Part 1: Automated Demand Response a Better Way to Shave Peak Load
Automated Demand Response a Better Way to Shave Peak Load
By Roger Levy, Mary Ann Piette and Sila Kiliccote - January 2012 - Power & Communication
The California energy crisis of the late 1990s exposed broad weaknesses in existing utility demand-response (DR) capabilities. DR is a general term that encompasses actions by utility customers to reduce, shift or otherwise reschedule operations or end-uses in response to price, reliability, or event signals provided by utilities. DR is an increasingly important option for better managing utility system resources and customer costs. It offers a tool to address issues as diverse as peak energy costs, grid reliability and the emerging need to integrate more carbon-friendly renewable energy sources into the grid.
But DR programs have had many shortcomings. Issues included lack of availability and reliable performance, utility control strategies that often conflicted with occupant comfort and business operating requirements, and incompatibilities with existing building energy management systems. Utility-provided control switches often had limited functionality, and event notification for commercial buildings often required building operators to be present, to acknowledge signals, and to manually manage response settings.
OpenADR — the Open Automated Demand Response information exchange specification or data model — was developed to reduce the cost, expand the availability, and improve the effectiveness and value of DR. OpenADR redefines conventional DR to make it more scalable and flexible. OpenADR also transfers decision making and control from the utility to the customer and integrates DR with existing building energy management and control systems. OpenADR is on track to become a national standard, which will further reduce costs and expand support among energy service providers and building system and controls vendors.
What is Auto-DR?
Auto-DR (short for automated demand response) refers to specific DR implementation options using the OpenADR specification. Auto-DR uses communication infrastructures, based on open standards (e.g. Internet Protocol), to manage and curtail loads automatically and in real-time in response to price and reliability triggers. It enables interoperability among utility and customer systems. The OpenADR specification is a flexible data model designed to facilitate common information exchange between a utility or Independent System Operator (ISO) and its customers.
With Auto-DR, price and reliability signals are communicated directly to existing energy management and controls systems or end-use equipment controllers. Facility managers develop pre-determined DR strategies based on an energy audit or building commissioning. These are automatically activated in response to price and reliability events. This approach allows facility managers to design response strategies that are consistent with business operations, tenant comfort and lease requirements.
Linking event signals to existing energy management systems provides facility managers with control and flexibility to develop more sophisticated response strategies encompassing a range of loads. While Auto-DR enables facility managers to opt-out of any event, the machine-to-machine automated approach eliminates the need to curtail loads manually.
AutoDR architecture consists of two major elements. The OpenADR Server provides price, reliability and event signals to an OpenADR client at each site. OpenADR servers are typically established by utility companies, independent system operators or regional transmission organizations. OpenADR servers may also be used by aggregators or energy management service providers.
OpenADR clients are typically implemented as integrated Web services software in building energy management or controls systems. Legacy systems that don't have or can't accommodate integrated Web services can be retrofitted with a dry-contact relay to receive Auto-DR signals.
Unlike conventional utility DR programs that communicate directly to building controls (utility-to-customer), OpenADR clients reverse the communication flow by "listening" continuously (customer-to-utility) for DR signals. This approach preserves security by eliminating the need for utility or other provider DR signals to breach customer firewalls. Automation signals received through the OpenADR client can then be linked to existing pre-programmed demand response strategies independent of control network protocols such as BACnet, Modbus, or others.