Smart meters could yield household energy savings

They provide real-time updates on the cost of running a house full of gadgets

For years, consumers have gauged their electricity usage through their monthly bills. Given that a bill arrives days or weeks after the billing period, it isn't a very efficient tool for cutting household electricity use. But a new breed of meter is changing that and can provide real-time updates that offer an instant indication of the cost of running a house full of gadgets.

President Barack Obama has pledged to put 40 million of the so-called smart meters into American homes as part of the economic stimulus package -- but in some European homes, the devices are already a helping users to save money.

At the CeBIT IT fair last week, German utility Energie Baden-Württemberg (EnBW) was demonstrating its smart meter, which has been available to customers since late last year.

The meter is available to homes for about $6.34 per month, but customers who use its many reporting features can typically save more than that amount in electricity usage, said Jörn Kröpelin, from the company's strategic product department.

The meter itself has a simple LCD showing current consumption, so subscribers need a PC to take advantage of its benefits.

There are two interfaces available. A Web-based interface provides reports down to 15-minute intervals via EnBW's server. It includes historical data as well, so users can compare weekly or year-to-year usage, for example. A recently added function lets users compare their usage to that of an average home.

The meter reports to EnBW once every 15 minutes via a home's broadband connection, and within 30 minutes that information is available online through the Web site.

A second option provides real-time data directly from the meter, as long as the PC is on the same network. Through this, users can instantly see energy use and analyze the power consumption and cost of running individual gadgets.

Energy usage is plotted on a graph through which it's possible to isolate spikes, such as when a TV is switched on, and then calculate how much it costs to run the appliance for a particular amount of time. You can also plug in a usage scenario -- such as two hours per day every day -- to see how much you will spend annually to watch TV.

During a demo at CeBIT, the meter was hooked up to an espresso maker. After the appliance made a single cup, the meter calculated the annual running cost to be around $1.90, assuming four cups per day.

Kröpelin is among the meter's users.

"I was surprised by how much energy was used, even when I tried to switch everything off," he said. After cutting power to all the obvious appliances and switching off lights, the meter was still registering energy usage -- the result of various sensors and adapters around the home that did unseen and forgotten tasks. These added up to about 200 watts of constant energy use.

The next phase for the technology involves getting the meters to communicate directly with gadgets. Initially, this will likely work by plugging in appliances through adapters that can talk to the meter, but the feature could eventually work via products that have embedded intelligence.

Copyright © 2009 IDG Communications, Inc.

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