Ready or not, here comes smart metering

The Talon e-meter display is one interpretation of how to produce smart grid-information in a consumer-friendly manner.

Get ready for a new acronym. Advanced metering infrastructure (AMI) is about to enter the mainstream lexicon of energy efficiency. Electric utilities worldwide are jumping on the bandwagon for AMI, which refers to the vast network of smart electric meters needed to let smart utility grids reconfigure their loads and power sources as conditions dictate.

Power utilities plan to add about 100 million smart meters to buildings, homes, and all manner of appliances. No surprise, then, that AMI has gotten the attention of the electronics industry. Industry heavyweights that include Intel and GE are involved with the AMI concept. Part of the attraction is that chips targeting AMI won't just go into electric meters. They will also get installed in smart sub-stations, plug-in hybrid vehicles, in-home displays, and all manner of renewable energy systems. Nor are AMI chips strictly for metering electricity. They can also meter gas, water and heat.

Despite all of the interest in the AMI, there is a bit of uncertainty about just how successful smart metering will be. Energy experts point out there must be incentives for consumers and businesses to accept a new metering concept. Those incentives are still murky.

Lorie Wigle, general manager of Intel's eco-technology program office, points out another challenge for both utilities and semiconductor IC makers: How to reconcile utility grid equipment life with semiconductor cycles. Such equipment is designed to last 10 to 20 years. This makes it difficult for smart meters to quickly incorporate new generations of semiconductor chips that generally emerge every one two years.

Nevertheless, there's wide agreement that the AMI concept is here to stay. Now the involved parties have begun working out how to take the first baby steps in getting it implemented.

Smart metering chips like Freescale Semiconductor’s MCF51EM128/256 employ 32- bit processors, in this case the ColdFire V1 core, more to handle communication and management tasks rather than do relatively straightforward power line measurements.

AMI smart metering incorporates the idea of utility meters at every home and office building that collect information about the load demand. The meters would pass such information back to data aggregator nodes on the grid that would have their own smart-metering functions to analyze, among other things, where demand is most concentrated. Aggregators would also predict short-term demand based on historical patterns. Aggregators would, in turn, interact with smart-metering network sensors called phasor-measurement units. PMUs constantly sample the voltage, current, and frequency of power flowing on the grid. Using embedded GPS modules to synchronize their measurements, PMUs and data aggregators will deliver real-time analyses of electric grid conditions.

Simple metering functions don't take much more than an 8-bit processor, but designs are moving to 32-bit systems because of the communication protocols involved in sending demand data back and forth. Also, developers of AMI gear tend to be concerned about building in more accuracy for readings than has been available with the familiar electromechanical meters of today. The international standard has become class 0.5 — for readings of 99.5% accuracy — compared with old electromechanical units giving class 2 or 3 at best.