Not All Water is Created Equal, Especially in the Data Center Industry
It’s an unfortunate truth that typical data centers use a lot of water. In fact, researchers at the Texas Tech University Water Resource Center tout that data centers can use between three and five million gallons of water per day, the same amount of water used by a city of 30,000 to 50,000 people.
In most data centers, water is commonly used for cooling purposes to replace the use of electricity or other energy sources. Water provides a clear benefit to data center companies—it’s cheaper than electricity and is considered free of carbon emissions compared to electricity from electrical grids that still rely on fossil fuels. This is why many data centers keep equipment cool with evaporative cooling technologies, which evaporate water to reject heat from the data center.
Stressed Out Water
However, at CyrusOne, we recognize that water is a limited resource in high demand. The “positives” to water use don’t take into account the fact that many regions around the world, including in the US and the Europe where we operate, face increasing demand and dwindling supplies of fresh water. Intense water use and drought—one of the commonly predicted consequences of climate change—are causing many regions to experience increased water stress.
Water stress—a shortage of fresh water resources to meet regional water demand, otherwise known as water scarcity—is not just a current issue. Researchers at The World Resources Institute predict that regional water stress will continue to worsen over time, with more regions and watersheds facing extremely high water stress within just 10 to 20 years (well within the lifespan of our facilities).
Increased water stress in areas where CyrusOne operates is an issue for local communities and a potential threat to our operations. Facilities dependent on water for cooling and located in regions under high water stress are at risk of operational interruptions due to water shortages and friction with local communities in competition over dwindling local water supplies. This means, as a company, it’s important to assess and improve how our facilities use water in high water stress regions to ensure a good relationship with local communities, conserve local watershed health, and maintain proper cooling of our customers’ equipment.
Water Coming and Going
At CyrusOne, we think about our water use in terms of withdrawal, discharge, and consumption.
Water withdrawal is the total water taken in by a facility (“withdrawn from the watershed”). All of our facilities withdraw water from municipal supply (except for our Hamilton, Ohio geothermal cooling system which draws groundwater). If we can’t withdraw enough water to support our operations, then we need to change the way we operate (whether in cooling, landscaping, or facility maintenance) – thus withdrawal is the impact of regional water stress on our operations.
Once in our facilities, water is either used for non-evaporative processes (facility maintenance, domestic water, etc.) and discharged to water treatment works or consumed through evaporative cooling or irrigation. Facilities that utilize water-consumption-free cooling (“water-free cooling”) do not evaporate much water, meaning that water withdrawn is mostly returned to the watershed when it is discharged to water treatment works.
Water consumption is the portion of water withdrawn by the facility that is not returned to the watershed. Since the consumption of water in irrigation and evaporative cooling removes it from the watershed, this means that consumption is the impact of our facilities on regional water stress.
Water withdrawal is the impact of regional water stress on our operations.
Water consumption is the impact of our facilities on regional water stress.
Some data centers have turned to using recycled water at their facilities to reduce their use of potable water. However, how this affects regional water stress requires a closer look. While using recycled water in data center cooling may provide a second life to used water and save energy for water treatment, it may not actually help with water stress. If the recycled water would have re-entered the watershed as recharge, then evaporating it still contributes to water stress. In coastal areas, if recycled water would have been discharged to the ocean (and lost to the watershed), then cooling with recycled does provide a benefit to water stress.
Reducing Total Water Use
Most of our facilities already use water-free cooling systems, which utilize air-cooled chiller technology to cool a closed loop of water. The closed loop piping is only filled with water once and is circulated to keep a facility cool without any consumption. We continue to update our cooling systems at existing facilities to reduce our water consumption, especially in high water stress regions.
While most of our facilities use water-free cooling, we don’t simply want to do “less bad”, we want to do “more good” and leave regions, especially those under water stress, better than if we were never there. With climate change intensifying and water stress levels are predicted to increase across the world, we believe that all companies should be working toward water-free cooling and net positive water facilities. Read about our net positive water methodology in our next blog post.