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Grid Friendly

One way consumers might soon get the best prices for power-while at the same time reducing the strain on the grid-is by strategically timing when they buy electricity. Some large companies have been doing this in a rather crude way for years. A utility might offer them cheaper rates if they will agree to having their power turned off during times of peak demand. A company that can shut down operations for a few hours a few times a year can get a big break on its electric bill and can help utilities avoid overloading the grid. Similarly, a number of utilities have voluntary programs that give residential consumers a price break in exchange for installing energy-saving controls on their air-conditioning systems and water heaters. At peak hours, the utility sends a signal wirelessly or via the power lines that changes the thermostat setting on air conditioners or shuts down water heaters for a while.

Both the commercial and the residential programs are effective in their limited goals-helping utilities pull back from the brink when they near capacity. But neither explicitly involves the consumer in the decision to cut back on demand, says Steve Hauser, an energy systems expert at Pacific Northwest National Laboratory in Richland, WA. And if electricity is ever to become a true commodity whose price is set by the interplay of supply and demand, the demand will need to be determined by millions of individual decisions made around the grid.

To that end, Hauser’s team is developing dishwashers, refrigerators, air conditioners and other appliances that turn themselves off for brief periods of time when they sense it will help the grid. The “grid-friendly” appliances contain a device that a user can program so that shutoffs can be overridden at times when an appliance’s performance is critical. In times when the user’s needs are more flexible, however, the device can monitor the quality of the electricity flowing from the socket, detecting changes that indicate that the region of the grid is in danger of a blackout. The devices work because disturbances to the grid, like spikes in demand that outpace supply, can make the voltage level and the frequency of the current’s alternation deviate from their normal values. “If the frequency or the voltage started to shift, the appliance would drop off line for some period of time to allow the grid to stabilize,” says Hauser. Customers, he suggests, could get a rebate or a credit each time an appliance tripped off line. Of course, the grid won’t be saved by one or two dishwashers shutting down in a crisis, but Hauser envisions a time-perhaps as soon as three to five years from now-when a significant percentage of appliances sold are grid friendly.

One advantage of Hauser’s technique is that it does not depend upon providing special information to the appliances-all they need to know can be found in the current from the outlet. But ultimately, Hauser says, “we would like price signals to be sent down the line and have appliances respond to the price.” There is widespread agreement among power industry experts that utilities will eventually need to move to “real-time pricing,” charging more for electricity at peak times and less during periods of low demand to encourage their customers to move some of their use from peak to off-peak hours. Indeed, Washington State’s Puget Sound Energy is already charging homeowners different rates at different times-most on weekday mornings and evenings, less during the day, and least at night and on weekends. The utility hopes its customers will respond by, say, waiting until after 9 p.m. to run the dishwasher or washing machine.

But ideally, says Karl Stahlkopf, vice president of power delivery at the Palo Alto, CA-based Electric Power Research Institute, utilities would be able to vary pricing hourly or even minute by minute, sending real-time prices to smart appliances that can modify their activities automatically. Air-conditioning systems, for instance, might crank their thermostats up a couple of degrees when energy prices peak. Eventually, appliances might even send information back to the grid about how much electricity they expect to need in coming hours and how much they would be willing to pay for it.

Just how appliances would communicate with the grid is anybody’s guess, says Hauser: “It’s like trying to predict in 1985 where the Internet was going.” Researchers have suggested using phone lines, the Internet and satellite communications, among others. Some are even looking into transmitting the information along with the electricity, so an appliance would not need a separate hookup to keep abreast of fluctuating prices. But regardless of how the technical problem is solved, it’s clear that real-time pricing and communicative appliances could go a long way to solving both consumers’ and utilities’ woes.

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