February 2, 2004
Berkeley Lab Research News
Multi-Building Internet Demand-Response Control System: the First Successful Test
Technology Will Help Prevent Blackouts and Electrical Grid Overloads
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BERKELEY, CAóResearchers at the Department of Energy's Lawrence Berkeley National Laboratory have completed the first successful test to evaluate automated demand response at five large building facilities. Demand-response technology manages electrical use in the buildings over the internet, whenever high prices, blackouts, or overloaded electrical demand threaten the power grid.

"This is the first test of fully automated demand response in multiple large buildings to reduce electricity consumption with two-way internet-based communications," said principal investigator Mary Ann Piette of Berkeley Lab's Environmental Energy Technologies Division.

To test demand response in large commercial and institutional buildings, researchers sent real-time signals and evaluated responses with no operator in the loop.

"We used a fictitious electricity price to trigger the demand-response event over the internet, which is an example of what might be used in the future; no one touched any control systems during our test," said Piette. "When an XML signal broadcast over the internet indicated that the price of electricity hit 30 cents per hour, the buildings automatically began to lower demand by reducing lights, air conditioning, and other activities. Two-way communications were used to observe that each site was listening to the price signal. When the internet indicated that the price had reached 75 cents an hour, the buildings automatically took additional preplanned actions to further reduce electrical demand."

Commenting on the test, California Energy Commissioner Arthur T. Rosenfeld said "The LBNL study complements current initiatives by the CEC and the CPUC"—the California Public Utilities Commission—"to institute dynamic pricing in California. LBNL's results are encouraging in that they indicate that large commercial buildings using off-the-shelf technology can automatically shed load in response to price signals."

XML stands for eXtensible Markup Language, which is used to improve the exchange of structured data over the web. It provides a common language for communicating with different energy management systems in the buildings.

The test, which was funded by the California Energy Commission's Public Interest Energy Research (PIER) Program, was conducted in five buildings: an Albertsons grocery store; a Bank of America office building; Roche Palo Alto, a biotechnology facility; a library at the University of California at Santa Barbara; and the Ronald V. Dellums Federal Building in Oakland. The effort, led by Piette, used server technology developed by Infotility, Inc. to manage the broadcast signal and acknowledge responses. Piette and her research team worked with facilities managers at the five locations to integrate the control software into their building control and energy information systems.

"A key feature of this test was gauging the capabilities of today's technology," said Piette. "The test incorporated methods to initiate fully automated demand-response control in different building types with different control systems from different vendors. We've demonstrated that many different types of systems can listen to a common XML signal and initiate coordinated load control using the internet."

The systems tested include Itron Enterprise Energy Management Suite at the UC Santa Barbara library; Webgen Intelligent Use of Energy at the Bank of America in Concord; Tridium Vykon Energy Systems at Roche Palo Alto; a web service with a custom BACnet Reader program and BACnet controller at the Federal Building in Oakland; and Engage Networks/eLutions at Albertsons in Oakland. The manufacturers of these systems received funding from the California Energy Commission's AB970 and SB5X Demand-Response programs to enhance control and internet connectivity features. All of these sites have state-of-the-art, web-based energy monitoring systems.

Berkeley Lab, working with Infotility, sent a continuous XML signal to the five facilities during a two-week period. On two occasions the signal indicated higher prices to initiate the automated load reduction. The demand response systems at each facility were programmed to accept XML signals. Facility managers decided which loads were reduced by the automated response system at each site. Berkeley Lab collected data on how the systems responded to that signal, and evaluated the response performance.

"Albertsons was interested in learning more about what our ability would be to curtail load based on pricing signals," said Glenn Barrett, a spokesman for the grocery chain. "We also wanted some insight into how those pricing signals would be sent and interact with our controls, preferably without human intervention."

Barret said, "We learned we do have the ability to react to changes in commodity pricing and make changes in our stores that will allow us to curtail load. It also lays the foundation for a web-enabled solution that could be applied to any store across the state of California."

What is Demand Response?

Demand response is the catchall term for giving energy customers the ability to lower their electric demand in response to dynamic energy prices or emergency curtailment requests.

"California is investigating 'dynamic pricing' tariffs as a sustainable strategy for mitigating electricity supply-demand imbalances that can result in high prices and forced outages," says Piette. "One form of these tariffs would offer rate discounts when system conditions are normal—most of the time—and charge higher rates, called critical peak prices, when the grid is approaching an overloaded state, or during wholesale price spikes."

The benefits of such a strategy are many. If a power plant or transmission line goes down, signals can quickly reduce power demand as well as the likelihood of a full-scale outage. Some experts on the electrical grid believe that a system with automatic demand response could have avoided the blackout in the eastern U.S. and Canada on August 14, 2003.

Dynamic rates can also signal to the market wholesale electricity costs, which tend to be highest when electricity demand is unusually high or when supply is unusually low. Current retail electricity rates don't reflect such unexpected changes in wholesale prices. Customers don't know when electricity is unusually expensive and therefore have no motivation or incentive to reduce demand during those times. For example, during a few critical days per year in California, usually the hottest days, wholesale price spikes can be 10 times the normal price or more.

Finally, customers on dynamic tariffs can reduce monthly bills by reducing usage during high-priced periods, or by shifting usage to low-priced periods.

Future research will include additional testing and analysis at these and other sites. Tests were conducted on a diverse set of buildings—an important feature of the project if demand response is to control a large fraction of the state's building stock someday. Eventually the majority of commercial buildings could be dynamically managed using these systems, reducing the likelihood of future blackouts.

Others who participated in the test include Berkeley Lab's Osman Sezgen, David Watson, and Naoya Motegi; Joseph Desmond and Nicholas Kardas of Infotility; Gaymond Yee of the California Institute for Energy Efficiency; and consultant Christine Shockman. Ron Hofmann, a consultant for the California Energy Commission, also participated.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California.