EPRI Smart Grid Demonstrations: An Update
- Written by Matt Wakefield
An assessment done four years into a seven-year program confirms the general effectiveness of demand-response, but identifies challenges with the business case for some technologies such as in-home displays. Conservation Voltage Reduction is proving to be an unanticipated cost-effective beneficial resource, while energy storage is found to be technically effective but still at the outer boundary of cost-effectiveness. With over two more years to go, the EPRI demonstration program will also assess virtual power plants and encourage more rapid smart grid standardization.
Results and lessons learned from smart grid investments are beginning to yield insights as to how emerging technology can optimize electric grid performance, how consumers respond to prices and new technology and which research challenges still need to be addressed. As detailed in a recent report, EPRI's Smart Grid Demonstrations 4-Year Update, Case Study Brief, we are beginning to see a steady stream of research results. The update includes results from thirteen case studies involving ten electric utilities and references over a hundred deliverables.
The EPRI Smart Grid Demonstration Initiative is a seven-year international collaborative research initiative demonstrating the integration of distributed energy resources in large-scale demonstration projects. The initiative, which began in 2008, leverages multi-million dollar smart grid investments in the electric utility industry and is prompting systematic study of which smart grid applications are most beneficial. The common goal is to share learning that covers a wide breadth of technology deployment and program results among 23 participating utilities, based on 15 demonstrations in 5 countries.
The four-year update report includes case study overviews depicting a full range of activities relating to the integration of distributed energy resources, including energy storage, renewables generation, demand response and consumer behavior. For example, three of the case studies – those from ESB Networks in Ireland, ComEd in Chicago and Kansas City Power & Light – share results related to consumer behavior.
Many consumer behavior studies are underway, some resulting in part from the U.S. Department of Energy smart grid grants. In some cases, these findings confirm the results of prior pilot programs, but others provide new and important insights into how consumers and businesses use and value electricity. ComEd conducted a demand-response pilot that was large in terms of both scale and scope, which employed an opt-out recruitment strategy to see if that resulted in greater participation and response. It found that only 5-10 percent of enrollees responded to high prices or other inducements to reduce load. However, those customers reduced usage 10-20 percent on event days, which is in line with what opt-in programs report.
Comparing such programs is challenging because of differences in the kinds of demand response programs employed, the types of customers recruited and variations in how pilots were designed and evaluated. An important research goal is to either reduce the variance of the performance metrics, or develop more precise ways to explain them. EPRI is assisting in the design of utility demand-response pilots with rigorous protocols employed to ensure that behavior-induced effects can be distinguished from other influences during analysis.
The pilots include tests of the program's effectiveness, the impact on electricity usage, response to home energy reports and response to devices that provide customers with information and feedback such as in-home displays. There are challenges associated these tests, including low acceptance of technologies like in-home displays: in one study, less than 30 percent of customers asked for them when they were provided for free, and considerably fewer when they had to be purchased.
Another challenge is to improve reliability of such devices so they are easily commissioned and work continuously in all types of home and building environments. These challenges also affect the business case. Customers that adopt the technology do reduce energy consumption a few additional percentage points below what they otherwise would have. However, the annual benefit to society from this behavior is estimated at only $10-20 per year, while the cost of each display could exceed $100. These devices need to be made more effective, or we look for lower-cost ways to give consumers feedback. Though there is still a lot of optimism about consumer response mechanisms in the smart grid world, practically speaking, there is a lot of work to do if expectations are to be met.
On the other hand, an area of benefit that was not highly anticipated when this project started in 2008 is Conservation Voltage Reduction, which can reduce distribution losses and lead to consumer savings. This approach has been used for decades, but what is changing with the smart grid is the utilities' ability to better optimize performance with data coming in from new communications infrastructures, lower-cost voltage sensors being deployed along distribution feeders, smart meters and flexible operational strategies.
Preliminary results from a conservation voltage reduction field trial that was part of the EPRI Distribution Green Circuits project suggest that energy savings of 1.2 to 2.4 percent can be achieved. Since performance varies depending on the unique characteristics and loads of each feeder, careful analysis is needed to anticipate performance as technology deployment decisions are made.
In Sacramento Municipal Utility District's (SMUD's) demonstration, initial tests reported peak demand reduced by an average of 1.7 percent. Additional testing is needed among a larger pool of substations to determine the predictability of this performance, but these promising results are consistent with similar projects. Some of the challenges associated with this technology deployment have to do with how to perform measurements and verification economically and reliability.
Gaps identified in the EPRI initiative are resulting in new collaborative R&D projects to perform targeted research. A dimension of energy storage is one example. The technical impacts of energy storage are proving to be beneficial, as shown in modeling done American Electric Power's (AEP's) demonstration, but the economic value of those benefits does not as yet outweigh the costs. EPRI's Battery Storage Systems and Application Demonstration is helping to fill that gap with additional research.
A second instance is how to obtain value from the data generated from smart grid technologies. Southern Company's case study uses Advanced Metering Infrastructure (AMI) to monitor the health of capacitor banks to cut the capacitor bank inspection schedule from annually to daily. Innovative approaches to turn existing systems and data into value may provide significant benefits to the electric utility industry. EPRI's Distribution Modernization Demonstration on Big Data is a new five-year demonstration project that addresses that need.
In the final two and half years of this seven-year smart grid demonstration program, we will continue to focus on the "integration" aspects of distributed energy resources and associated benefits assessment. The vision has been to understand how a "virtual power plant" may aggregate distributed resources and be treated on the same plane as conventional generation by system operators to optimize utilization of these beneficial resources. Although we are making progress in this front, there is still a lot of work to be done in the industry. Standards development and uptake have been slower than anticipated, but efforts such as those by the NIST Smart Grid Interoperability Panel are making a difference to accelerate adoption of standards. By collaboratively applying standards-based integration techniques and performing case studies in demonstrations, successes can be readily shared within the utility industry, while key gaps can be identified to prioritize future research.