Data-Driven Water Savings
By Namrita Kapur, Director of Strategy, EDF Business November 2012 - Facilities Management
Affecting more than half the country, this summer’s drought has put water issues front of mind. As the risk to supply chains and communities where they operate increase, not surprisingly, companies are paying more attention to their water impact.
Notably, this summer Facebook was the first company to ever release water usage effectiveness (WUE) data. WUE is a metric released in 2011 by GreenGrid, which builds upon the success of GreenGrid’s power usage efficiency (PUE) metric, now ubiquitously employed across data centers. As the term suggests, WUE gauges the efficiency of water use in data centers.
Water use? Why does a data center use water? Well, the transfer and storage of data generates a great deal of heat, which needs to be removed for the equipment to continue to function smoothly. That heat removal usually occurs through the use of a water cooling tower, which uses significant amounts of water. Building cooling, in general constitutes 60 percent of water use in buildings. Because of the higher intensity of heat generated, data centers use an average of 20 percent more water for cooling than other types of buildings.
In August, Facebook reported that the WUE of its Prineville, Oregon data center was 0.22 L/kWh, which Facebook considered a “great result.” We commend Facebook for releasing the WUE data and nudging others to follow suit. But, it is premature to pass judgment about what is a good, bad, or mediocre WUE. Facebook, itself, acknowledged this – recognizing the importance of benchmarking this metric against other companies and over time. The company will start disclosing its Prineville WUE data on a monthly basis, and in 2013 it will produce WUE data for a second data center in Prineville and one in Forest City, NC. We hope this will become a slippery slope toward the best practice of comprehensive water reporting and management, and that Facebook as well as other companies such as Google and Microsoft go beyond just showcasing best-practice sites to provide full context for their water usage.
Admittedly, water is more complex than other environmental issues. Unlike greenhouse gas emissions, which affect our global climate equally no matter where on Earth they take place, water’s geographical use matters a great deal. A company’s water footprint can mean different things based on the regional context in which it’s set. As a case in point, through our collaboration with AT&T we’ve learned that in water-stressed areas such as the South and Southwest, water consumed for commercial building cooling alone accounts for a hefty 10 percent of total regional water demand.
To get their hands around water impact, companies should embrace comprehensive water reporting. This starts with mapping out their water footprint to identify areas of opportunity. For example, AT&T’s water mapping revealed that 125 AT&T facilities account for approximately half of the business’ total water consumption. We believe water efficiency efforts should begin there, and indeed they are. As mentioned in this recent blog about our collaboration with AT&T, we are in the midst of piloting practices to reduce water use in building cooling. Our focus isn’t on a specific type of buildings; we’re looking to develop tools and insights that can generate water efficiency at a variety of facility types across diverse industries. We are exploring three approaches for this reduction:
1) Optimizing free air cooling;
2) Minimizing the amount of water blown down from a cooling tower while maintaining equipment integrity; and
3) Tapping into non-traditional technologies that further minimize water blow down.
We will release our findings in early 2013.
In the meantime, check out the following water disclosure and measurement tools that can help get your business up to speed on sustainable water management, easing pressure on the environment and saving you money:
• CDP’s water survey
• CERES’s Aqua Gauge
• WRI’s Aqueduct
• GreenGrid’s WUE and WUEsource
• World Business Council for Sustainable Development’s Global Water Tool
• Alliance for Water Stewardship’s upcoming water stewardship standard
Namrita Kapur is Director of Strategy for EDF Business, Environmental Defense Fund’s work that focuses on driving positive environmental change through corporate value chains. Namrita leads EDF's collaboration with AT&T, focused on reducing water use in commercial buildings; and directly manages our efforts to improve the efficiency of freight in companies.