Challenges of Demand Response and Distributed Generation by Chris Trayhorn, Publisher of mThink Blue Book, May 14, 2007 Project Introduction and Motivation Electricity system challenges have emerged in Washington’s Olympic Peninsula that make it an ideal laboratory for advanced intelligent utility network (IUN) experiments. The peninsula’s transmission feed is approaching capacity as a result of population growth, but there are significant concerns over siting additional transmission or central generation assets there due to the ecologically sensitive nature of the Olympic National Forest, which comprises much of the northern portion of the peninsula. In 2001, in response to that situation, Bonneville Power Administration (BPA) began their Non-Wires Solutions program of demand response (DR) and distributed generation (DG) experiments and pilots with the goal of minimizing the environmental impact of new transmission and generation construction. The Pacific Northwest GridWise™ Testbed program, part of the Department of Energy’s GridWise™ initiative, was established in 2005 to coordinate technology projects supporting the GridWise™ vision of a transactive electric infrastructure leveraging advances in information technology and communications. The goals of GridWise™ and the challenges faced by BPA led to the creation of the Olympic Peninsula Project as part of the Testbed program. This project combines DR and DG control, using a real-time retail market clearing mechanism to determine the optimal balance of DR and DG dispatch in response to the current state of the system. The yearlong Olympic Peninsula Project, which concluded in March 2007, was a partnership involving a number of organizations: Pacific Northwest National Laboratory (PNNL), IBM Research, Bonneville Power Administration, Invensys Controls and several public and private utilities in the region. PNNL, working with BPA, defined the project and acted as the overall project manager. IBM Research was responsible for the system integration of the various components with the market clearing system developed by PNNL. Invensys Controls provided the residential equipment, including communicating meters, programmable thermostats, load control modules for water heaters and broadband gateways for communication. Design of the Experiment – Participants and Structure The Olympic Peninsula Project involves about 120 residential customers and several commercial/industrial customers. The residential customers are divided into several contract types and a small control group. The contract types are fixed price, time of use/critical peak price (TOU/CPP) and real-time price (RTP). One of the goals of the project is to compare the performance of the three contract types, with particular emphasis on the RTP versus TOU/CPP comparison. The hypothesis being tested is that a properly designed and implemented RTP system will be more effective at managing Distributed Energy Resources (DER) such as DR and DG than a TOU/CPP system. Rather than work through the process of establishing experimental tariffs for the residential participants, PNNL implemented a shadow billing system with an online payment portal. Participants receive their normal utility bill based on actual consumption, and pay it as they ordinarily would. They receive an additional online bill for the experiment that represents their consumption from a virtual distribution feeder. That bill is paid via the online portal using funds seeded into an account at the start of each quarter, so customers experience no additional out-of-pocket expense (part of the project budget was reserved for this purpose). The amount of funds that are seeded is based on historical consumption for each customer. To give the experiment some level of real-world motivation and benefit in exchange for being responsive to critical situations or high prices, PNNL refunds any balance remaining at the end of each quarter back to the residential customer. Therefore, the more aggressively a customer responds, the larger his refund check will be. The experiment has been designed to allow the most aggressive participants to receive on the order of $150 – roughly what it might cost to take a family out to dinner, for example. The virtual distribution feeder is implemented with feeder modeling software at PNNL using the real consumption information being collected. This allows all the participants to appear as if they’re on the same feeder, and that feeder can be artificially constrained to create critical situations as part of the experiment. For the residential customers, the DR assets are the heating and cooling systems and the water heaters. The physical control components in the homes have been provided by Invensys Controls, and, in the case of the TOU/CPP contract homes, the Invensys GoodWatts pilot system is being used to implement the control management. Homeowners can set up occupancy profiles and timeof- day schedules based on the predetermined time-of-use tariffs. Critical peak price events are scheduled as part of the experiments based on expected constraint times. Fixed-price contract homes do not have any DR automation, but homeowners do have access to the same Web portal as the TOU/CPP and RTP contract homeowners, showing up-to-date consumption information. Their equipment also has the ability to help them manage reduction of electricity consumption through mechanisms such as night-time thermostat set-backs, and part of what’s being observed is how well those homeowners reduced their overall load. The DR assets of the RTP contract homes, as well as the DG units, are managed by their participation in an artificial real-time market that clears every five minutes. The market incorporates information from multiple sources, including the base transmission capacity and price (provided by a live Dow Jones feed of the wholesale price), virtual distribution feeder capacity and actual distribution cost, the current non-curtailable load, the current curtailable load and corresponding buy bids, and the current dispatchable DG capacity and corresponding sell bids submitted to the market on each cycle. From this information, the market determines a new clearing price for retail electricity every five minutes, and that clearing price is communicated to the DR and DG assets. Each of those assets then responds based on its most recent bid and the parameters defined by its owner. Implementing the System Using Event-Based Middleware The most innovative functionality in the Olympic Peninsula Project is the market- based control of DR assets in the RTP contract homes. The experiment requires each programmable thermostat to understand how to create a buy bid into the real-time market based on homeowner comfort goals, the current state of the device (e.g., the temperature in the home) and the current trends of the market. Note that the water heaters are not bidding into the market; they are using an open-loop control scheme in which they only respond to price signals from the market. Both the thermostats and water heaters then have to respond appropriately to the clearing price generated every five minutes before the cycle starts again. (The DG assets are also bidding and responding but using a different software and communication approach, so they are not discussed here.) The design and implementation of this part of the system is based on a prototype event-based programming framework called Internet-scale Control Systems (iCS) developed at IBM’s T.J. Watson Research Center. iCS is an example of what is currently emerging in the academic and research community under the category of cyber-physical systems, reflecting the increasing importance of monitoring and managing the physical world in a much richer and more detailed fashion. The physical world, in this case, is the electric grid and its associated enduse loads (such as heating and air-conditioning systems). In practical applications, there is an additional aspect that needs addressing. Cyber-physical systems will almost always operate within the context of some business environment. In the Olympic Peninsula Project, the business environment is reflected in the use of a market-based control scheme and the need for devices to be virtually augmented with business domain awareness – they need to bid into the market and react to clearing events. For this reason, IBM Research is focusing on an expanded scope of investigation referred to as cyber-physical business (CPB) systems, which includes both discrete, event-based systems and continuous data stream-based systems. The objective is to define a middleware framework that addresses solutions, such as intelligent utility networks, which involve the integration of the physical operations domain with the business domain, deals with the challenges of a highly distributed and heterogeneous environment, and also reflects the time-dependent nature of such integrated solutions. By using a loosely coupled event-programming approach with a very simple programming model, iCS enabled all the components of the system to be abstracted and represented as simple sensor, actuator or control objects in the market-control application – from the market itself all the way down to the heating element relays and load-monitoring sensors on the water heaters. The market-awareness and bidding/response algorithms were added in the middleware framework without modification of the devices themselves, essentially creating new, more intelligent virtual devices from the perspective of the market. This also allowed the design to be easily adapted in response to requirement adjustments or other issues that surfaced during development. In addition, iCS enabled the overall market-control application to be structured as a layered set of hierarchical control loops linked together through the event communication model. Another benefit of using a loosely coupled event-based approach is the level of resiliency it affords. The system was implemented so devices fall into a safe degraded mode if there is any loss of communication or failure in the market clearing signal. Operations continue in a less-than-optimal mode, but there is no catastrophic failure. Once the problem is resolved, the system returns to its optimal state. Early Results In spring 2007, the Olympic Peninsula Project is just completing the region’s winter electricity-constraint season. Several cold periods occurred, and the real-time market system operated as designed. It limited total load on the virtual distribution feeder to the configured capacity through price-based DR management, and it dispatched DG units when the market price for electricity met the sell bids. When no constraints existed, the market price was stable and in the expected range. In terms of performance, it appears there was more optimal shifting of load with the RTP contracts than with the TOU/CPP contracts. Another intermediate observation was that the fixed price contract homes sometimes shifted more load than the TOU/CPP homes. That may have been an artifact of the small sample size and the individual homeowners involved, but it is still an important result in that it indicates customers will take advantage of well-designed energy management tools, and may have further been motivated by having real-time information sources about their consumption and cost easily accessible. An additional positive indicator surfaced as a result of extending the project from its original end date of September 2006 to March 2007: Most of the residential participants agreed to continue their involvement, presumably because they were satisfied with the system’s positive impact on their electricity consumption and, to some extent, on their overall electricity cost. Conclusion The Olympic Peninsula Project has already succeeded in a number of dimensions, from demonstrating the effectiveness of a cyber-physical business system approach in designing such solutions, to generating a great deal of interest in and awareness of the optimal management of combined demand response and distributed generation in dealing with a variety of issues in electric grid operations. The goal of using this project as both an experiment and an educational tool is already starting to be realized. The project also represents an important milestone in the realization of the GridWise™ vision of an intelligent utility network – by integrating utility and customer assets; by leveraging advanced information technologies; and by bridging the operations and business domains of the utility environment. Further, it has been an extremely successful collaboration of industry and public organizations, including equipment and information technology vendors, investor-owned utilities, public utility districts, and the Department of Energy’s National Laboratory system. Filed under: White Papers Tagged under: Utilities About the Author Chris Trayhorn, Publisher of mThink Blue Book Chris Trayhorn is the Chairman of the Performance Marketing Industry Blue Ribbon Panel and the CEO of mThink.com, a leading online and content marketing agency. He has founded four successful marketing companies in London and San Francisco in the last 15 years, and is currently the founder and publisher of Revenue+Performance magazine, the magazine of the performance marketing industry since 2002.