Migrating to AMI

Recent advancements in metrology are delivering water utilities unprecedented intelligence to help them increase revenue, support conservation efforts and provide better customer service. While electric utilities leverage new technologies including advanced metering infrastructure (AMI) systems to create a smarter, more effective power grid, water utilities are also leveraging these technologies for improved measuring of water supply and monitoring of distribution systems to support proactive leak detection, reduce the risk of supply interruptions and deliver improved customer service.

In an environment where nearly two-thirds of states expect to experience water shortages before 2013, the impetus to update an aging infrastructure and better manage water resources has never been greater.Historically, automated meter reading (AMR) systems that sent billing information to the utility were deployed as an initial step toward driving greater efficiency. However, the AMR systems, with one-way communication, fell short of the two-way communication features inherent in an AMI fixed-base system.

For this reason, many utilities are now making the investment in AMI fixed-base systems that enable two-way communications between the utility and the meter to proactively identify and solve problems such as leaks and connectivity issues. This helps water utilities preserve revenue and provide greater customer service, all while further increasing operational efficiency. ?

The Utilities Department of the City of Santa Maria, Calif., experienced the benefits of deploying a fixed-base AMI system. The results were clear after a 45-day pilot project which identified leaks in 3 percent of homes in the test area, but nearly a year later officials conservatively estimate that more than 2 million gallons of water have been saved.

Making the Switch to AMI

In 2007, the Santa Maria water utility was 25 percent of the way through installing an AMR system when an extensive lifecycle cost analysis showed that upgrading to a fixed-based AMI system would ultimately provide greater benefits.

The utility estimated achieving a full return on investment in an AMI system in a matter of a few years, even after factoring in the cost of replacing the initial installations of the AMR system. This return would be derived based on savings from reduction in staff time and vehicle costs spent on drive-by readings. Additional revenue would also be captured by increasing the frequency of meter reads from monthly to hourly for earlier leak detection and improved accuracy in measuring and billing, both of which would also help the utility improve customer service.

Water utility officials developed a list of minimum required qualifications for an AMI system, including that the network operate on private, FCC-licensed spectrum. Licensed spectrum offers high power of transmission with low noise, dramatically increasing the range, throughput and performance of communications when compared with networks communicating via unlicensed spectrum.

Based on this and other criteria, including the cost of installation, towers and other system components, the utility ultimately chose to deploy the FlexNet AMI communications system from Sensus.

Pilot Program

To forecast the return on the required investment for deploying an AMI system, Santa Maria city officials requested that the water utility develop a pilot program to test the range, performance and results that the technology offers.

A pilot program ? designed in part to challenge the reach of the proposed AMI communications network ? successfully demonstrated savings of both water and money. To test the full extent of the system?s range, water utility officials used one tower to read three reading books, or groups of meters typically read on a drive-by route, that were geographically disparate. The AMI system proved successful in uploading information from the meters to the utility for analysis.

The technology identified leaks in nearly 3 percent of the homes in the test area, equivalent to 2.5 acre-feet worth of leaks. Santa Maria officials credit earlier leak detection with saving nearly a half million gallons of water ? and hundreds of dollars for customers ? in the first 45 days of the pilot. This pilot proved influential in confirming the true cost and water savings advantages of running the AMI system, justifying the costs of initial implementation.

Full Implementation

Based upon the pilot program?s results, city officials demonstrated that individual customers with water leaks were able to save hundreds of dollars on their water bill from leak identification alone. The FlexNet system would enable greater conservation of water and reduce the amount of water the city must purchase from the state.

AMI installation began in November 2009 and by early December the first leak had been identified through the system. Data gathered in October 2010 showed that in less than a year, the AMI system has helped save a conservative estimate of 8 acre-feet of water, or more than 2.6 million gallons.

The AMI system has enabled improved quality of customer service as representatives are able to access accounts, locate leaks and in many cases identify the source of a leak instantly, from their desk, where they once had to schedule and conduct on-site analyses. Leak detection time has been cut drastically from one month to a matter of days as new registers read every one cubic feet of water vs. 100, providing information on an hourly basis. Customers have responded quickly to fix leaks identified on their property, saving money on their water utility bills.

In one case, a customer without a fixed base meter installed at his property believed his water bill was too high. The city promptly installed a fixed-base meter on the property and was able to identify that the sprinkler system was running twice during the night. The customer had been unaware that this was occurring and was able to reduce the bill simply by adjusting the irrigation system schedule.

Santa Maria had implemented tiered water pricing rates based on usage prior to installing the AMI system, and by providing customers more detailed usage information customers are able to make behavior changes that keep their water usage within the lower pricing tiers.

Santa Maria will complete the current deployment of this system in February 2011, installing approximately 7,200 meters. Santa Maria utility staff have managed the installation process and other necessary alterations to the utility?s daily management have been implemented smoothly, such as changes to billing procedures. Utility officials are considering expanding the AMI project to encompass all 21,000 meters in the Santa Maria system.

Careful planning and analysis enabled Santa Maria to successfully transition to a fixed-base AMI system that will allow it to reap rewards for many ensuing years as the city preserves previously lost revenue, supports conservation efforts and improves customer service. The lessons learned will provide valuable insight and experience as water utilities across the country continue to adopt new technologies that will transform the nation?s aging infrastructure and set new standards in customer service.

Shannon Sweeney is water resources manager for the City of Santa Maria, Calif.

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