Save Water—Save Energy, or, Save Energy—Save Water
The water/energy nexus is a growing area of opportunity for energy efficiency companies. In 2010, Johnson Controls published â€œSavings Multiplied: Conserving Water and Energy to Maximize Efficiency and Reduce Emissionsâ€ a white paper that addresses water and energy savings technologies and practices, along with various case studies. One of the studies presents Johnsonâ€™s efforts at its Glendale, WI, headquarters, where water efficiency methods on the five building campus include a 30,000-gallon cistern to capture rainwater from all new roof surfaces; a graywater system to flush toilets, reducing potable water for bathroom fixtures by 77%; high-efficiency plumbing fixtures; permeable pavers that allow rain and snowmelt to filter through parking lots and move via groundwater to a retention pond; and green roofs to reduce runoff.
Water and energy are hot topics for the American Council for an Energy Efficient Economy (ACEEE), according Eric Mackres, the Councilâ€™s senior analyst and local policy lead.
â€œThe water efficiency and energy efficiency communities are aware of each other but havenâ€™t worked directly together to try to solve problems, and thereâ€™s a lot of opportunity,â€ says Mackres. Much of that opportunity is presented in a publication coauthored by Mackres, Addressing the Energy-Water Nexus: A Blueprint for Action and Policy Agenda. Mackres notes that the ACEEEâ€™s efforts included participants working in professional capacities and nonprofits, government agencies and other research labs and organizations, and firms and manufacturers.
â€œGovernment buildings offer an opportunity, and thereâ€™s a lot of different ways of thinking about water usage and energy usage,â€ notes Mackres. â€œYou can effectively target water and energy consumption in buildings, and one of those examples would be government buildings and public buildings. If you can reduce demand for water, you donâ€™t have to worry about the treatment plant as much, because your need for new equipment and capacity decreases. In some cases up to 20% to 25% of a local governmentâ€™s energy costs can be just water treatment and distribution.â€