Water-energy nexus and new initiative to drive water and energy savings
March 16, 2022
As part of Fix a Leak Week, today's MI Environment story by EGLE's Jake Wilkinson is from the recently-released State of the Great Lakes report.
Water and energy are inextricably linked in the drinking water and wastewater systems of a community. Broadly speaking, wastewater plants and drinking water systems can account for up to one-third of a municipality's total energy bill. Drinking water systems use energy to extract water at its source, transmit it to treatment facilities, treat it to satisfy safe drinking water standards and pump it through the distribution system to end users. Wastewater utilities use energy to pump, treat and discharge treated wastewater.
Many service lines in drinking water systems leak and often go undiscovered for long periods of time because they are upstream of the customer meter. These leaks are also a loss in potential revenue to drinking water utilities because the utility does not earn revenue from leaks that are upstream from the meter.
The American Water Works Association states that the average reported service line leak is 6.9 gallons per minute at 70 pounds of pressure per square inch (psi). Although their leakage rates are low, the annual volume of hidden leakage losses usually far exceeds the water lost in catastrophic, visible main break events. Average overall water loss in drinking water systems has also been estimated at 16%, with up to 75% of that being recoverable. Based on the inventory of service lines in Michigan, which includes the rated useful lives of those service lines and leakage rates, it is estimated that service line leaks result in over 21.5 billion gallons of water wasted per year statewide. Research has also found that municipal drinking water systems have a combined use of over 52 million kilowatt-hours (kWh) of electricity per year - enough to power almost 5,000 homes for an entire year.
EGLE's Energy Services is focusing on a series of projects to address this water-energy nexus in drinking water and wastewater systems, building upon previous successful programs. The Water-Energy Nexus project led by the Michigan Municipal Association for Utility Issues (MAUI) was created to quantify the energy used to treat and pump drinking water to end users in the drinking water distribution system. The purpose of the Water-Energy Nexus project is to assess how much energy is wasted in the distribution of water that leaks from water service lines in Michigan and to determine how much energy could be saved if service line leaks were reduced. The project focuses on leaks in service lines, which run from the water main to the end user. Another project underway by EGLE is the Water Leak Pilot Program, which was designed to repair water leaks in the communities of Highland Park and Benton Harbor. Targeting 100 homes in each community, the program is focused on reducing a home's water use through the repair of leaking pipes and replacement of old, inefficient fixtures. Initial data has shown in Highland Park that half of homes with completed repairs have reduced residents' water consumption by 50% or more. Water reductions in the homes will save not only water but also energy. Hot water loss reduction will reduce the homeowner's energy costs, and cold-water loss reductions will save energy for the municipal system in line with the findings of the Water-Energy Nexus project. Project work is still ongoing but has been well-received by the communities and lessons learned can be expanded to other communities across the state.
EGLE sponsored Fix a Leak Week in March 2021 to address plumbing and water system leaks in residential homes. This event focused on:
- Sharing educational materials about the importance of repairing water leaks.
- Developing a directory of water conservation and plumbing repair resources available to Michigan residents.
- Engaging with partners to develop policy and funding recommendations to support water leak repair efforts in disadvantaged communities.
EGLE has also signed onto the U.S. Department of Energy's Sustainable Wastewater Infrastructure of the Future (SWIFt) 2.0 accelerator program, which will result in using less energy to process water - reducing both the cost to process water and its carbon footprint. SWIFt Phase 2 (SWIFt 2.0) will continue the momentum of the Phase 1 pilot program by leveraging the tools, resources and lessons to benefit the broader wastewater sector. EGLE will assist in facility engagement and peer exchange forums, as well as assisting participating facilities in the development of an infrastructure improvement plan. These efforts will help wastewater facilities by connecting them to energy management best practices. In addition, wastewater utilities will receive technical assistance to support planning for strategic infrastructure upgrades that incorporate energy efficiency measures and contribute toward reducing the amount of energy needed to process the wastewater.
These programs all address the significant energy consumption embodied in the treatment of and distribution of water for customer use as well as treatment of water collected by sewer systems in Michigan. These programs can help reduce the substantial costs associated with water systems in a community and help communities on their path to carbon neutrality and water stewardship.
Caption: Broken leaking blue water service line. Photo courtesy of Ottawa County Road Commission.