IEEE-USA Home
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.