By Josh Rasin and Karen Herter
The Lawrence Berkeley National Laboratory Demand Response Research Center is sponsoring a research, development and demonstration project that will create a means for utilities to provide electricity pricing information over the internet and FM radio – simultaneously.
The standard is open source, so the signals can be received by any of a variety of existing mass market information and demand response devices. Device vendors are signing up to be included in the demonstration, which is due to be unveiled sometime this fall.
The planned system makes use of two open source data models – OpenADR and UMC – each using public communications channels to reach the intended targets.
The Open Automated Demand Response (OpenADR ) communication specification is an information model based on eXtensible Markup Language (XML), and uses the public internet as its communications channel. OpenADR transmits all signals over the internet through a Demand Response Automation Server (DRAS), using encrypted connections for privacy and security. As implied by the name, OpenADR is an open standard, which means that anyone can freely implement the standard without a license. Implemented correctly, the standard allows devices from various vendors to be interoperable.
OpenADR was developed by Lawrence Berkeley National Laboratory, and has been used since 2001 to send electricity pricing and event information to energy management control systems in commercial and industrial buildings. OpenADR is currently used by all of the California investor owned utilities (PG&E, SCE, and SDG&E) at over 200 facilities statewide to support critical peak pricing, demand bidding and capacity bidding programmes. Seattle City Light in Washington State is also getting their feet wet with OpenADR, with five test facilities currently using the protocol.
The Utility Message Channel (UMC) communication specification is a data model similar to OpenADR. UMC messages are broadcast over Radio Data System (RDS), an FMbased communications channel that can cost effectively transport digital information that is both human readable and machine actionable. For decades, RDS has been used primarily to display music and traffic information in automobiles. More recently, it has been used to send UMC demand response pricing and event information to thermostats in the residential and small commercial sectors.
The first objective of this study is to develop and demonstrate the capability to send a time varying price schedule – through the OpenADR web-based interface – that will ultimately reach a variety of information and demand response devices via internet and RDS. This will require a translation from OpenADR to UMC, i.e. a “bridging” client that maps the OpenADR data set designed for use on the internet into a UMC data set to be sent over the RDS communications channel.
Messages sent over the hybrid OpenADR-UMC system will be set up to target groups of ADR or RDS-ready devices using group codes that are specific to utilities, utility programmes and device types. Two device types are currently planned for the demonstration: those that can understand a full schedule of prices, and those that can understand price levels, e.g. low, medium, high or critical. Unique service codes will specify which types of messages a device can receive and act upon.
The study will culminate in a demonstration unit showing control of appliances and HVAC using a hybrid OpenADR-UMC notification system. The demonstration unit will contain an internet connected laptop and a portfolio of internet and RDS communicating devices, along with a miniature home containing controllable appliances. The intent of the display is for users to send pricing or event signals through the OpenADR user interface and watch in real time the response of the communicating devices and controlled appliances.
In large commercial and industrial operations Energy Management Control Systems (EMCS) are commonplace, and are easily set up to receive OpenADR notification of demand response prices and events. The response is then carried out according to the information received either automatically or by a human operator.
All devices slated for use in the demonstration are intended for use in the residential and small commercial sectors. Devices available for the home market are not as widespread, although their presence is growing. Communicating or “smart” thermostats are becoming more commonplace, and are expected to eventually replace the load control cycling mechanisms that have been used on air conditioners over the past several decades. To date, vendors who have confirmed inclusion in the demonstration include General Electric, EnergyHub, Residential Control Systems, and Entek. Several other manufacturers are currently evaluating whether they will be ready to participate in time.
Some of the organisations watching this project closely include the California Energy Commission and the California Independent System Operator (ISO), both of whom have expressed support for an open source, mass market broadcast of time varying retail electricity prices. A statewide system such as the one described here would encourage low cost implementation of dynamic rates, which would provide much needed system load leveling without the need for ISO system emergencies – currently the only way to invoke demand response programmes.
- Open Automated Demand Response Communications Specification (Version 1.0), Lawrence Berkeley National Laboratory and Akuacom, April 2009, CEC-500-2009-063
- Herter, Karen, Seth Wayland, Josh Rasin. 2009. Small Business Demand Response with Communicating Thermostats: SMUD’s Summer Solutions Research Pilot. California Energy Commission, PIER Building End-Use Energy Efficiency Program.