Most often, utilities justify fixed-network advanced metering infrastructure (AMI) as a way to more efficiently acquire the data necessary for accurate billing. Fixed-network AMI systems that automatically collect data 24 hours a day, seven days a week, eliminate estimated readings and the need to physically drive by homes or send people to read meters.
Yet, while improved billing alone may provide the basic justification for fixed-network AMI, once a fixed-network AMI system is in place, utilities find that the AMI data collected can be used for much more than billing. What?s more, the network infrastructure of an AMI system supports additional devices that provide even more insight into the water system.
Water utilities can use AMI data to manage operations or to communicate with customers more effectively, encouraging resource conservation, improving customer service or reducing non-revenue water loss. How AMI data is used is totally dependent on the goals of the utility.
For instance, utilities in drought areas can both communicate how much and when each customer is using water, as well as what they are spending. The utility can use alarms generated by the analysis of water consumption to alert customers when the system detects constant use or use that does not conform to the usual. For utilities that want to recommend specific methods of conservation, such as doing laundry in the evenings when water demand is lowest, AMI data analysis can generate alarms that will trigger a message when the customer?s use is at its lowest. Finally, when a water ban is in place, all customers above the target use threshold can be alerted. The utility can also be notified should a visit to the customer premise be required to enforce the high water use ban.
Where non-revenue water management is the focus, utilities can apply AMI data to calculate true water loss. By comparing total consumption data measured at the meter to how much water is being pumped into a distribution system by the master meter, it is possible to establish a high confidence estimate of water lost to leakage. Once the utility understands how much water is potentially lost in the distribution system, it can initiate additional analysis to establish if those leaks are the result of inaccurate metering, unauthorized consumption or distribution leaks.
Once a pressure district is identified for non-revenue water reduction, utilities can use AMI data to determine whether meters need to be replaced. Water meters that have been in service a long period of time tend to under-report water use. By analyzing the performance of a meter over time using data collected by the AMI system, the utility may see a pattern that indicates the meter is slowing down. In addition, sometimes meters stop working altogether. Here, the AMI system will proactively alert the utility that the meter is reporting zero use. Without AMI, it takes utilities a long time to spot these non-working meters. Once the true level of water loss is established through data analysis, the utility can use leak detection tools such as Aclara?s STAR ZoneScan system to identify where the leaks are and evaluate their severity as input to field maintenance planning.
Presenting Data to Consumers
Presenting information about usage to customers is one way to easily and proactively inform consumers on how and when they are using water and what they need to do to conserve. Web-based portals developed specifically for water utilities can help both consumers make decisions based on AMI data. Currently, portals for consumers allow them to track consumption of water as well as understand their consumption in terms of real costs. Most portals allow the customer to compare use over time and to drill down to analyze total usage at the month, day or even hour. Knowing when use is at its highest enables the consumer to potentially shift discretionary water use (lawn care, filling the pool or laundry) to times when their personal usage is at its lowest.
Consumers can use portals to access near-real-time data from their smart water meters in an easy-to-use, web-based interface. For example, Aclara?s Consumer Engagement for Water portal presents simple charts and graphs that are easily understood by most users. These charts are provided in a turnkey solution, which reduces the complexity of integration into the utility?s web portal. Furthermore, Aclara bundles an authentication service with its water-use presentment to protect the privacy of each customers? usage data.
The charts provided by Aclara offer a complete view of daily, weekly or monthly usage, allowing consumers to see exactly how much water they are using, and when. If consumers see continuous usage, for example, they will know that their meters are running constantly ? a sure indication of a costly, on-premise leak.? Without access to AMI data, consumers often do not spot these leaks until they get a large bill.
Portals also correlate additional data with AMI data to enhance the customer?s understanding of consumption patterns and costs.? Aclara?s portal can overlay weather conditions such as average temperature on consumption charts, and provide consumers with insight into the impact of warm weather on water use. The total cost, calculated using the actual utility rates, can also be displayed through the portal so that the user can see how much they are spending on a monthly, daily and hourly basis.
For a few consumers prepared to vigilantly monitor daily consumption, it?s possible to manually identify continuous usage or unusual spikes, which are strong indicators of on-premise leaks. For those utilities and their consumers who prefer to be alerted when unusual patterns of behavior are detected, Aclara?s AMI alarms service will send the customer a notice via email or SMS when unusual consumption is detected.
Extended Infrastructure
Fixed-network AMI systems also offer a backbone infrastructure for other solutions that provide insight into the water system. Any device that can communicate over the fixed network can be used to collect information about the health of the water distribution network.
Today, solutions that operate on AMI infrastructure are being developed to do tasks such as pressure monitoring and leak detection. In fact, underground leaks are a major cause of unaccounted-for water that amounts to 20 percent or more of the water lost in the distribution system.
Aclara?s STAR ZoneScan leak detection system, for example, helps identify underground leaks before they break through the surface. Developed in conjunction with Swiss firm Gutermann International, the solution deploys on the fixed-network advanced metering infrastructure. It combines Gutermann acoustic loggers with specially designed Aclara meter transmitters.
The system places acoustic loggers on valves at regular intervals, usually around 500 ft, throughout the water pipeline network. The units function basically as microphones, picking up the sounds of water as it passes through pipes. This acoustic data is collected by the Aclara transmitters and sent back to the utility via the AMI network. Once the data from the loggers is at the utility, a cross-correlation is performed on it to identify within a few feet the location of possible leaks.
The District of Columbia Water & Sewer Authority (DC Water), which serves the 600,000 residents and 16.6 million annual visitors to the nation?s capital, recently conducted a successful pilot of ZoneScan that was designed to help it effectively find leaks in its aging infrastructure. More than 300 of DC Water?s 1,300 miles of water mains are more than 100 years old. The pilot program was able to find a leak that was subsequently repaired.
Although acoustic logging systems can be deployed without a fixed network, using fixed-network leak detection avoids the time and expense of manual or drive-by data collection. In non-automatic systems, loggers must be read at times when traffic is light because ambient noise can affect readings. This means that crews must be sent out in the middle of the night to collect readings, which can be expensive and inconvenient.
Acoustic leak detection can add value to fixed-network AMI. In the future, utilities may have the ability to add other field devices that do not require constant monitoring ? such as pressure sensors ? to their AMI networks.
When looking at creative ways to use collected AMI data as well as the fixed-network infrastructure on which AMI systems operate, utilities position themselves to maximize their investments in AMI. While additional uses such as leak detection and consumer engagement often are not part of the original justification for implementing an AMI system, they should be considered when evaluating the long-term benefits of fixed-network systems vs. other methods for collecting metering information.
Subodh Nayar is director of Water Software Product Management for Aclara Technologies LLC.
Todd Stocker is director of Gas and Water AMI Product Management for Aclara Technologies LLC.
