The Department of Energy has called the U.S. electrical power grid the largest machine on Earth. It has over 9,200 generating units that produce more than 1 million megawatts of electricity. And they're connected to a network with more than 300,000 miles of transmission lines. In 2003, the National Academy of Engineering identified electrification, made possible by the national power grid, as "the most significant engineering achievement of the 20th century."
The power grid differs from a computer network in one basic respect: A computer network can store data until it's needed. Electrical power must be used at very nearly the moment it's generated.
Unfortunately, the current grid is a one-way system, funneling electricity from big centralized power plants to workplaces and homes with no feedback. It is old, it breaks down frequently, and it wastes energy. It must work nearly perfectly all the time; otherwise, problems and defects tend to cascade. In the past 40 years, the grid has suffered five massive blackouts, with three of them occurring in just the past decade. Even worse, power companies often don't know that they've had a power outage until customers call to complain.
Because providers can't easily detect demand fluctuations, power plants have to run at full capacity all the time, most burning carbon-emitting fossil fuels. Between 5% and 10% of power is lost in transmission.
A smart grid would use digital technology for two-way communication between producers and consumers. It could address individual devices, enabling home appliances to use electricity only when it's abundant and inexpensive. Electricity managers could examine their systems, identify and avoid problems, and get information about blackouts and power quality in real time.
- Integrated communications for real-time information and control.
- Sensors and measurement technologies for monitoring and reporting line conditions.
- Advanced components, such as superconducting power cables.
- Control and monitoring methods that make it possible to solve problems quickly and accurately.
- Improved interfaces and decision-support tools.
A smart grid would save energy and emit less carbon. It would have intelligent, networked electric meters that could track electricity use and adjust rates and usage patterns automatically. It would make it easier to integrate alternative, intermittent power sources like wind and solar into the electrical supply. And it would have more-efficient, superconducting transmission lines to reduce losses.
A smart grid would let a community use local power when electricity wasn't available from outside sources. For example, if a community were disconnected from the grid, a home could use power from local rooftop solar cells or small hydroelectric and wind generators until the connection was re-established.
Several precursors to the smart grid are being piloted.
Boulder, Colo., is a testbed for smart-grid technology. About 14,000 homes there can check online to see how much power they're using, program appliances over the Web and choose their power sources. For example, they can set their dishwashers to run only when solar power is available. The local power utility, Xcel Energy Inc., can remotely turn down thermostats or shut off hot-water heaters in participating homes. The system is too expensive for general adoption now, but the Boulder pilot should help work out problems for future implementations.
And Google Inc. recently announced Google PowerMeter, a platform for home energy information. Selected employees are currently testing it, using home energy monitors to record power usage. A gadget on their iGoogle home pages shows how much energy they're using, with historical tracking and trend forecasting.
Kay is a Computerworld contributing writer in Worcester, Mass. You can contact him at firstname.lastname@example.org.
For a complete archive of QuickStudies, go tocomputerworld.com/quickstudies
This story, "The Smart Grid" was originally published by Computerworld.