(UtiliPoint.com - Sept. 20, 2006)

www.utilipoint.com

September 20, 2006

By Patti Harper-Slaboszewicz Director, AMR and Demand Response

Interval consumption data, an emerging industry standard for electric utilities, is now being considered as a tool for conservation and customer service for water utilities as well. Even time-of-use rates for water are now envisioned, possibly including dynamic rates. Many water utilities have invested in mobile automated meter reading (AMR) to eliminate estimated bills and save on meter reading costs. The cities of Denver, Houston and Philadelphia are three recent examples of large rollouts of mobile AMR. While most water utility AMR deployments are still for mobile AMR, some utilities have begun installing fixed networks. Colorado Springs and Boston are two large water utilities that opted for fixed networks. UtiliPoint expects this trend to accelerate with new networks using more powerful endpoints yet still allowing utilities to plan on a 20 year battery life.

Rather than a transmission range of hundreds of feet, new endpoints now available from several vendors can regularly transmit for miles, up to five or six miles in some locations. The longer range of the endpoints means less investment in network infrastructure. This significantly reduces the difference in cost between deploying a mobile AMR network and a more advanced fixed network. Combine the power of new endpoints with the high cost of gasoline and a new appreciation for benefits beyond meter reading, and it's not hard to see the attraction of fixed networks for water utilities.

Helping Customers Find Leaks Before They Lead to Large Bills

And, just like the electric industry, water utilities are moving beyond just doing what they used to do more reliably and faster by looking at other benefits a fixed network might provide. For example, with interval meter readings on water, utilities can find customer leaks proactively. One utility, Cucamonga Valley Water District in Southern California, estimates that 10 percent of their water customers had detectable leaks and two percent of their customers had significant leaks. Darron Poulsen, Cucamonga's customer service officer for the district, said they have been knocking on people's doors telling them of major leaks, saving customers money before they receive their bill, rather than after. The emphasis is on improving customer relations rather than saving the utility money. It is much better, Poulsen explains, to help customers find leaks quickly than it is to argue about high bills after the fact.

Cucamonga finds the leaks by collecting interval consumption data, and using a special software program from Itron that looks for unusual patterns of usage that are suggestive of leaks. One clue to a leak is if water usage at a home or business never drops to zero for an extended period of time. Even with teenagers staying up late and dishwashers, sprinklers, and washing machines scheduled to run early in the morning, in most homes there is some period of time each day where water usage drops to zero. If not, there is likely leaky plumbing or a problem with the sprinkler system. Customers may not be aware of how much water is wasted from leaky plumbing, and often do not see any evidence of sprinkler problems.

Water Pumping Similar To Electric Generation

Interval data provided to customers can also educate them on how water is used. Cucamonga, like many other water utilities, faces higher costs to provide water. In the last 40 years, Cucamonga grew from a community of 10,000 people to over 200,000. Aquifers are not being replenished, importing water is more costly, energy costs to pump water are increasing, water treatment costs are increasing, and labor costs continue to rise. Conservation is a key goal of Cucamonga because there are no prospects of less expensive water in the future.

Water utilities, under pressure to provide sufficient water at reasonable costs, are beginning to consider time-of-use rates more commonly associated with electric energy rates. The usual explanation for time-of-use rates for energy is that electricity can't be stored—it must be generated at the time the energy is used. But, water can be stored, so why would water utilities need time-of-use rates? The reason is tied to pumping: water has to be pumped everyday to fill local reservoirs. Figure 1 shows the energy use profile for a large water utility. Note the degree to which pumping needs drive energy use.

Figure 1 Energy Use Profile of a Large Water Utility

Source: Derceto, Ltd.

Water utilities typically face time-of-use rates for energy to drive those pumps, and pumping constitutes over 90 percent of a typical water utility's energy bill. The driver for time-of-use rates for the water utility's customers is to reduce customer usage when the utility is pumping. If too much usage occurs when the water utility is filling the reservoirs for daily water use, instead of using gravity to deliver water to customers, the utility essentially ends up pumping water to customers, increasing their energy usage and costs.

For utilities in regions where water conservation is needed, time-of-use rates can also encourage conservation by setting up rates that encourage customers to water their landscaping every other day, rather than daily. Interval data allows customers to monitor their own water usage rather than assigning water utilities employees to drive around looking for customers watering on the wrong day. Utilities could design rates where customers are charged a higher price for daily water use over a certain threshold on odd or even days, or on certain days of the week. The threshold might be based on individual account history, or on an average volume for the service territory.

Reducing Line Losses

Customers are not alone in having to contend with leaky pipes. Water utilities with older distribution systems are also prone to leaks. While the water utility may be aware of leaks, it is difficult to locate leaks in underground pipes. One method of finding water distribution leaks is provided by a small company, Flow Metrix, which detects leaks using acoustic sensors (usually one sensor per ten water meters). (Flow Metrix has recently been purchased by Itron.) The sensors are permanently installed on water service pipes near a water meter. Like water meter modules, the sensors operate on a battery, and transmit data using radio frequency (RF) signals. For a utility with a fixed network and concerns about leakage in the distribution system, the fixed network could support both meter reading and daily collection of data from the acoustic sensors.

The acoustic sensor system, called MLOG, records sounds inside the water distribution pipes for four hours during each 24 hour period. The data can then be uploaded through a network (such as a fixed AMR network), which is then analyzed by an application provided by Flow Metrix. The software analyzes the sound data recorded and computes a Leak Index for each MLOG Logger and assigns a leak status as shown below in Figure 2. In the map of the distribution system shown in Figure 2, the small red dot shows a probable leak. The color inset on the left side of Figure 2 shows an expanded view of the area of the distribution system suspected of having a leak.

Figure 2 Flow Metrix Color Coded Overlay Showing Probable Leaks in Water Distribution System

This is another example of how water utilities are expanding the utility of a fixed network AMR system to achieve additional operational benefits. If a utility works to tighten up its distribution network, it should be easier to convince customers that their conservation efforts are worthwhile.

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