PROBLEM: Can we reduce power consumption without compromising our quality of life?
When ORNL scientist Jeff Christian declared in 2004 that houses could be designed to produce enough energy to pay for the power they consume, he had a lot of people shaking their heads in disbelief. Now that a growing number of zero-energy houses has sprung up in and around Oak Ridge, the same people are nodding their heads—this time in agreement.
The growing acceptance of zero-energy housing has inspired Christian to extend to the broader market the reach of both zero-energy homes and the technologies that enable these super-efficient houses.
A combination of new technologies, new habits and new policies will be required to make Christian's vision a reality. Consumers will need to be convinced to pay greater attention to their electricity consumption. Likewise, a commitment will be necessary from utilities to making smart grid capabilities available to consumers.
On the technology front, one of the most promising tools for reigning in out-of-control miscellaneous electrical use in homes is the home automation system. Many homeowners are surprised to learn that zero-energy houses are not solely dependent upon solar panels, high-tech gadgets and cutting-edge building techniques. The success of low-energy homes is made possible when people understand how and why they use energy. Researchers have found that the power required to heat, cool and provide hot water for most households accounts for only about one-half of energy consumption. The remaining 50 percent is used for a host of smaller activities, such as washing clothes, watching television and lighting rooms. Both halves of the energy equation can get a significant efficiency boost from the use of relatively simple home automation systems.
Increasingly common, these systems provide a communication link between the household electrical system and the utility grid. Through this link, consumers have access to a detailed and real-time breakdown of how much electricity they are using for specific appliances at specific times. Equipped for the first time with this information, consumers can begin to tailor their daily habits, and their energy consumption, to both their needs and their budgets.
ORNL researchers are working on the next generation of household appliances, which will include the capability to receive pricing information from the grid, as well as alerts about when electrical demand is expected to be particularly high or low. Christian's team is partnering with General Electric, Whirlpool, and the Tennessee Valley Authority to install this new capability into their test houses—Habitat for Humanity homes occupied by families—with the eventual goal of showcasing the technologies in larger, high-performance homes.
"Consumer behavior has a major effect on power consumption," Christian says. "Utilities understand that, so they are making a substantial investment to install 'smart' meters in residential areas to enable automation systems to communicate with the utility."
One of the key drivers behind the move to smart meters is the adoption by many utilities of time-of-day pricing for electricity—that is, charging more for power during peak use hours and less during hours when the demand is low. "For example," Christian says, "in California the nighttime rate might be five cents per kilowatt hour, but in the late afternoon when it's really hot and people are demanding a lot of air conditioning, the peak rate might be as much as a dollar per kilowatt hour."
On the most basic level, home automation systems can save energy by using sensors to determine when people are present and then turning lights and televisions off when no one is in the room. With the latest technologies, consumers can go a step further and allow the utility company to control the power consumption of their major appliances.
"For example," Christian says, "with a home automation system, families can shut down their hot water heater for an hour or two during parts of the day when it's normally not being used. Consumers might choose to let the utility choose these times or choose the times themselves. Similar technologies could also enable consumers to set their dishwasher or washing machine to start operating when electricity is cheapest. For instance, the dishwasher could be loaded after supper but be instructed not to start operating until 10:00 at night, when energy rates are lower—or the consumer might instead let the utility determine the most economical time to start.
"Giving the smart grid control of certain appliance functions has essentially zero impact on homeowners. The new technologies literally do not require them to do anything," Christian says. "However, people who want to adjust their behavior and control the appliances themselves can take even greater advantage of this system."
Christian points out that widespread use of new grid technologies would dramatically decrease the peak demand for power. This new aspect of energy conservation is an attractive alternative to building new power plants to support ever-increasing peak power demands. Confronted with the financial and political costs of building additional power plants, Christian says utilities are faced with the policy decision of whether it is better to take advantage of emerging smart grid technology than it is to add additional capacity to the grid. "If we can get a lot of people to participate, the potential for saving energy and saving money is huge."
When Christian says "lots of people," he means lots of people. The demonstration project he is currently pitching to utility companies around the country would involve equipping 200,000 homes with "smart" meters. Ideally, these would be zero-energy homes in order to have the greatest long-term impact on power consumption. "It really comes down to the electric utilities enabling consumers to take advantage of this technology," he says. "We can talk all day about fancy controls and fancy appliances, but the infrastructure has to be there first."
For example," Christian says, "in California, the utilities are making the investment to install thousands of meters every day." Building codes that recognize the benefits of this technology are being adopted, as well. "In Boulder, Colorado, the codes are graduated," he says. "If you want to build a house that is 5000 square feet or larger, then it must be a zero-energy house. If the new house is 4000 square feet, it must be a very efficient house, and so on. Even the smallest houses need to meet Energy Star standards that are established by the U.S. Environmental Protection Agency and the U.S. Department of Energy."
"I'm also encouraged by the government's plans to invest in upgrading the country's electric power infrastructure using smart grid technology," Christian says. "I hope the result has an impact on our lifestyle as big as the construction of the Interstate Highway System 50 years ago.
"Christian acknowledges that the impact of any technology depends ultimately on whether consumers embrace it. "The issues of foreign oil dependence and climate change all come down to choices that individuals make," Christian says. "Zero-energy homes, smart grid technology, and home automation systems can enable consumers to reduce their energy expenditures without impacting their comfort or their lifestyles. This particular technology enables the customer to be part of the solution, rather than just complaining about the shortcomings of conventional power plants. Until recently, all we could do was buy or not buy power. In the world of tomorrow, we will become part of the process."
Web site provided by Oak Ridge National Laboratory's Communications and External Relations