Is your refrigerator the solution for greener energy? Not entirely, but giving your fridge the ability to think for itself is an excellent first step when it comes to preventing future power blackouts, according to results from a pilot project led by the Department of Energy and Pacific Northwest National Laboratory.
In the project, called GridWise, everyday appliances like washers and dryers were equipped with small electronic circuit boards and installed in more than 200 homes in Washington and Oregon. These circuit boards are programmed to detect changes in the alternating-current frequency coming into the appliance. When the device senses a lower frequency, signaling less available electricity on the grid, it reacts by turning off certain functions of the appliance: a dryer might keep tumbling clothes but switch the heating coil off; a fridge light could stay on while the cooling motor took a break. These responses happen in less than half a second, last for only around 10 seconds, and are nearly undetectable by homeowners.
The autonomous appliance reaction lowers the demand on the grid system for about 5minutes, allowing secondary response systems to kick in. “Think of your fridge or stove as an initial shock absorber,” says Rob Pratt program manager for the GridWise program.
While powering down the appliances in one home would not do much, if every home in New York or Los Angeles were equipped with the GridWise system, it could be enough prevent serious blackouts like the one in 2003 that paralyzed the Northeast, says Pratt. The key is that the circuit board can react to conditions on the grid instantaneously—something humans cannot do.
Along with clever appliances, some homes in the GridWise project received computer systems to monitor the real-time price of power and limit consumption when the price spiked. Pratt describes the system as a mini energy marketplace in the home that works as a second buffer when the grid is overloaded. When demand for energy is high, he notes, so is the price. Homeowners can program their thermostats, for instance, to automatically take a break if the price of energy skyrockets. The real-time price of electricity is updated and processed in homes every five minutes.
In the case of an impending blackout, a dryer and refrigerator respond first, quickly shutting off and temporarily decreasing power consumption. Then the second-tier price-driven system kicks in. That allows time for power suppliers to react to the overload by turning on backup generators or redistributing power throughout the grid—the final step in the process.
Fewer blackouts and money savings aside, equipping homes with smart energy systems could allow electric companies to switch to using more energy from renewable sources like wind and solar. Today, wind and solar power are considered too unreliable to be used on a mass scale, unable to supply energy when the sunsets or the wind stops. In a price-responsive system, however, rainy days could mean slightly higher energy prices, which could cause homeowners to scale back on energy consumption, says Ron Ambrosio of IBM *Research, a branch of the company researching new energy strategies
There are no technical hurdles; Ambrosio says policy and market acceptance are the biggest roadblocks to adoption of smart appliances. His estimation for widespread use of this type of energy system: 10 to 15 years, if manufacturers,consumers, and governments get behind the idea.
*Correction February 20, 2008: this originally stated IBM Energy.