Smart Meters Save $$$ - Mechanical Engineers' Device Helps Electricity Conservation

January 1, 2007 — Smart meters are small computers that provide real-time information on how much electricity is being used by each customer and when, and can relay information back to the head office over the very same power lines they feed from. Smart meters can bill different rates depending overall grid usage, to encourage conservation. Users can program them to control appliances, for example running the dishwasher during off-peak hours, when rates are lower.

SAN FRANCISCO -- During the winter, we crank up the heat. During the summer, we turn up the air. And all the time we're eating up electricity. Now a new smart meter may help to save energy and save money.

Like most parents, finding ways to save is a priority for Trina Camping. But she thought saving on her electric bill was a lost cause. That is, until she saw the light and started using a SmartMeter.

"This is what makes a SmartMeter smart," Mechanical Engineer Tim Vahlstrom, tells DBIS. "It's mounted onto a typical electric meter."

Engineers at Pacific Gas and Electric in San Francisco are working on SmartMeters. They're mini computers that provide real-time information on how much electricity is being used by each customer and when.

"This utilizes a technology called 'Powerline Carrier.' So it puts the signal back on the lines that actually feed the Meter, back through the power lines, to the transformer, back all the way to the head office," Vahlstrom says.

Everything is done remotely. You can turn your air conditioning, heating and lights on at home -- even when you're on vacation.

Vahlstrom says, "I want my thermostat to raise temperature by five degrees or four degrees if the price of electricity gets above this level. Then automatically the thermostat we can send a command to do that."

Power outages can be detected immediately, and within seconds, power is back on. "It actually does these things remotely without a person on-site," Vahlstrom says.

Peak power hours are from 2 p.m. to 7 p.m. By running her dishwasher and other appliances later at night, the power company gives Camping and her family a discount.

"We've saved about $150 to $200," Camping says. It's the first step to saving electricity and saving money.

Minnesota, Arizona, Pennsylvania and Florida are already using the SmartMeters. Not all of the functions are available right now in every state, but will be soon.

BACKGROUND: Pacific Gas and Electric in California is installing Smart Meters in millions of homes: small computers that communicate with a utility's central data center, providing real-time information on how much electricity a customer is using, and when it is being used. These remotely-read meters can be linked to a variety of pricing and other options, and should help improve service and lower costs for consumers. Similar systems have been introduced in Minnesota, Pennsylvania and Florida.

SAVING MONEY: While there will be an initial small hike in electricity rates to pay for the $2 billion SmartMeter program, in the long term, potential savings could be considerable. The new "voluntary pricing plans" charge customers more for power used during peak periods (such as weekday afternoons) when supply is tight and prices are higher, and charge less at night on weekends, when demand and prices are lower. Users can plan their cost and energy usage accordingly. Power outages can be detected right away, and since everything is done remotely, there is no need for meter readings, or on-site connection or disconnection of service.

ON THE GRID: The nation's power grid boasts more than 6,000 inter-connected power generation stations. Power is sent around the country via half a million miles of bulk transmission lines carrying high voltage charges of electricity. From these lines, power is sent to regional and neighborhood substations, where the electricity is then stepped down from high voltage to a current suitable for use in homes and offices. The system has its advantages: distant stations can provide electricity to cities and towns that may have lost power. But unusually high or unbalanced demands for power -- especially those that develop suddenly -- can upset the smooth flow of electricity. This can cause a blackout in one section of a grid, or ripple through the entire grid, shutting down one section after another, making it difficult to restore power from neighboring stations.

AC/DC: There are two different kinds of electrical current: alternating current (AC) and direct current (DC). In direct current a steady stream of electrons flows continuously in only one direction, for example, from the negative to the positive terminal of a battery. Alternating current changes direction 50 or 60 times per second, oscillating up and down. Almost all of the electricity used in homes and businesses is alternating current. That's because it's easier to send AC over long distances without losing too much to leakage. Leakage is the result of friction as electricity travels along a wire over distance; some voltage loss inevitably occurs. AC can be converted much more easily to higher voltages, which are better able to overcome line resistance.

Note: This story and accompanying video were originally produced for the American Institute of Physics series Discoveries and Breakthroughs in Science by Ivanhoe Broadcast News and are protected by copyright law. All rights reserved.