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Ask Slashdot: Are Smart Meters Safe?
An anonymous reader writes "There is a lot of controversy and a big hullabaloo about Southern California Edison and various other utilities around the country installing smart meters at residential homes. Various action groups claim that these smart meters transmit an unsafe amount of RF and that they are an invasion of privacy. The information out there seems rather spotty and inconsistent — what do you engineers out there think? Are these things potentially harmful? Are they an invasion of privacy?"
Don't forget the biggest source of hazardous radiation: the sun.
I think the idea is that, with a smart meter, the utility can tell when you consume that power, and what the incremental steps are. For example, you could probably figure out when the occupants wake up, go to bed, turn on the computer, turn on the TV, turn on your marijuana grow lights, etc. The article lists some other things such as "whether someone uses a specific medical device or baby monitor" that I find somewhat dubious, but within the realm of possibility, especially if they have a particularly unique way of using power (the wattage used, and the duty cycle, for example - more likely with a medical device than a baby monitor, though).
That said, it's not a reason to not adopt the technology, which can bring a wide variety of benefits, as you mention. It *is* a reason to pass legislation to control who can access that data and under what circumstances, if you feel that it is likely to be mishandled.
Finally, after years of lurking, a subject I can speak with authority on.
I actually got to speak to a Georgia House committee on the subject of smart meters, since I work for one of the major manufacturers. Here are some of the things I told them...
Our meters use licensed 900Mhz FSK (not spread spectrum) bursts. An average electric meter transmits 6 times a day with 1 watt EIRP (off a PCB antenna in the meter), in bursts of about 180ms. Total on-air time is nominally 1 second per meter per day.
As for privacy, we use symmetric AES-256 encryption with per-meter keys for both uplink and downlink to the meters (our meters are twoway-capable). Keys are rotated generally every three months (yes, imagine rotating 4+ million encryption keys every few months, over a system with an aggregate bandwidth of about 12kb/s).
We sell a "remote-disconnect" option in our meters, but it's expensive and only used by electric companies in limited situations. While we can trigger a remote disconnect, in the interest of safety we cannot re-energize a meter without a very complicated dance. Instead, we send an arm-for-reengize command, and then tell the consumer to take their TV remote control outside and point it at the meter and hit the "POWER" button. An IR receiver in the meter face then causes the meter to re-energize.
One of the big complaints (after they get past the RF) of the anti-smart meter groups is the use of "dirty switching power supplies". According to the anti-smart-meter web sites, these switching power supplies cause surges on the AC mains, which somehow increase cancer risks up to 13 times. The power supplies in our meters are actually certified under 3 different FCC type ratings, and are somewhere north of 95% efficient buck-boost supplies. Since the load of the metrology and RF boards in the meter is minuscule, smart meters generally only draw milliwatts while running, and the chances of inducing large spikes onto the mains is non-existent.
I got to meet some of the people behind the anti-smart-meter campaigns. For the most part, they're nice elderly ladies who get their view of the world from Pat Robertson and Fox news. They crave some cause in their life, are experiencing health issues generally related to aging and unhealthy choices, and find any new technology (especially hard-to-understand, mandatory-use technology like smart meters) scary and use it as a good scapegoat for their health worries. Everyone here realizes that a web page is the ultimate printing press, and with enough Googling you can find some "expert" pushing some kind of "science" to support pretty much any view you wish to cling to. It's embarrassingly easy to put together a semi-literate sounding alarmist web page backed up by flaky pseudo-science and gather like-minded people to your way of thinking.
Bottom line is, as an electrical engineer, an extra class amateur radio operator, and a father, there are about a million things my kids run across every day that are more damaging or dangerous than smart meters. Most of those are naturally occurring (sunlight kills more people in a year via skin cancer than every smart meter I've ever played a part in will kill in a thousand years). If you need something to stress about or blame your poor health or weird medical condition on, please find a better scapegoat than smart meters.
While it's definitely the power company's right to know how much power I'm using, and even to know in aggregate how much peak versus non-peak power I'm using, but they really shouldn't need to know hour by hour or minute by minute (or even day by day) how much power I'm using.
Actually, this is the entire idea behind the smart grid. The data is not for them to know how much to generate - as you pointed out, they already know that. The idea is to charge you more for the electricity that costs them more to generate. Not all power is generated equally cheaply. On a hot day with lots of A/C usage, they have to bring emergency generators on line. These burn very expensive fuels, such as natural gas, and cost them 10 times as much as the electricity generated by the much cheaper coal fired plants. They want to bill you a lot more for the times they're forced to bring those extra generators on line, because if they charge you more, you might change your mind about consuming electricity that's so expensive to produce. So the smart grid will use consumer demand to reduce their need to supply.
The smart meter's job is two-fold. One task is to record your usage depending on the rate. The other is to transmit the rates to your smart household appliances. This would be messages like "the current non-peak rate is $0.16/kWh" or "the peak rate from 4:00 PM to 8:00 PM will be $3.25/kWh." If you have smart appliances that can read these messages, they can make their own decisions. You might configure your clothes dryer to run only when electricity is cheaper then $0.50/kWh, for example, meaning it would shut itself off during the really expensive peaks. Or you might configure your water heater to hold 140 degrees at $0.35/kWh rates, but 110 degrees at rates above that. This would give you the ability to make your own choices about placing peak demands on the power grid. You would think about if you really need 50 gallons of 140 degree hot water at 5:00 in the afternoon if it's going to cost you $7.00 extra per day.
The idea is simple: get people to cooperate to consume less energy. They've proven they won't do it for the environment, but they will do it for money.
John