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What’s a Smart Meter?
This photo is a Smart Meter that will be installed on homes in Naperville.  The manufacturer is Elster, model “Rex2.”
Residential Smart MeterAs defined by Citizen’s Utility Board, “a “Smart grid” is an umbrella term for Internet-based upgrades to our “power grid” — the lines, wires, and power stations that deliver electricity to our doorstep. Our current system consists of one-way communication, with electricity that was literally generated a second ago simply being thrown onto the grid for our consumption. A smart grid, however, would be based on two-way communication, potentially allowing homes to automatically alert the utility of costly problems and consumers to adjust their power usage at key times to cut their costs. If done correctly, a smarter grid could save Illinois consumers billions of dollars by reducing power outages and cutting energy waste. But the jury’s still out on whether the benefits of a smart grid would outweigh the costs. The state and consumer advocates want to answer that question with a ComEd pilot project.”

What exactly is a smart meter?        A typical, analog electric meter has tiny mechanical dials that someone—you or a utility worker—has to read each month (or bi-monthly) in order to report the home’s measured power usage.  There are no dials on a Smart Meter. It has a digital face, and unlike analog meters, it can send—automatically and almost instantly—your power usage to the utility.  Some digital meters are not “smart.”  If its wireless, it will say “FCC ID” on the face of the meter.

The digital Smart Meter records electric usage data as often as every minute or as infrequently as every hour around the clock.  Naperville, in its search for a Smart Meter vendor, requested that some residential Smart Meters be able to read at 5 minute intervals and other residential meters read every 15 minutes.  The Smart Meter transmits the data collected via a wireless radio frequency (RF) network back to the utility.  According to documentation from a California utility (PG&E), a typical meter uses its wireless communications (for any one of multiple functions, including time synchronization, pings/wellness checks, and network “chatter”) every 6-8 seconds.  Meters closer to a Gatekeeper can be communicating even more frequently.   Non-residential buildings, such as businesses, churches, and SCHOOLS, will communicate at least as often.

Tropos and Collector Gatekeeper

Photo by Jennifer Stahl, Naperville Smart Meter Awareness

Naperville Mesh Network components: 
The electric network access point [Collector meter/Gatekeeper] collects meter data from nearby [residential or commercial] electric meters and periodically transfers this data to the utility via a cellular network.  Each wireless device (Smart Meter) communicates to several other smart meters nearby, which function as signal repeaters, relaying the data to Gatekeeper.  The Gatekeeper aggregates, encrypts, and sends the data to substations, firehouses and police stations over a wireless network, which are the Tropos [a box with 4 white tubes sticking out the top, located atop light poles, as seen in the photo above].  Once the data reaches a substation or firehouse, it travels via the fiber optic system back to the utility. The mesh continually optimizes routing to ensure information is passed from its source to its destination as quickly and efficiently as possible.
The system supports two-way communication between the meter and the utility.  Smart Meters can be upgraded remotely, providing the ability to implement future innovations easily and without notice to the customer.
The Smart Meters that Naperville purchased also have remote disconnect switch, a piece of internal hardware.  This allows the utility to remotely turn off power upon request (e.g. when selling the home and leaving it unoccupied or for non-payment of bills).  This disconnect switch can also be activated remotely via the Utilty’s load control management software system.  The system can be set to identify a maximum load and should a meter reach that maximum, the system would automatically shut off power to the home for a default period of 15 minutes.   An example of this would be a hot summer day when you’re having a party and using a lot of power to run your appliances, lights and air conditioning.


WHY is Naperville doing this?

The following 2 documents describe Naperville’s plans.  Much more information is on the city’s website at Naperville.il.us/smartgrid.aspx


Other photos of Naperville Mesh Network components are below.  The device with four white tubes at the top of the pole is called a Tropos.  This wireless device is wired to a Collector Meter, a.k.a. “Gatekeeper,” a gray box on the curve of the light pole.  The Gatekeeper collects usage data from approximately 400 homes in the vicinity.

Chicago at Ellsworth

Photo by Jennifer Stahl, Naperville Smart Meter Awareness

Chicago at Ellsworth (North Central College in front of Wentz Hall)


Aurora Rd. west of River Rd.

Photo by Jennifer Stahl, Naperville Smart Meter Awareness

Aurora Rd. west of River Rd.


Collector Meters on Naperville Telephone Poles

Photo by Jennifer Stahl, Naperville Smart Meter Awareness

Gartner Rd. near Charles St.


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