Sustainable Water Use in Data Centres

By David Watkins, solutions director at VIRTUS Data Centres.

Data centres are the linchpin of digital transformation. These critical facilities house the servers and infrastructure that power our favourite online services such as streaming, online banking, podcasts, maps, and much more. But their continued growth and usage, fuelled by applications such as artificial intelligence (AI), needs to be managed both economically and sustainably.

The rapid proliferation of data centres has led to many critical questions being asked about their environmental impact, not least concerning water usage in cooling technologies.

Acknowledging the environmental effect of their operations, data centre operators have already taken important steps to address sustainability concerns; ambitious targets have been set as testament to the industry's commitment to reducing its ecological footprint. These targets encompass various facets of sustainability, but a central focus is on minimising water consumption.

Cooling: the Environmental Cost

When it comes to keeping the digital infrastructure working, data centres need cooling technologies to keep the IT equipment housed within them at the optimum temperature and humidity so that they run as efficiently as possible. This makes cooling technology critical, not only to maintain the best environment for the IT systems, but also to consume power responsibly. Data centre cooling systems include cooling towers, chillers, pumps, piping, heat exchangers / condensers and computer room air conditioner (CRAC) units. Data centres also need water for their humidification systems and facility maintenance.

Traditionally, data centre air conditioning equipment is either water or air cooled. According to research carried out by Savills, it is considered that a data centre could use up to 26 million litres of water each year, on average, per megawatt of data centre

power. Although this appears to be an alarming statistic, unnecessary water leakage by water companies themselves is also a major cause for concern. According to OFWAT, in 2020-21 England and Wales leaked 51 litres of water per person per day, and in Scotland and Northern Ireland this figure was above 80 litres of water.

However, it should be recognised that many data centres use ‘closed loop’ chilled water systems - meaning that water is charged into the system during construction and then continually circulated within a facility, rather than needing new water consistently pumped into the building. A large-scale data centre will be filled with around 360,000 litres of water initially, or the equivalent of a 25 metre local swimming pool. This water will remain in the system for the lifespan of the data centre, typically a minimum of 15 years.

The Need for Continuous Innovation

Water usage concerns leave data centre operators grappling with a dual challenge. On one hand, they must meet the ever-increasing demand for data processing requirements, and on the other they must navigate the intensifying effects of climate change. Compounding the situation, with each passing summer temperature peaks are becoming more severe. For example, research by the UK government finds that the country is experiencing rising temperatures which effects the availability of water; the most recent decade (2012 to 2021) has been on average 1.0°C warmer than the 1961 to 1990 average; all 10 of the warmest years in the UK have occurred since 2003; 2022 was the UK’s hottest year on record, with an average year-round temperature above 10°C seen for the first time. This trend creates an ever-increasing need for innovative approaches to data centre cooling.

The data centre industry has long been committed to ensuring sustainability and efficiency, with providers working hard to use resources including power and water responsibly. In response to these challenges, data centre operators are embracing innovation as a cornerstone of their sustainability efforts. Indeed, companies in the sector are continually looking to innovative sustainability strategies that include things like alternative and renewable sources of power, rainwater harvesting, zero water cooling systems, recycling, waste management and much more.

One great example is the strategic re-evaluation of cooling equipment led by organisations like VIRTUS. By altering the point in the cooling cycle at which water is introduced, operators can make substantial reductions in water consumption. Implementing this practice, along with other efficiency initiatives can save up to 55% of water consumption, and also reduce the use of related consumables such as water filters and associated maintenance.

This is showcased at the LONDON2 data centre in Hayes, London. The mission is twofold: to enhance electrical efficiency and optimise water usage, driven by the recognition of the pivotal role data centres play in minimising their environmental impact wherever possible.

In the UK, where ambient conditions provide the ideal backdrop, VIRTUS had already harnessed adiabatic cooling technology to cool the data halls efficiently. Leveraging the day / night cycle, free cooling was implemented to maintain the desired temperature within the facility.

What makes LONDON2 exceptional is its strategic location above a natural aquifer, enabling the use of water that is not drawn from the public supply - another example of its commitment to responsible resource management by design.

These kinds of innovative approaches help to ensure that water usage is minimised precisely when it matters most - during periods of the highest outside temperatures.

Collaborative Responsibility

The data centre industry has made a great deal of progress in terms of developing and implementing innovative cooling solutions which have the potential to reduce its environmental impact. The right cooling solutions are crucial to helping providers meet their green ambitions and positively affect customer Environmental, Social and Governance (ESG) targets.

It’s important to note, that achieving sustainable data centres is a goal that cannot be reached in isolation. It necessitates industry-wide collaboration and knowledge-sharing to make real change possible. Data centre operators are already coming together to share best practices, techniques, and insights, with a particular focus on water-saving strategies. This collaborative approach magnifies the impact of sustainability initiatives and accelerates progress toward shared environmental objectives.

The collective responsibility of the data centre industry to reduce its environmental impact is an inspiring model for other sectors to look to for best practice. As data centre operators unite in their commitment to sustainability, they set a powerful precedent for industries worldwide. They demonstrate that sustainability is not just a buzzword but a tangible goal that can be achieved through creativity, innovation, and concerted effort.

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