As our dependence on cloud-based services continues to grow, one often overlooked consequence is the enormous water consumption required to keep data centres running efficiently. These facilities, which power everything from streaming services to online banking, are the backbone of the digital world we live in. However, the water needed to cool the servers inside these centres is reaching crisis levels, and it’s starting to affect communities worldwide.
The Scale of Data Centres and Their Water Usage
Data centres house thousands of servers that store and process the data we rely on daily. Google’s facilities support services like Gmail and YouTube, while Microsoft’s Azure network powers a wide range of cloud services. Even simple applications like weather forecasts or GPS navigation depend on the smooth operation of these centres. The scale of operations is vast, with major companies like Google, Microsoft, and Amazon operating hundreds of data centres across the globe. Google alone runs data centres in 24 regions, while Amazon Web Services (AWS) manages facilities across 26 regions worldwide.
The challenge for these data centres lies in cooling. Servers generate immense heat, which needs to be dissipated to prevent system failure and damage to expensive hardware. Cooling is essential, but it’s also resource-intensive, with two primary cooling methods used: air cooling and water cooling. While air-based systems are common, water cooling is significantly more effective, making it the preferred method for many large-scale data centre operators.
Why Water is Essential for Cooling
To prevent overheating, data centres rely on cooling systems that use large amounts of water. For example, a 1-megawatt data centre can consume up to 25.5 million litres of water annually just to manage the heat generated by its servers. Larger facilities, such as those operated by Google and Microsoft, consume water in the millions of gallons every day. Google’s data centres use approximately 550,000 gallons (2.1 million litres) of water daily, which adds up to around 200 million gallons (760 million litres) per year per facility.
The cooling process involves multiple stages, including the use of chillers and cooling towers, where heated water evaporates into the air, losing a significant amount of water in the process. AWS employs direct evaporative cooling, where water is used to cool air entering server rooms, which again leads to substantial water consumption. In fact, AWS has a global Water Usage Effectiveness (WUE) metric of 0.19 litres per kilowatt-hour, illustrating just how much water is needed to support cloud computing.
The AI Water Crisis
The rise of artificial intelligence (AI) has only intensified the demand for water in data centres. AI models, particularly those used in machine learning, require enormous computational power to process complex tasks. As AI applications become more widespread, particularly with the use of large-scale models like GPT-3, the water required to cool the systems that power these applications is growing exponentially. In fact, GPT-3 alone consumes an estimated 500ml of water per 10-50 queries. Multiply this across billions of users, and the total water footprint becomes staggering.
By 2027, the demand for water driven by AI is projected to account for up to 1.7 trillion gallons of water annually, a figure that far exceeds the total water consumption of countries like Denmark.
Where Data Centres Source Their Water
Data centres primarily source water from municipal supplies, often using potable water, which is treated and suitable for drinking. However, some companies are beginning to use alternative water sources, such as reclaimed water or groundwater. Google, for example, sources over 25% of its water from non-potable sources. Still, these alternative sources are limited, as they often face regulatory restrictions or high treatment costs.
Efforts to reuse water within cooling systems have been made, with some companies reducing water usage by up to 50% through closed-loop systems. However, challenges such as mineral buildup and contamination often make water reuse difficult at scale, requiring new investments in treatment infrastructure.
The Controversy
The growing water consumption of data centres is causing significant concern in water-stressed regions. By 2025, half of the global population is expected to live in areas facing water scarcity. This has already led to protests, such as the opposition to a large data centre project in Uruguay, where local communities feared further depletion of their water supplies. Similar issues have surfaced in other regions, including the Netherlands and Chile, where data centre developments have clashed with the need for local water resources.
The competition for water also has socio-economic consequences. When data centres consume vast amounts of water, it often comes at the expense of agriculture, as farmers find it harder to access water for irrigation. This can lead to reduced crop yields and rising water prices for residents.
The Path Forward
In response to the growing environmental concerns surrounding water usage, major tech companies have begun committing to more sustainable practices. Amazon, Microsoft, Google, and Meta have all pledged to become “water positive” by 2030, meaning they will replenish more water than they consume. For instance, Amazon aims to restore 3.9 billion litres of water annually through conservation projects, while Microsoft has committed to reducing water usage in its evaporative-cooled data centres by 95% by 2024.
Additionally, companies are exploring circular water solutions, such as closed-loop cooling systems and water restoration projects, to mitigate their environmental impact. These solutions not only aim to reduce water consumption but also ensure that data centres can continue to operate in a sustainable way, without further straining local resources.
Conclusion
While data centres are integral to the digital world we rely on, their environmental footprint – particularly in terms of water usage – is increasingly under scrutiny. As demand for cloud services and AI grows, so too does the pressure on water resources in areas already facing shortages. The tech industry’s response will be critical in determining whether it can continue to operate without exacerbating the global water crisis. With large companies pledging to become water-positive, there is hope that data centres can transition to more sustainable practices, but it will require significant investment and innovation to address this hidden cost of the cloud.
