Four Cornerstones for Integrating Water and Energy Systems
Water is life
It is the only utility service that customers ingest. Yet it is often the invisible utility, undervalued and underfunded. Recent wake-up calls have instigated city responses:
- The Flint, MI lead crisis is an ongoing saga of contamination impacts. Cities like San Francisco, CA and Washington, D.C. are utilizing the green bond market to upgrade stormwater and wastewater management and infrastructure.
- Legionella outbreaks from building water features and cooling towers are becoming more frequent. Cities like Vancouver, B.C. are partnering with entities like the National Science Foundation to create a methodology for cooling tower inventory and code adjustments.
Energy is income
In the digital age, no power means the inability to work.
- As witnessed with the recent fires and power outages in California, dry conditions combined with a lack of proactive maintenance claims lives and costs billions.
- Cities like Boulder, CO and San Francisco, CA are trying to create their own energy utilities so they can control energy portfolios and maintain local grid systems.
Constraints are shared
Equitable and continuous access to water and energy is increasingly an indicator of community resilience. They must support, not compete with, each other, because:
- Increasing air and water temperatures means increasing water treatment to maintain public health standards, as well as reducing power plant generation to maintain discharge standards.
- Decreasing water availability due to less precipitation and snowpack means increasing difficulty in pressurizing water systems and meeting demand, as well as reducing available energy generation from fuel supplies requiring water for extraction and processing.
- Increasing intensity of storm events, storm surge, and flooding means increasing risk of water contamination, and increasing risk to the electrical grid, water treatment plants, and power plants.
Leading with partnership
Because water is required for energy creation, and energy is required to operate our water systems, some cities are turning the relationship into an iterative cycle of planning and implementation. They are seeing the interconnection as critical to their climate resiliency goals and dedicating resources to this process. For instance, the City of West Palm Beach, FL recently advertised for a Sustainability, Water, and Energy Project Coordinator to help them meet their greenhouse gas reduction targets by working across systems. When the many examples of cross-sector collaborations at the intersection of water and energy are examined together, four cornerstone approaches emerge:
|Building Trust||Involving each other in organizational planning processes||The City of Las Cruces, NM’s Sustainability Office and Utility will host a leadership workshop in 2020 to develop a shared community approach to water and energy conservation|
|Training staff across water and energy systems||The City of Orlando, FL’s Utilities Commission train staff on water and energy system processes, building skills and empathy across departments|
|Providing affordable, equitable, and transparent service to shared customers||The City of Dubuque, IA’s Interstate Power and Light and the Dubuque Water Utility Dept. use a dashboard to connect customers to their water and energy use data in real time, allowing rapid response to water leaks and power outages|
|Leveraging Joint Customers||Offering joint rebate, and/or incentive programs||The City of San Antonio’s Water System and electric utility ran a high-efficiency washing machine rebate program, allowing the customer to get a rebate from both utilities with just one application; a case study on how they work together is here|
|Developing joint customer-facing pilot projects||The City of Austin, TX partners with their water and energy utilities to provide weatherization assistance to low- and moderate-income customers|
|Engaging in dual community outreach||The City of Medellín, Colombia specializes in water-energy conservation campaigns, doing demand-side management and leak detection for all customer types (residential, commercial, etc.)|
|Sharing and Optimizing Data||Collecting and sharing data across systems||The City of Burbank, CA’s Water and Power deployed 50,000 water and electric smart meters that communicate over the same network and share a data management system|
|Approaching data management, display, and assessment with the customer||The U.S. DOE’s Better Buildings Better Plants program asks for voluntarily water and energy data, while cities like New York, NY and provinces like Ontario, Canada have mandatory benchmarking reporting requirements on building water and energy consumption|
|Planning for a smart network approach together||The City of Palo Alto, CA’s Utilities envisioned a smart grid system within a comprehensive 5-10-year Utilities Technology Roadmap for water and wastewater, electric, fiber optics, and gas utilities|
|Investing in Connecting Infrastructure||Sharing metering infrastructure||Glendale Water and Power, a municipally owned utility in Los Angeles County, CA procured and deployed smart water and electric meters from a single vendor in its entire service territory|
|Connecting water system energy generation to electrical grids||The Borough of Caldwell, N.J partnered with the Public Service Electric and Gas Company to install a solar storage system with battery back-up at the wastewater treatment plant, to provide additional resiliency to both water and energy systems|
|Increasing resiliency with decentralized water and energy systems||The City of Stockholm’s Hammarby Sjöstad district recaptures energy when treating wastewater and uses it for district heating|
Consider water conservation as an energy savings measure
- Green Stormwater Infrastructure (GSI) and low-energy rainwater harvesting reduce the volume of potable water necessary to maintain urban canopy, and avoid the energy consumption that would have been required to move and treat excess stormwater.
- To help Milwaukee, WI adapt to climate change while creating a healthier and more resilient city, the city introduced a community-wide green infrastructure plan that calls for 36 million gallons of stormwater storage from GSI. This is the equivalent of adding 143 acres of community green space.
- Smart irrigation allows for local watering scheduling design that can meet specific landscape and community vegetation needs while also reducing the energy required to run irrigation systems and treat unused runoff.
- The Spanish Fork City, UT Water Conservation Program piloted a smart irrigation controller program, offering online signups, installation, and staggered watering times to avoid windy periods. The 2,000 pilot homes with smart controllers saved an average of 4,500 gallons per month, decreasing the average use of each customer by 17%.
- Non-potable water use can diversify supply and sometimes, combined with thermal energy recovery systems, generate electricity while reducing the pumping energy costs of centralized treatment facilities.
- The University of Texas at Austin captures condensation from air conditioners to feed cooling tower basins at their power plant, reusing water in their building energy systems.
Optimize systems to reduce waste
- Water and energy audits are the starting point to making utility operations more efficient. Saving measures identified through these system-wide audits can include: resolving low pressures in water lines that impede delivery to users; identifying pumps that are running unnecessarily; reducing the amount of water an energy plant consumes by adapting daily operations; and upgrading equipment, pipes, and wires to reduce water and energy losses during transmission.
- A smart meter study in Sacramento, CA monitored leaks and provided an online portal with leak detection notifications and alerts for customers. Leaks detected at locations where customers accessed the online portal were 34% shorter than average.
- Decentralized and distributed water and energy systems reduce resource losses by shortening the distance and costs of treatment and transmission. Consider non-wire and non-pipe alternatives that replace traditional infrastructure, allow for targeted responses to daily water and energy demands, and ease the load of centralized electric grids and water piping systems.
- The U.S. Army’s Fort Hunter Liggett combines solar photovoltaics and batteries to be able to withstand a 24-hour power outage. This microgrid reduced energy use by 30 percent between 2003 – 2015 and reduced potable water use by 57 percent between 2007 – 2015.
Generate energy in water and wastewater systems
- Large- and small-scale hydropower systems capture embedded energy in water to generate electricity. Either by releasing water from dams that have associated power plants, or by equipping gravity-fed water pipes with in-line turbines, energy can be generated in closed and open water systems alike.
- The City of Portland’s Water Bureau has been partnering since 2015 with a private company and an energy utility to install and operate generating turbines in water pipes. The energy is then purchased by Portland General Electric, putting an average of 1,100 megawatt hours per year on the city’s power grid – enough to power around 150 homes.
- Solar arrays and wind turbines at water utilities facilitate greater energy independence for local water and energy systems alike. The electric grid load required to operate the water plant is reduced, as is the water utilities’ monthly energy costs. Depending on the size and design of the renewable energy system, some water systems can operate during broader power outages.
- The Jersey-Atlantic wind farm is located at a wastewater treatment plant in Atlantic City, NJ. After 11 years in operation, the wind system saved the utility over $5.2 million dollars.
- Wastewater byproducts conversion is a way to capture energy from water waste. Using methods such as incineration, anaerobic digestion, or bioconversion, electricity can be generated and landfill waste, methane gas production, and hauling costs can be reduced.
- Washington, D.C.’s Water and Sewer Authority installed a thermal hydrolysis process system at its wastewater treatment plant. It generates energy from the steam and methane created when processing solids, and nets 10 megawatts of electricity.
Store energy in water and energy systems
- Pumped storage is when water is moved to a higher elevation during off-peak times of day and night, when electricity is cheaper. It is released through an energy generating turbine during peak-demand periods, when electricity is more expensive. This system allows utilities to handle extreme hot and cold periods when demand spikes by cost-effectively harvesting the energy embedded in the stored water as it is released.
- The Ludington Pumped Storage Plant provides services to over one million residential customers. Water is pumped from Lake Michigan to a 27-billion-gallon capacity upper reservoir for release on demand.
- Battery backup systems can help electrical grids deal with the generation intermittencies of renewable energy systems. Like pumped storage, they also supply energy captured during off-peak times for use during peak-demand times, allowing for energy cost savings.
- In 2016, the Irvine Ranch Water District announced a 7 MW, 34- MWh installation of Tesla lithium-ion batteries at 11 different sites across Orange County, to reduce grid reliance.
The Applied Water-Energy Nexus: A Framework for Local Water and Energy System Integration is a tool built to facilitate mutual consideration of local water and energy systems by local decision-makers. The framework is based on the following hypothesis, which is proven by example:
- If cities proactively partner across jurisdictions to tailor their own approaches to community water and energy system integration, then they can face the uncertainties of changing climates and populations with more reliable, affordable, and resilient water and energy supplies.
Integration is a culture to cultivate and it is happening at the local level. It begins with communities answering questions like these:
- Are local water and energy supplies and systems secure against climate and population changes?
- Are they being considered together?
- Do goals and actions align across city plans, water utility plans, and electric utility plans?
If not, can the city play the role of convener, and start the conversation?
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