Seeing Opportunity by Complete Analysis
Water and Transparency
At CyrusOne, transparency is one of our leading values. Since publishing our first Sustainability Report in 2020, we have been committed to leading our industry in the clarity and breadth of our sustainability disclosures. We see reporting as an opportunity to honestly analyze our sustainability programs and report the areas that need improvement along with our successes, providing us with inspiration for future initiatives.
Many data center providers are hesitant to disclose their water use since data centers often consume millions of liters a year. To promote water conservation in our industry, we not only report absolute water consumption but also the water efficiency of both our water-free cooling facilities (the good news) and our few water-consuming cooling facilities (the bad news) so that the average doesn’t obscure where we have work to do.
We then push the envelope further and estimate the water embodied in our electricity supply chain for a full picture of both onsite and offsite regional water impacts. (See the Water section of our latest Sustainability report.)
The standard metric for measuring water efficiency in data centers is Water Usage Effectiveness (WUE). This metric was created by The Green Grid specifically for data centers to understand and compare their water impact on an intensity basis. There are two versions of WUE: WUE Site and WUE Source.
WUE Site is a ratio of liters of annual water use to kilowatt-hours of server energy use, and thus is measured in liters per kilowatt-hour (L/kWh). Because our WUE Site measurements include all water onsite (including water used for domestic use, facility maintenance, and landscape irrigation), even our zero water-cooling facilities have a WUE Site above zero.
WUE Source is an estimation of the total water burden of a facility. This includes water consumed onsite as well as water consumed in the production of the electricity we use, referred to as “energy supply chain water.” WUE Source is a ratio of liters of energy supply chain water plus onsite water usage to kilowatt-hours server energy use, also measured in liters per kilowatt-hour (L/kWh). Energy supply chain water estimates are based on the World Resource Institute’s Guidance for Calculating Water Use Embedded in Purchased Electricity.
Using WUE Source, we have verified the effectiveness of our water-free cooling strategy. As reported in our 2023 Sustainability Report, the average total water burden (WUE Source) of our water-free cooling facilities was 1.89 L/kWh, less than half that of our water consuming facilities (4.42 L/kWh).
