and might contain a lamellar heat exchanger - or something comparable - through which the warmed water-glycol flows to remove the heat. The larger the contact surface of the lamellae, the more efficient the system. Air flow can be increased using fans, thus boosting the cooling output while expending minimal energy consumption for cooling.

• Direct free cooling uses the cooling medium as directly as possible to remove the heat generated by the data centre. For example, large data centre operators with uniform environments use the outside air - they literally blow outside air directly into the data centre.   A good example is the Yahoo self-cooling data centre in New York State, near the border with Canada.  Cold air flows into the building via slats in the side walls, while the warm air is dissipated via the roof. Ideally, the only additional energy this solution requires is using fans to help with moving the air.
  
  Any form of free cooling requires the use of up-to-date weather data to calculate the temperatures at relevant sites, and while the UK's temperate climate allows for greater use of free cooling for a significant portion of the year, warmer summers and the increasing density of IT equipment is necessitating more robust cooling solutions. Chief among these are cooling systems that use water - based on the fact that water conducts heat up to 4,000 times better than air.

• Adiabatic cooling, for example, is a complementary technology which improves the efficiency of direct free cooling.  Before intake air reaches the heat exchanger, water is sprayed into it. The water droplets evaporate immediately and this transition from liquid to gaseous state results in the water extracting heat from the surrounding air.  Modern adiabatic systems are designed to minimise their water use, varying consumption based on ambient conditions.

• Closed-Loop Chilled Water Systems meanwhile are a popular choice for UK data centres where water is circulated within the facility and cooled by chillers.  While the stored water volume can be substantial, this water is largely recycled.  That said, these systems still require periodic top-ups due to minor leaks or maintenance and the chillers may use some water for their own cooling.

• “On-Chip” directs cooling inside servers to small heat sinks which are attached to chips and other important hardware within. This method uses air as the medium for removing heat.  However, as we’ve indicated, processing power continues to climb and miniaturisation is still the focus.  Liquid On-Chip increases the efficacy of this method and continues to push the limits of cooling within increasingly smaller footprints.

• Full Immersion Cooling takes things to the next level.  Instead of passing liquid by the heatsink to wick away excess heat, the whole server is placed into a reservoir of ‘thermally conductive dielectric coolant’ which comes into to contact with the equipment from all angles allowing maximum removal of waste heat.  Combining this with other methods of cooling is a big positive as Full Immersion can operate at higher water temperatures than other techniques.  And it’s possible to use the waste heat to warm offices, raising the efficiency levels up further.
  
  

Towards a More Strategic Future

Future data centre developments need to include water resource demand assessments as a critical factor in submitting planning applications. 

This includes local water availability and any projected water stresses, together with an assessment of the ability of the existing infrastructure to support the facility.

As we indicated in the introduction, it shouldn’t be forgotten that along with direct use, data centres also have a substantial indirect water footprint linked to their electricity consumption. Power generation, particularly from thermal power plants (coal, gas, nuclear), is a water-intensive process, requiring water for cooling turbines and other equipment.

The UK government needs to mandate comprehensive and standardised reporting of water abstraction and consumption for all data centres, as is the case for energy reporting.  The aim is to ensure data is available for informed policy-making and public scrutiny.

Meanwhile, LPAs need to rigorously assess the water impact of new data centre applications, with clear guidelines for rejecting developments in highly water-stressed areas unless robust, sustainable water solutions are guaranteed.

There is also a need for greater collaboration between government bodies (Defra, Environment Agency, Ofwat), water companies, industry trade associations, and data centre operators to share best practices and develop industry standards for water resource management.

A Sustainable Digital Future

While laudable, the UK's ambition to be a global leader in the digital economy and AI must be pursued with proactive management of its environmental consequences.

The growing water consumption of data centres represents a significant challenge, particularly with the country facing increasing water stress. Local communities should not be disadvantaged for basic service provision because they have a new data centre built in their midst.

However daunting this challenge, it could also be an opportunity for the UK to demonstrate innovation and leadership to the world.

By embracing cutting-edge cooling technologies, implementing comprehensive water recycling and reuse strategies, being more considered about site selection, and establishing clear regulatory frameworks, the UK can set a global benchmark for sustainable data centre operations.

This integrated approach will not only mitigate environmental risks but also enhance the long-term resilience and social license to operate for the digital infrastructure that underpins our modern lives.

FAQs

What are the most sustainable cooling solutions for data centres?

Sustainable cooling methods include closed-loop and adiabatic systems that recycle water and direct-to-chip cooling that reduces wastage.

Many operators are also using AI analytics to monitor water use in real time and detect inefficiencies before they become costly leaks or environmental risks