Grid-Interop Forum 2007 103.106-1 Appliance Interface for Grid Responses Conrad Eustis Portland General Electric 121 SW Salmon Street Portland, OR 97204 conrad.eustis@pgn.com Gale Horst Whirlpool Corporation 750 Monte Road Benton Harbor, MI 49098 gale_horst@whirlpool.com Donald Hammerstrom Pacific Northwest National Laboratory 902 Battelle Blvd, MSIN K1-85 Richland, WA 99352 donald.hammerstrom@pnl.gov Keywords: Communication protocol, appliance control, demand response, interoperable devices, communications Abstract A successful, rapid integration of technologies from three different companies was achieved as part of the Grid Friendly™ Appliance Project. Therein, a simple but effective interface was defined between a vendor’s commercial energy management system control module, an experimental electronic sensor and controller, and a smart appliance. The interface permitted each entity to use its preferred, proprietary communications up to the interface without divulging any protected or sensitive attributes of the entity’s hardware, software, or communication protocols. Those who participated in this integration effort recognize the potential value of the interface as an interoperability model, which could be expanded and extended with participation and buy-in from a larger community of stakeholders. The result could become a universal interface for the communication of demand response objectives to appliances and other small loads. We focus here on the business and marketing challenges. 1. SIMPLE, APPLIANCE CONTROL INTERFACE DEMONSTRATED The authors began their collaboration during the Grid Friendly Appliance Project [1]. This project modified residential hot water heaters and clothes dryers to be responsive to the Grid Friendly appliance controller. Pacific Northwest National Laboratory (PNNL) designed the controller to reside in an appliance and monitor system frequency. During an underfrequency event the controller signaled the appliance to shed load. A fourth collaborator, Invensys Controls, won a competitive project solicitation to supply persistent monitoring of the controllers and appliances via components of their GoodWatts™ energy management system. Practical limitations due to manufacturing constraints and safety issues forced the project to adopt a limited integration with the controller external to the appliance. However this change created the seed for the new approaches discussed in this paper. With the controller external to the appliance, the next critical step was to meld the communications between the dryer, controller, and monitoring system. Understandably, both Whirlpool and Invensys use proprietary serial communications on their respective products. To also ease the testing and debugging phase, a decision was made to reduce communication at the interface down to only three Boolean signals that could be communicated on dedicated wires indicating the following messages: GFA - An underfrequency event has been recognized by the Grid Friendly controller. Appliances should immediately reduce their power consumption. En - This signal asks the appliances to respond to a traditional direct load control program. The water heater turns off. The dryer beeps, displays “En”, and requires the consumer to acknowledge if they want to override this request and initiate a drying cycle. Pr – This signal indicates that a high price condition is in effect. The appliance should advise its owner to defer energy consumption, or to respond in a way appropriate for the particular appliance receiving the signal. The project dryer will beep and display “Pr” on its panel. While remarkably simplistic, these basic signals captured these authors’ imaginations and demonstrated how a simple appliance interface can fulfill the basic needs for Demand Response (DR). 1.1. New Approach for Responsive Appliance Loads Evaluation of the project with an eye towards commercialization led to the following potentially economical demand response opportunity. The basic solution would be a standard that defines a single physical socket to be located on all major appliances. The pins of the socket provide power to a communication device that the appliance owner would “plug in” at a later date. The pins relay basic Boolean logic signals between the appliance and device, which may then communicate externally via any chosen medium and protocol. Optionally, a serial protocol