"Smart" or Demand Metering
"Smart" or Demand Metering or Automated Meter Reading (AMR) has been around since computers came along. They have been used by the electric utilities to monitor large customer usage to identify their Peak Power Usage times and duration, Reactive Power content, and their Total Consumption for revenue purposes. These applications consisted of dial-up connections where a computer would dial through a voice-grade phone line that was connected to a meter with a modem, and once a connection was made, the various data points requested were downloaded to the big mothership. For those old enough to remember, Internet access used to be pretty much the same.
However, the desire by some for consumer information, and the consumer desire for lower utility rates, have cornered the utilities into identifying the means of satisfying both needs by reducing personnel (meter readers), and rolling out large-scale application of automated metering. While this automated metering can be applied to Water, Gas, Electric, and other services limited only by the imagination of the design engineer, the ones of most interest to the reader seem to be those applied to Electric Power Usage, which will be the focus here (although the concepts described apply equally to all utilities' AMR, except for metering on the powerline). Bear in mind, that unless you are fully disconnected from the infrastructure grid, you have a contract for services with several utilities. This contract may severely limit your desire of not having automated metering applied to your services. While their use poses valid privacy concerns, whereby your usage can be tracked to identify with excellent accuracy your daily activites, that is entirely another matter. Many permutations of AMR exist, in a non-exhaustive list as: 1) wired to the power system with direct modulation, 2) wired to the power system via Powerline Carrier (see the Broadband Over Powerline presentation also provided here), 3) wired via telephone line, 4) wireless activated by drive-by (Mobile AMR), 5) wireless by peer-to-peer (mesh) networking. Any of these can provide data collected daily, hourly, minute by minute, or every data collector's dream (not presently available, but on the drawing board) - real-time data.
One of the early consumer incarnation of Automated Meter Reading (AMR) was with the Turtle AMR, whereby a module on the meter would impress digital data right onto the power wiring. The primary frequency was in the order of five to 9.5 Hz (5 - 9.5) and was either coded as a Morse-type intermittent signal, or continuous and modulated with the desired data. Many users in a gepographical area meant that there were many frequencies within that range in existence at any one time. Graphically it would look like the sketch below. The author believes application of this form of AMR is waning, because data transport is slow.
Note that the graphical display on an oscilloscope would only consist of the blue
trace, whose Peak value reaches 170 Volts, on either side of Zero, depending on whether
that particular peak is positive or negative. The Turtle AMR signal consists of a
clipping of that peak below 170 volts, such that over time, the clipping or
non-clipping would equate to digital data at whatever the chosen frequency happens to
be. The clipping action is higlighted here by the author-inserted connections to
show the two frequency scheme, the 60 Hz power and the 6 Hz AMR.
There are some valid concerns here. Namely that the frequency used for data cartage is within the range of brain waves, and since it is directly impressed on the power wiring, its conveyance is not only toward the electrical substantion data collection point, but also toward the indoor living space. Considering that more that about 90% of Morth American homes use Romex wiring, a wire that allows the Voltage to produce Electric Fields indoors, leads one to immediately conclude that the AMR data frequencies are immediatelky available to the consumer as a whole-body exposure via Transformer Action, as highlighted below.
Note that in a typical home there are many wires scattered about, sometimes resembling
the bars of a birdcage, all energized and emitting Electric Fields 24/7. This sketch only
depicts one partial loop to demonstrate that encircling the body and causing Transformer
Action, whereby the exposed subjects experiences Internal Voltages and Currents that mimic
the original signal, is downright easy. Critics will immediately argue that there's not
enough signal to elicit biological response. However, the body can respond to the frequencies
as well as the intensity, so "windowing" effects can be identified, even at very low levels.
In all of this, bear in mind that the entire gist is to perform the same function in a less expensive way - we wanted it this way, and therefore the utilities are constrained into providing it this way. While this may be a good motive, the consequences may be undesirable, and once in motion, there may be no reverting back as utilities cannot (and will do their utmost to not) cater to each individual individually, as this would cause cost increases that would have to be passed on to the consumer. Oh, no! We did it to ourselves . . .
A no-impact AMR metering scheme would be the one long employed by the utility with large usage customers, with a voice-grade telephone line to each meter, but this goes against the grain of least-cost efforts.
BPL metering would employ the BPL carrier that is anywhere between about 50 KHz and 500 KHz. The digital data would be impressed upon this higher frequency carrier, and data cartage speed is fast compared to data directly modulated onto wiring as in the Turtle described above. Considering the previous elaboration of Electric Field presence indoors, we now possibly have this higher frequency present indoors. The body is mostly transparent to frequencies in this range, and the modulation scheme may be complex enough that the body's response, if there is one, may be hard to predict or categorize.
We now come to Wireless AMR, whose data cartage speeds are much, much faster.
Mobile AMR involves a Radio Frequency (RF) receiver within the meter that is always listening. When an operator comes driving by, the operator's equipment will be broadcasting a series of keying codes specific to the route traveled, and in sufficiently close proximity the meter's receiver keys the transmitter and send the data to the mobile operator's electronics. The frequency will vary by vintage of the AMR component's manufacture, but most likely is faster than 100 MHz. The data is infrequently keyed, is of low intensity, and while more economical than walk-by operators, is not as economical as operator-less metering.
Fixed AMR or wireless and operator-less metering is the least expensive, after the cost of the inital roll out. This type uses frequencies typically in the upper hundred MHz, perhaps close to, or even identical to, cellular frequencies. Some use 2.4 GHZ, which is non-licensed, as it was initially intended for Industrial Scientific and Medical (ISM) usage. The next time you get a chance to look at a microwave oven up close, look at its back, and you'll see a label identifying its operating frequency as 2.4 GHz. Surprised?
Fixed AMR is / was designed to be available to send data 24/7 to a central collecting point on a polled basis, similar to a cellular tower polling a couple of hundred cell phones in a recurring sequence. The data polling must of necessity be infrequent due to the limited storage of any data collection device to collect data on a predetermined basis, lest the recording device become overloaded and stop recording. Data storage increases the cost of the data collection metering, and there is no continuous monitoring of data because it is a technical impossibility in a digital world. The best one can achieve is data collected every 5 seconds perhaps, and even that loads up data storage quickly. A simple solution to download such data and restart the data collection cycle is to poll the metering on a more frequent basis. So if you were told that the data is polled once a month or once a week, you may wish to consider that it is being polled every couple of hours or faster.
Mesh AMR is the type where AMR units talk to each other locally, perhaps to limit the transmit power requirement and extend battery life, or perhaps to reduce the number of wireless antenna installations (also reducing the number of residential objections to such contruction).
The faster data is collected and passed on, the more data can be collect and processed. The data collected can quickly identify living habits of the user, and open them up for pointed marketing from the utility or those for whom the data ends up being the final destination. The data can be sold to whatever market is available. Can you picture your every action being processed, by an unseeing unfeeling machine, that can determine based on even just the amount of power used, and the time of its occurrence, and the usage of water, and its occurrence, what you are doing in your private residence minute by minute? Is that invasion of privacy?
By necessity. this document can only present the highlights of AMR. The latest objections being the presence of RF with the AMR. The power levels are obviously below the thermal threshold, so the FCC is out of the loop. If there is genuine biological response, then it most likely is associated with the type of modulation, or some other aspect. Is the actual digital data the problem? Not likely, as the modulation schemes are complex and would appear as electrical "noise." Is the rapid-fire turn-on turn-off the problem? That is a possibility, as rapid electrical transitions are associated with the presence of many harmonic frequencies (whole number multiples of the fundamental frequency used), constituting "Wideband Emissions" discussed elsewhere on this site. These electrical transitions may also be available through the indoor power system in a fashion similar to the Turtle example up above. When one considers that the landscape future looks like a mesh of wireless meshes for the many utilities, the prospect of electrical "silence" becomes more and more elusive.
Should you wish to attempt to keep your home, neighborhood, or town AMR-free, then your only recourse may be your elected officials or the Boards that have jurisdiction over the various utilities. You can state your desire, or demand, to not have AMR installed, realizing that it will in the end cost you more to keep the human meter readers employed.