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The beginning of the direct consumption feedback wave

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6 May 2009 Update: For more information about meter interfaces and open-source energy management, visit The OpenAMR Project.

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February 2009 will go down in history as the month when the the average educated citizen noticed the smart grid movement. We have Google to thank for the immediate publicity in the form of their announcement about Google PowerMeter. We must not forget, though, about the host of smaller players working with Google (or independently) to bring marketable solutions to the hands of consumers. A good thing, because this is not a software problem that Google can fix with just clever computer code and a snazzy user interface. It is an economic and political problem, where the scale of deployment will be driven not by demand but by the government policy that has the power to influence demand.

Smart grid technology, in its Phase 1 form as direct consumption feedback, has huge potential in terms of energy efficiency. For an example of a device this provides direct consumption feedback, see Landis+Gyr's ecoMeter. But as cool as the technology is to those of us who get off on tracking kilowatt-hours, the average person may not really care. The potential lies, unfortunately, not in the immediate impact to consumption that will come about through availability of devices like the ecoMeter, but in the plethora of future possibilities it will expose to the early-adopters and innovators in the market. After all, if past research is any indication, we might reduce consumption by 4-15% in residences employing a consumption feedback device (source: California Information Display Pilot Technology Assessment). By some measures, that is a lot. By my measure, that is not nearly enough. But, realistically, it's about all we can hope for this year. And any gain is better than the alternative.

It is relatively easy to show a consumer how much power he is using once consumption information has been sussed out of the power line feeding the home. The Energy Detective has solved that problem using simple current probes attached to a home's electric panel. Black and Decker is marketing a device that monitors power consumption by counting the rotations of the spinning disc in your mechanical electric meter. (Review) Once these devices have access to near-real-time load information, they can employ a technique known as non-intrusive load monitoring (US Patent 4,858,141) to figure out how much power individual appliances are using. Very soon, Google will probably be doing the non-intrusive load monitoring (NILM) for us. Despite the obvious privacy issues, the combination of well-designed analytics software by Google and an inexpensive, easy-to-use electric meter "bridge" interface could present a very functional combination for getting direct consumption feedback into the hands of consumers.

But are The Energy Detective and the Black and Decker Power Monitor, priced at about $145 and $100 respectively, cheap and easy enough to appeal to the average consumer? I say no. The average consumer does not feel comfortable fiddling around inside a live 220 volt electrical panel to install The Energy Detective, not does he want to attach a Black and Decker sensor to the outside of his electric meter using a hose clamp. Both are sub-optimal solutions appropriate for geeks and early-adopters; neither solution will be revolutionary.

The better solution is to simply read the utility company's meter directly. A budget-conscious friend of mine with a drafty old house and a new heat pump tracks his power budget by going out to his meter once a day and noting down the readings with pencil and paper. What a pain. Enlightened utility companies have moved past such drudgery using automated meter reading (AMR) technologies that allow them to read, from a distance, digital radio signals sent out by a tiny, low-power radio embedded in the electric meter.

According to some sources, such radios are embedded in about 50% of electricity meters currently in use in the US. Yes, you heard that right: about 50% of the meters presently in-use support one-way digital wireless communication of real-time consumption information. Utility companies have been using this technology to save money for over a decade by reducing meter-reader staff, but the public didn't make much note of it.

Have you seen a meter reader poking around your house in the past few years? Probably not. But a white van with an antenna on the roof and a laptop computer in the passenger seat probably drives through your neighborhood once a month to get within range of your meter. The consumption signal is readily discernable from the street, if the right receiver is used.

Itron's AMR implementation, called ERT and rolled out in the early 1990s, dominates the AMR market. The technology, while proprietary and not openly documented, is not terribly complicated. What's more, the patent on the encoding and error correction technique (US Patent 4,799,059) expired a few years ago. The messages are not encrypted and use industry-standard transmission techniques.

In December, when I figured out that the Itron ERT messages could be read wirelessly, I set about designing and building my own prototype receiver. I'm a geek, and I thought perhaps I could shed some light on this relatively closed industry by figuring this out. I didn't know if anyone else had built an Itron ERT-compatible receiver/decoder, so I said, "Why not?"

I was able to build a working receiver/decoder in less than six weeks, learning all the necessary analog and digital electronic theory, as well as the embedded software design, along the way. (I must say that my background in computer science, software engineering, and amateur radio was helpful.) Using only "black box" techniques, I have been able to read my own meter wirelessly, getting the messages to my PC every few seconds. As I demonstrated that an ERT bridge can be built using very little hardware and relatively straightforward software, I began suspecting that is was only a matter of time before low-end (I'm guessing under $50 retail) receivers compatible with the Itron ERT protocol would begin coming onto the market. If they didn't, I was going to create one and fill the niche myself.

As if by cosmic connection, I discovered this week that just such a solution is under development at start-up Tendril Inc. in Boulder, Colorado. These guys have perfect timing, as they were able to hook up with Google and GE for a recent trip to pitch the Feds on direct consumption feedback and other advanced power management technology. Given the size of the existing Itron ERT deployment, Tendril's "ERT Bridge" device could sell like hotcakes, especially if funded by federal economic stimulus dollars. (And I suppose that leaves me only the option of leading an open-source ERT bridge initiative to ensure that Tendril keeps their prices at a reasonable level.)

Amidst this boom, who will benefit? Consumers, I hope. In the business arena, in the near term, the winner will be the company that successfully brings to market the missing link: the bridge to the huge, existing Itron ERT deployed base. Millions of meters, read by simple digital radio receivers, powering Google PowerMeter and desktop and mobile phone display widgets. That's the wave we will see swelling in 2009. I can't wait.

1 Comment

Hey -
I am very curious about the receiver circuit and protocol decoder that you have working. I have an iTron meter on my house and would like to duplicate this type of system. Would you be willing to share this information with me?

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