Drought-stricken city leverages advanced metering infrastructure to conserve water
Redwood City, a rapidly growing community in northern California, was feeling the effects of a three-year drought that stressed the volume of water the city buys annually from the San Francisco Public Utilities Commission (PUC) for its 83,000 water customers. Redwood City historically had used more water annually than the PUC was obligated to sell to it, and officials knew that unless they took proactive measures, heavy rationing and penalties for overuse were the next steps. Officials made initial attempts at water budgeting by focusing on monthly usage and rate reports, but these measures prompted customer complaints because results were released after water already was used.
Redwood City officials knew that a viable water conservation program required access to real-time meter readings that would give customers a reliable method of viewing their usage on demand, thereby encouraging customers to make proactive changes in consumption. Officials also knew that educating and supporting customers required a free flow of information between the utility and the customer, and that required an upgrade of information collection, meters and software.
Justin Ezell, water superintendent for Redwood City, said planners out together a programion that would accomplish their goals, dubbing it the Budget-Based Rates Program. Designed for irrigation customers, the program designates a specific amount of water each customer should use per month. Customers who stay in line with estimates pay the lowest of three rate tiers. Those who consume more than the budgeted amount pay higher rates based on the amount of overuse.
Because the program was designed to offer changing budget usage depending on the weather, it called for a water meter data collection system that could provide near-real-time and technologically advanced solutions—something with more flexibility than the current monthly read technology offered.
Redwood City turned to Sensus to learn about advanced metering infrastructure (AMI) and how the FlexNet two-way communications network could enable increased efficiency, reliable delivery of information, flexibility and customer service.
The fixed-base system, based on open standards, delivers hourly readings via a private licensed radio frequency available only to Sensus customers. Data is fed from the meter to strategically placed collectors, which transmit information via the Internet to Redwood City water division computers. The information is transformed into reports that detail usage, time of use and leak detection via diagnostics. Because most existing Redwood City meters were Sensus manufactured, upgrading to the AMI network was a simple, affordable transition.
FlexNet operates from collectors known as tower gateway basestations (TGBs). The 25 sq miles of mixed rural hills and urban flatlands that comprise Redwood City needed just two TGBs to collect the data from the 24,000 meters. The dedicated licensed radio frequency transmits at 2 watts of power to allow reliable service with minimal infrastructure, which eases the cost and environmental impact of the system.
By remotely reading meters from an office location, city staff can spend time quickly addressing leaks, educating customers about the program and supporting other customer service or system maintenance projects.
Putting a real-time, reliable data communication system in place allowed city management to move its progressive conservation plan forward. It was able to build the necessary Web applications, establish a level of trust with customers based on accurate reads and support strategic thinking because of the volume of newly accessible information.
"The AMI technology we now have in place is cutting edge, and we like to think of ourselves as a cutting-edge organization," Ezell said. "We now can empower our customers to conserve precious water resources while helping them reduce the cost of water."
With an information delivery system in place, the city used an in-house team to create a Web-based tool to calculate irrigation customers' water budget based on weather patterns and how much water a customer's landscape needs on any given day. The budgeting process also factors in the size of the family and property, existence of a swimming pool and landscape designs.
"Because irrigation schedules change daily, the system is a way to hold landscapers accountable. If it's raining, no one should be irrigating their lawn," Ezell said. "We still get questions, but now we can look on a screen and show them how to help themselves to this information and find the answers they need on their own."
Based on a customer's suggestion, an automatic e-mail module also is in use to alert customers of potential overuse or continuous leaks.
"We are saving millions of gallons in otherwise lost water just by identifying and correcting these leaks immediately," Ezell said.
Because FlexNet operates from a powerful, tower-based system, utilities are able to expand their service area footprint with ease. Plans are underway to extend the program to residential customers in hopes of even greater savings in the future, Ezell said, with plans for a five-year overall total coverage area deployment.
Redwood City achieved success in drastically reducing water usage after the first year of its pilot program. The conservation program saved more than 80 million gal of water (about 15%) in 2009 irrigation use compared to 2008. Some irrigation customers reduced their budgets and bills by $75,000. The program earned a 2009 Silicon Valley Water Conservation Innovation Award.
Redwood City customers now have access to daily water consumption records, including a chart of monthly, weekly, daily or hourly water use. With 24-hour access to their water accounts, customers can make adjustments prior to the end of the month so that they stay within their budgets and retain the lowest tier of rates.
"We benefit by the water savings, and our customers benefit by the monetary savings," Ezell said. "We are truly building a great community together."