EPRI Helps PG&E Define Requirements for New Systems to Manage Distributed Energy Resources
EPRI developed reference requirements that enable utilities to define various features for DERMS, which are new types of software control systems that manage distributed energy resources. These requirements equipped PG&E to transition from a DERMS demonstration project to deployment of specific DERMS functions in its power system. “EPRI has been able to look across many utilities and see what the standard requirements could be,” said PG&E Grid Innovation Manager Alex Portilla. “Now that EPRI’s reference requirements are available, every utility doesn’t have to experiment on its own.”
Pacific Gas & Electric (PG&E) is no stranger to distributed energy resources (DER). The California utility connects about 5,000 private rooftop solar systems to its grid every month and has a total of more than 420,000 grid-connected solar customers.
These resources can result in two-way power flow on the grid, and PG&E faces the question of how to monitor, control, and harness their energy production while continuing to operate its power grid safely, efficiently, and reliably. The utility is considering the deployment of Distributed Energy Resources Management Systems, or DERMS, which are new types of software control systems that manage DER. During events on the grid, DERMS can address potential reliability and power quality problems by instructing DER to increase or reduce output. However, PG&E has found that identifying the right software systems is no easy task.
“This is a nascent area,” said PG&E Grid Innovation Manager Alex Portilla. “The technology is still rapidly evolving, and we as the buyers of the technology are still in the process of defining the functionalities and how they might fit into the overall operational technology portfolio. PG&E has been conducting demonstration projects to explore DERMS and related technologies to inform our future roadmap.”
“With more DER connected to the grid, utilities need new control systems to manage them,” said EPRI Technical Leader Ajit Renjit. “Many utilities do not have DERMS technology and have not defined the features and specifications they would want in such systems. This makes it difficult for commercial DERMS vendors to develop products that utilities can integrate seamlessly into their systems and processes.”
To take the guesswork out of the process, EPRI has developed a set of reference DERMS requirements. When planning, procuring, integrating, and operating DERMS, utilities can use these requirements to help define features such as architectures, functionality, scalability, reliability, speed and performance, points of connection with DER and other grid assets, user interfaces, integration with distribution management systems and advanced metering infrastructure, alarms, presentation of data and information, and security.
“EPRI has been able to look across many utilities and see what the standard requirements could be,” said Portilla. “Now that EPRI’s reference requirements are available, every utility doesn’t have to experiment on its own.”
“EPRI is taking a collaborative approach to develop these requirements,” said Renjit. “Utilities approach us with research questions that provide the basis for our technical studies. We also facilitate utility interest groups and vendor working groups and provide technical input on standards relevant to DERMS and DER integration. All these activities contribute to the development of requirements that can be supported by commercial products.”
After PG&E considered and applied aspects of the EPRI reference requirements, it was much better positioned to properly define the features for its Advanced Distribution Management System (ADMS). While grid operators use an ADMS for traditional distribution grid functions such as fault isolation and management, outage management, and automated voltage control, they use DERMS to predict and mitigate grid impacts of DER.
“We had initially viewed DERMS as the same system as the ADMS,” said Portilla. “But in EPRI’s framework, DERMS has one set of functions, and ADMS has a different set of functions. This helped us to define our needs more clearly. We were able to parse those out and specify the required interactions between the two systems. The immediate practical benefit was that we were able to develop a request-for-proposals that outlined the most appropriate ADMS functions for prospective vendors. We were also able to transition from a proof-of-concept DERMS demonstration project to deployment of specific DERMS functions at certain locations in our system.”
According to Portilla, the “biggest plus” of PG&E’s interaction with EPRI was the regular, in-person meetings with Renjit and his colleagues over a five-month period.
“What was helpful for me was the face-to-face interaction,” Portilla said. “A lot of the value came from talking through our plans, the questions EPRI asked, and the back and forth. It wasn’t, ‘EPRI, go write a report for us.’ It was collaboration every four to five weeks.”
According to Portilla, the move towards more standardization of cyber security-related DERMS requirements is particularly important because DERMS will communicate with third party-owned DER to enable key grid support functions.
“When utility systems are talking to hundreds of thousands of devices owned by external parties, you need standards to guide the actions and responses of all these devices,” said Portilla. “You can’t do commissioning tests with every single device. DERMS needs to be plug-and-play.”
According to Renjit, the challenge that PG&E faced with respect to clarifying functions and requirements in vendor solicitations is increasingly common in the electric utility industry.
“As utility customers deploy more DER, it is essential that utilities have the means to effectively manage the energy exported to the grid, which was originally designed for one-way power flow,” said Renjit. “This can result in greater use of clean energy such as distributed solar resources while supporting reliable, safe, and efficient operation of the electric grid.”
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Artwork by David Foster Graphics