How to manage data center water usage sustainably

How much water data centers use

According to The World Counts, an open source community-driven project that aggregates consumption data from organizations around the world, more than 4.3 trillion cubic meters (approximately 1.1 quadrillion gallons) of water are consumed globally every year. Tech giants, like Google, Amazon and Microsoft, release their water consumption figures to the public.

Google

In 2022, Google shared its commitment to climate-conscious data center cooling with the release of its water consumption statistics from the prior year. In 2021, Google's data centers consumed approximately 4.3 billion gallons of water. On average, a Google data center consumes 450,000 gallons of water a day.

Amazon

While Amazon does not disclose its total water consumption, a public report stated that AWS data centers use 0.19 liters (L) of water per kilowatt-hour (kWh). For context, the average data center uses 1.8 L of water per kWh. This metric is known as water usage effectiveness (WUE), a term developed by The Green Grid that measures data center sustainability in terms of water usage and its relation to energy consumption. WUE is a ratio of the consumption of water in liters and the consumption of energy in kilowatt-hours. The lower the ratio, the more efficient it is.

Microsoft

Microsoft published both its annual water consumption and its WUE. In total, Microsoft's consumption was nearly 1.7 billion gallons of water in 2022. According to Microsoft, the company's data centers globally use 0.49 L of water per kWh.

Other data centers consume water on a massive scale and do not publish or collect the requisite data to provide an accurate picture of how much water data centers consume globally by the industry. Admins of data centers must recognize the importance of transparency and share their water consumption figures. This will create a baseline for the industry and form new sustainability goals to ensure the industry is doing its part to reduce water consumption, limit climate change and protect water availability.

Ways data centers use water

The major areas of consumption come down to cooling and humidification systems.

Cooling systems

Data centers have highly sensitive, power-intensive IT equipment, much of which is constantly up and running. If equipment gets too hot, it can overheat, malfunction and break down. To maintain uptime and avoid equipment failure, many data centers use water-based cooling to help equipment remain at safe temperatures.

According to an article in npj Clean Water, there are several mechanisms for data center cooling. These mechanisms include chillers that reduce air temperature by cooling water and use it as a heat transfer mechanism; cooling towers that reroute hot air across a wet media to evaporate the water; and adiabatic economizers that spray water into the airflow or onto a heat exchange surface to cool air that enters the data center. While some of these systems recirculate water, water loss is inevitable due to evaporation and to maintain water quality.

Humidification systems

Drier air creates static electricity buildup that can lead to electrostatic discharges. This is dangerous for the sensitive equipment in a data center. To reduce this buildup, many data centers use humidification systems to maintain a target humidity level. These systems can vaporize water and add it to the air or draw in air to remove moisture.

Data centers also use water indirectly through electricity. Power must come from somewhere, whether by burning coal or through hydropower plants. That electricity generation consumes water.

How to reduce data center water consumption and use water more sustainably

Here are a few ways data centers can limit water consumption:

• Collect and analyze water usage data. Establish WUE as a necessary metric to track. Gather data on total water consumption, which includes direct and indirect consumption. This reveals water use.
• Find ways to reuse water. Some cooling systems can recirculate water to avoid waste. Set up a system to harvest rainwater and gray water or recycle water to local communities.
• Experiment with new water management techniques. It may prove effective to transition away from traditional cooling and toward targeted cooling that focuses on individual rows of servers. Experiment to find new and more efficient water management techniques. Google, for instance, applies AI and machine learning to train deep neural networks in the data center to help optimize water metering, monitoring and management.
• Replace legacy systems. Modern cooling systems and technologies are more efficient. Assess older equipment, and upgrade to more sustainable infrastructure.
• Build new facilities in colder climates. Geography plays a big role in data center sustainability. Data centers built in hotter, drier climates strain local water supply and require more intensive cooling. Data centers built in colder climates can use the cold air from the external environment to maintain equipment temperatures.
• Ensure no coolant waste. Carefully search for and properly seal and caulk any openings in the facility to ensure no coolant waste. This helps maximize cooling efficiency.
• Use cooling methods other than water. There are other ways to keep data center equipment cool. Organizations are working to provide more environmentally friendly ways to cool data centers. Novenco uses industrial fans that work with the outside air to cool data centers. Although this does not completely stop water usage, it greatly reduces it.
• Explore alternative sources of water. Many data centers pull from local water reservoirs using potable water. Instead, transition to alternative and more sustainable sources of water where possible. For example, Google's data center in Hamina, Finland, has found a way to use nonpotable seawater to cool equipment.
• Participate in water replenishment programs. Some organizations, like Microsoft, partner with local communities to invest in projects to replenish water back into the basins that need it most. This can help protect and extend water availability.

Given the state of the climate crisis, there's a need for all data centers to curb their water consumption and build more sustainable infrastructure, also known as green data centers. Doing so is necessary to achieve global sustainability goals that help prevent the worst effects of climate change.

Jacob Roundy is a freelance writer and editor, specializing in a variety of technology topics, including data centers and sustainability.