Balancing energy and water in data centres

As we recently marked World Water Day — themed ‘Glacier Preservation’ — it served as a timely reminder that we all have a role to play in tackling climate change and water stress.

But water stress extends far beyond our glaciers. Growing populations, pollution and climate change are amplifying global water challenges, and their impact is increasingly evident in industries not typically associated with natural resources. One such industry is digital infrastructure.

Over the last two decades, data centres have quietly become the backbone of modern society. From enabling telehealth appointments and streaming our favourite content, to hosting the global economy’s digital operations, we have grown reliant on these often-unseen facilities.

To best meet society’s needs, and our collective climate goals, digital infrastructure companies like Equinix must balance the trade-offs between energy and water resources required to operate data centres.

At Equinix, we’ve been working proactively to address the challenge of responsible resource management. Balancing our use of energy and water resources is essential to embed sustainability into the digital economy.

Why do data centres use water?

Data centres generate a lot of heat. With rows upon rows of servers running 24/7, efficient cooling systems are essential to prevent costly and potentially catastrophic overheating.

In a nutshell, servers produce heat; that heat is then transferred from the server room to the building-level cooling system via a heat exchanger. The building-level cooling system then removes the heat from the building by rejecting it to the outside air.

One of the most energy-efficient cooling methods is evaporative cooling, which leverages the natural process of evaporation to remove heat and maintain safe temperatures. However, this method also consumes water, which can strain resources in regions already experiencing water stress.

Balancing energy and water consumption presents a fundamental trade-off: while evaporative cooling can reduce energy consumption and the associated carbon footprint, it comes at the cost of increased water use. On the other hand, air-cooling methods do not use water, but require more energy than evaporative cooling.

Data centre cooling system. Image supplied.

Responsible water use

At Equinix, we take our role as environmental stewards seriously. We have developed a global sustainability strategy that embeds water-conscious decision-making into every stage of a data centre’s life cycle, from site selection to operations.

Some of our key initiatives include:

• Transparency and reporting: In 2024, Equinix earned a B score in CDP’s Water Questionnaire (formerly Carbon Disclosure Project), reflecting the company’s commitment to transparency by tracking and publicly reporting water usage across our sites.
• Industry standards and metrics: Equinix has contributed to the development of key water efficiency standards, including the ISO/IEC 30134-9 Water Usage Effectiveness (WUE) metric. This metric helps us and other operators measure water efficiency in cooling systems while balancing it against power usage effectiveness (PUE), which tracks energy efficiency.

Climate-tailored design

With a network of more than 260 data centres around the world, no two regions face the same water accessibility challenges. As such, Equinix assesses new data centre locations methodically, ensuring water stress is a key consideration in the site selection process.

For example:

• In water-stressed areas like parts of Spain, Equinix have opted for air- or chiller-based cooling systems, consciously avoiding evaporative cooling to avoid strain on local supplies.
• Where climate conditions allow, the company looks to harness free cooling, which leverages naturally cooler outside air to support our cooling needs, thereby reducing our reliance on mechanical cooling systems when conditions allow.
• In locations such as Amsterdam and Toronto, we leverage unique geothermal opportunities like deep cold lake water and aquifer thermal energy storage to reduce our environmental impact.
   

Unlike energy, using water to cool a data centre is a choice, not a requirement. While all data centres require energy, the decision to use water or not is a decision we make intentionally based on the local climate and long-term sustainability of available water sources.

Innovative cooling technology

Looking ahead, innovation will play a critical role in reconciling the dual challenges of optimising energy and water usage.

One aspect of innovation is evaluating alternative water sources to decrease data centre demand on potable water — that is, water that could otherwise be used for human consumption. Taking advantage of alternative water sources like reclaimed water and desalinated water can help with that, where opportunities exist. In 2023, 25% of the water used in Equinix’s evaporative cooling systems came from non-potable water sources, most of which was reclaimed water.

One of the most promising server cooling solutions is closed-loop liquid cooling. Unlike traditional evaporative cooling, these systems circulate a mixture of liquids (including water) through a sealed mechanism, avoiding water loss via evaporation.

This approach enhances cooling efficiency, making it particularly suitable for high-performance workloads, such as those generated by machine learning and AI technologies.

At present, more than 100 of our data centres are exploring these solutions, with some adopting ‘direct-to-chip’ liquid cooling to improve processor temperatures while minimising overall resource consumption.

Why this matters

The stakes for responsible water usage in the technology industry extend beyond optics or regulatory compliance.

Water is a finite and invaluable resource, essential for communities, ecosystems and industries alike. Its availability determines the health and resilience of millions of people, while sustaining the natural processes our planet relies upon.

At the same time, digital infrastructure is indispensable to modern life. From the rapid expansion of AI to the everyday reliance on cloud platforms, we cannot afford inefficiencies in data centre operations. Like it or not, the digital and natural worlds are deeply interlinked.

This presents an opportunity, and a responsibility, for the data centre industry to prove that digital progress and environmental sustainability can co-exist harmoniously.

A sustainable digital future

At Equinix, we withdrew around 6000 megalitres of water globally in 2023, roughly equivalent to the annual usage of 33,900 AU homes. While this total may seem sizeable, context matters.

Only 40% of our data centres rely on evaporative cooling, and nearly 25% of the water we withdrew for cooling in 2023 came from non-potable, reclaimed sources.

Still, we believe there is always room for improvement through embedding cooling solutions, collaborating on industry-wide standards and continually disclosing our metrics.

We are committed to enhancing resource efficiency while maintaining strong performance.

Balancing water usage with energy efficiency is not just an operational challenge; it’s a moral imperative. With increasing stakeholder scrutiny, this commitment will only become more critical in the years ahead.

As World Water Day reminds us, water is a resource that sustains ecosystems, economies and entire communities. Just as we rely on digital infrastructure to power our world, we must also ensure that our operations support a healthy balance across a variety of the planet’s most precious resources.

At Equinix, we believe that technology and sustainability go hand in hand. By taking bold action today, we are not only ensuring the resilience of the digital economy, but also helping to preserve the world’s water supplies for generations to come.

Because when it comes to safeguarding the future, whether in data centres or natural ecosystems, every kilowatt and every drop of water counts.

Top image credit: iStock.com/gorodenkoff