Smart Meter, Smart Grid

April 9, 2012
Home-area networks have always seemed like a solution looking for a problem. Did I really need to adjust the thermostat from my iPhone?

Home-area networks have always seemed like a solution looking for a problem. Did I really need to adjust the thermostat from my iPhone? Did my refrigerator really have anything to say to my toaster? But things are quickly changing. With the advent of distributed generation in the form of rooftop solar, and an expected expansion of electric vehicle charging, the nation has become aware that the entire power system must become a lot smarter.

In the old days, it was easy. Electric utilities have a mandate to serve. If someone wants power, it’s the utility’s responsibility to supply it. Everybody pays. Utilities string more and larger wires and transformers to distribute the power. Generators are kept on standby just in case. Power created at central sources flows out through trunks and branches of the system. If something goes wrong, parts of the system can be disconnected and repaired safely.

It’s different if my neighbors and I have rooftop solar connected by inverters to the power lines, and a falling tree knocks down a pole. Now, it’s not so safe and easy to disconnect that power. If my neighbors discover what a great car my Chevy Volt is and everybody buys one, what happens when we all get home after work, plug-in our cars to recharge, turn on our air conditioners, and sit down in front of our big screen TVs? Better hope somebody has an old-fashioned land line, because we just blew out a distribution transformer.

It’s not sensible to just install more generation, bigger wires and transformers for these eventualities, when there is a more resource-efficient way, using the kind of digital computing power and communications now available. Enter the smart meter.

Of course, what the utilities have long wanted is infrastructure to eliminate the need for meter readers walking neighborhoods and braving dog bites. Smart, communicating meters can do that effortlessly. But a smart meter could also respond to trouble by disconnecting PV-equipped systems from the distribution system.

What about those electric vehicles? Here it gets tricky. Suppose Ann wants to go out tonight, and Phil is staying home. No problem. Ann’s car charges first, Phil’s later. What if everyone is going out? Does the price of power go up until someone finds another way to get there? Should Ann’s extra charge be applied as a credit to Phil’s bill? Maybe. Could smart meters figure out that people likes their homes cool in the afternoon and start the A/C early, both to pre-cooled homes and to avoid that extra load? Probably. All of which is why it is time for those smart meters to start playing a role. They can provide a valuable service, and save everyone money.

How can they save us money? There’s a huge cost involved with keeping redundant infrastructure ready for whatever loads show up. Some peak-load generators run less than 40 hours in a year, but must be maintained and kept ready for that eventuality. Same for all the copper in those wires. If we can manage the demand side by prioritizing and shifting loads, everyone can share in the savings from eliminating that infrastructure.

There are issues, of course. First and foremost, the smart system must withstand malicious software attacks. Remember the Stuxnet worm which wrecked Iran’s uranium-enriching centrifuges in 2010, by attacking the Siemens controllers? Consider the havoc of a similar attack on an electric system based on smart meters. Indeed, this is why smart meters installed in California have been only partly utilized.

The meters typically have two digital radios using the Zigbee system. One communicates with the utility, the second is intended to communicate with devices inside the house. Security concerns have kept the second radio turned off. The original software, referred to as Smart Energy Profile, or SEP 1.0, was found to be vulnerable to hacks. Developers have been working on a more secure version, but that’s been “a-few-months-away” for several years now. Some say the original meters may be unable to run the new software without modification.

Many people have concerns about high frequency radiation, but in the era of ubiquitous cell phones and household wifi routers, a transmitter with a power of 1 W operating only a few minutes daily may not be a valid cause for fear. Others are worried that Big Brother will enter through the power receptacles.

Of course, Big Brother is already monitoring cell phones and email, so why worry? And with appliances getting smarter every day, perhaps my refrigerator actually will have something to discuss with the toaster.

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