‘Smart’ sensors promise savings in electricity costs
Devices are examples of research developed under CITRIS’ auspices

By Diane Ainsworth, Public Affairs

Video 1: Berkeley Engineering Dean Richard Newton explains new sensors as "smaller than a penny" and "cheaper than a dollar." Video 2: Berkeley Professor Kris Pister displays sensors. Video 3: Dean Newton discusses potential to save $5-7 billion annually in California's energy costs. Using small sensors placed throughout a building, it is possible to monitor and control the amount of energy used to heat, cool and light the building. UC Berkeley Media Services videos and photo

updated 15 June 2001 | A network of tiny, wireless sensors capable of monitoring the lighting and temperature of a building has the potential to cut California energy costs by as much as $7 billion — and reduce the Berkeley campus energy bill by about $900,000 a year.

The campus could realize those savings if all of its 250-plus buildings were outfitted with the new sensors, a group of engineers, environmental experts and facilities managers predicted at a recent demonstration of the latest “smart” sensor technology to be installed in Cory Hall.

For the $100 apiece cost of manufacturing the matchbook-sized sensors today, the state’s annual electricity costs could be cut by $5 billion to $7 billion, said Richard Newton, dean of the College of Engineering. The sensor demonstration showed how new technologies developed under the auspices of Berkeley’s proposed Center for Information Technology Research in the Interest of Society could help solve societal problems, particularly the state’s energy crisis.

“Very, very small changes in our ability to monitor and control energy, and in how we consume it, can make dramatic changes in the cost to the state and, ultimately, in our ability to make it through these (black) outs,” Newton said. “It’s a very leveraged approach to energy management.”

For the demonstration, researchers tucked the diminutive sensors into the corners of offices, placed them along hallways and mounted them in conference rooms throughout the fourth and fifth floors of Berkeley’s main electrical engineering building, Cory Hall, to demonstrate how the network operates. Berkeley engineers and experts in the College of Environmental Design are working with campus facilities managers and industry partners to build and test the array of “smart dust motes,” which trimmed 2 megawatts (10 percent) off Cory Hall’s energy consumption during a 1.5-hour practice test of energy conservation in late May.

"We have two key new technologies,” Newton said. “One is on the hardware side: very small sensors that we think we can get down to the size of a penny. Imagine sticking a penny on the wall; having 50 of them that will all communicate with each other automatically, wirelessly, and form a network that would control conditions in a room or building.”

The other key technology development is software architecture — in this case a small platform with a tiny operating system that gives the sensors computing power and their own “smarts” — that allows technicians to monitor and control lighting and temperatures.

“Sensor networks are not a new idea, but the technology that is used today is very large and clunky, expensive, and difficult to deploy in large infrastructures like this one (Cory Hall),” Newton said. “There is no software architecture that is integrated and tied into the (energy distribution) network right now that allows the utilities people and those making policy decisions to manage the relationship very well.”

The new smart sensor information technology also packs the potential for myriad applications. Smart sensors can be designed to monitor all sorts of environmental conditions, such as traffic congestion, air pollution or magnetic fields; be used for disaster mitigation by monitoring the motion of buildings during an earthquake; monitor the pulse, blood pressure or movements of elderly people; and be used in new distance education networks.

“Our researchers have developed a prototype energy management technology that can eventually be deployed for less than a dollar per sensor,” Newton said, “but the goal of CITRIS research is to develop technologies like this that can readily be put to use to solve large-scale societal and quality-of-life problems.”

In preparation for the demonstration, Associate Professor Kris Pister and Professor Jan Rabaey, both of electrical engineering and computer sciences, installed more than 50 solar and battery-powered smart dust motes throughout Cory Hall, an older building that consumes large amounts of power — about $1 million worth each year. The sensors were outfitted with wireless radio transceivers and their own miniature operating systems to transmit continuous lighting and temperature readings to facilities managers controlling the building’s electricity usage.

“This web of sensors is providing huge reams of data about what’s actually happening at any moment,” Pister said. “We were able to drop 50,000 to 80,000 watts of power in this building during a practice trial. On a critical power shortage day in California, we could drop the load for one, two or three hours with no impact at all to people’s comfort. That’s as much electricity as it takes to power my street.”

Miniaturization is the centerpiece of Pister’s research. With the wireless sensors already developed, now it’s time to make the matchbox-sized sensors even smaller — about the size of a button — and reduce the cost of manufacturing them to less than $1 each. Researchers are only two to five years away from commercializing that miniature sensor technology, Pister said.

With proposed funding for CITRIS —slated to receive $33 million in matching state funds from next year’s budget — further miniaturization and mass production of the technology will be possible, dropping the cost of the sensors down to pennies, Pister said.

Buildings, which use about one-third of all energy consumed in the state and nation, could be outfitted with tens of thousands of tiny sensors, all tied into a central computer that would regulate energy usage, said Edward Arens, professor of architecture and director of Berkeley’s Center for the Built Environment. During peak hours of energy consumption, air conditioners, ventilating systems, lights and computer networks would be automatically shut off, then turned on again when the demand had subsided.

Once buildings have a bit of brains, Pister said, passive sensors will be designed to perform more intelligently. The next generation of smart dust motes could be sophisticated enough to cut power automatically to certain building systems during specific times of the day.

“We would see a savings of about $900,000 a year on the Berkeley campus if all of the buildings were outfitted with these sensor networks,” he said. “The network would pay for itself in a year.”