As the energy transition accelerates, utilities are relying on advanced power grid software to navigate the complexities of integrating renewable energy, ensuring grid reliability, and meeting customer expectations. Distributed energy resource management systems (DERMS) have emerged as a pivotal tool, enabling utilities to balance diverse energy inputs in real-time while avoiding costly infrastructure upgrades.
Around 2020, ComEd, the investor-owned utility serving more than 4 million customers in and around Chicago, faced a growing challenge that had become increasingly common for electric utilities: A new wind project wanted to connect to ComEd’s western grid, a region already supporting several transmission-level wind farms. But this project aimed to tie into a 34 kV distribution line, which would have resulted in transformer overload with the added resource and threatened grid stability.
Under traditional firm interconnection rules, the project would have faced a binary outcome: either connect fully or be denied access. DERMS enabled ComEd to implement flexible interconnections, allowing the project to operate conditionally based on real-time grid conditions and avoiding costly infrastructure upgrades.
At the time, utility DERMS implementation was in its infancy. There was no clear playbook for deployment and the technology had already been cloaked in jargon and ambiguity by technology marketers. Even today, many utilities are struggling to demystify DERMS. Integration challenges have plagued others. But since 2021, ComEd has operated a utility-scale DERMS, one of the few of its kind in the U.S., supporting 8 GW of distributed energy resources (DER) capacity with minimal curtailments. How did they do it?
Taking the leap into DERMS
ComEd’s leap into DERMS began with a clear use case but would ultimately prove to be clairvoyant. In 2021, Illinois implemented a climate law that required 100% clean energy by 2050, and the software’s success could play a pivotal role in achieving that expectation.
The utility has interconnected more than 1 GW of DERs to its system, ranking Illinois first in the Midwest and second nationally in total capacity. Over the past five years, ComEd has supported 114% annual growth in DERs for residential customers and 25% annual growth for commercial and industrial customers.
The achievements highlight the critical role DERMS plays in helping ComEd optimize grid operations while meeting Illinois’ clean energy goals, according to Shikhar Pandey, who leads the ComEd team responsible for DER interconnection studies, non-wires alternatives, and valuing DERs. By facilitating real-time monitoring and flexible interconnections, DERMS allows ComEd to integrate more renewable energy resources without requiring costly grid upgrades.
“Flexibility,” Pandey said, can mean “you don’t have to build a new line, you don’t have to do anything” by leveraging technology and “utilizing the feature of your grid.”
GO DEEPER: Full interview with ComEd’s Shikhar Pandey
DERMS are not one-size-fits-all systems. They have evolved into several iterations, each tailored to address specific grid challenges:
1. Aggregator or Edge/Virtual Power Plant (VPP) DERMS: These systems manage behind-the-meter assets like residential solar panels, batteries, and smart appliances. Aggregator DERMS are customer-focused, facilitating engagement, enrollment, and performance tracking for DER participants while integrating with grid operations.
2. Grid DERMS: Designed for real-time visibility and control of grid-connected DERs, these systems integrate with Distribution SCADA or Advanced Distribution Management Systems (ADMS) to ensure operational stability. Grid DERMS often focuses on large, front-of-the-meter assets such as utility-scale solar farms or wind projects.
3. Enterprise DERMS: Acting as a “single pane of glass,” Enterprise DERMS bridges the gap between customer-facing programs and grid operations. They provide a unified platform for managing diverse DERs, demand response programs, and real-time grid needs.
4. Hybrid DERMS: Combining features from both Aggregator and Grid DERMS, Hybrid systems offer flexibility to manage assets across the grid and customer domains.
ComEd’s DERMS implementation aligns most closely with Grid DERMS, addressing operational issues like transformer overloading and voltage management. As Pandey explained, DERMS offers the ability to manage DER contributions dynamically in real-time, ensuring grid stability without requiring costly infrastructure upgrades.
ADMS vs. DERMS
While ComEd is deploying an ADMS to modernize grid operations, Pandey explained why DERMS had to be introduced as a complementary system rather than waiting for ADMS to handle all aspects of DER integration.
“We are trying to move towards [an] advanced distribution management system…taking the SCADA into the ADMS is the first step,” Pandey noted. However, the timeline and scale of ADMS implementation posed challenges in addressing immediate grid needs, especially as DER adoption accelerated.
DERMS was initially developed at ComEd to meet specific, urgent use cases that ADMS was not yet equipped to handle. One key driver was the need to manage high levels of DERs in real time, including flexibility to curtail DERs output dynamically based on grid conditions. This functionality is critical for addressing localized issues such as transformer overloads or voltage violations, which Pandey described as “nuanced use cases” that required immediate attention.
“There is no way we could have done it without DERMS,” Pandey said, explaining that ADMS was still in the process of being rolled out and integrated into ComEd’s systems. ADMS provides a platform to build on, he said, but while that system is being developed, DERMS is addressing specific customer needs and resolving challenges on the grid.
The ability to deploy DERMS independently from ADMS allowed ComEd to meet customer and regulatory expectations more rapidly. Pandey added that, in the long term, DERMS and ADMS are likely to be closely integrated, either through shared functionality or data exchange. Until then, DERMS provides the flexibility and real-time control required to manage the evolving grid.
Building DERMS capabilities from the ground up
ComEd’s Grid Integration and Technology (GrIT) Lab has been central to testing and refining DERMS capabilities. The lab enables engineers to experiment with digital twins and simulate real-world conditions for DERMS algorithms and controls. ComEd conducted extensive lab testing before going live to ensure reliable operation in the field.
Make no mistake: ComEd’s DERMS deployment hasn’t been without challenges— every new software tool comes with some headaches, and there’s a degree of “building the plane while we’re flying it,” Padney said.
A significant challenge in DERMS implementation, specifically, has been maintaining stable communication with DERs across ComEd’s grid. Communication is critical because DERMS relies on real-time data and control signals to dynamically manage grid conditions. Pandey highlighted the importance of seamless communication between DERMS and DERs, particularly in addressing operational challenges.
“If the customer side [doesn’t] have backup power in the event that something goes down, we lose communication,” Pandey said. Ensuring uninterrupted communication requires robust systems like private LTE and fiber networks, but smaller DER operators—such as independent solar providers or commercial businesses with rooftop solar—often lack the infrastructure to meet these needs.
Pandey explained that addressing these gaps has required ComEd to enforce new standards on backup power for communication systems. Without these measures, communication failures during critical moments could disrupt DERMS’ ability to manage grid stability. By working closely with DER owners, ComEd has established protocols that ensure reliable data flow, which is vital for curtailments, voltage management, and other dynamic grid functions.
Flexible interconnections and dynamic hosting capacity: The core of DERMS functionality
ComEd’s DERMS platform enables the utility to adjust DER generation dynamically, using a concept known as “dynamic hosting capacity.” Traditionally, a distribution feeder has a fixed capacity limit, meaning utilities must design the grid to the loading constraint to avoid overloading it during peak conditions. However, this approach often results in underutilized infrastructure, as the grid may operate well below its maximum capacity during off-peak times. With DERMS, ComEd is taking advantage of real-time grid monitoring and control to increase hosting capacity for distributed energy resources (DERs) without costly physical upgrades.
Dynamic hosting capacity allows the grid to accommodate more DERs by taking into account fluctuating grid conditions, such as load variations and real-time voltage levels. For example, during periods of low generation, DERMS can dynamically adjust to safely handle additional generation from solar or wind DERs. Conversely, during high-generation periods, the system can curtail DER output to prevent overloading transformers or feeders.
“This aspect of capturing the load dynamics and pairing it with generation is what we really call…dynamic hosting capacity,” Pandey explained. He noted that by pairing DER output with the real-time behavior of grid load, ComEd can maximize the use of existing infrastructure while still maintaining grid reliability.
Flexible interconnections are closely tied to dynamic hosting capacity and provide DER owners with conditional access to the grid based on real-time system constraints. Under traditional “firm interconnection” rules, DERs are either allowed full access to the grid or denied interconnection altogether if there is a risk of overloading infrastructure. This binary approach often forces utilities to invest in expensive infrastructure upgrades to accommodate new DERs. Flexible interconnections, supported by DERMS, allow DERs to connect without requiring permanent upgrades. Instead, DERMS uses real-time control signals to curtail DER output during constrained periods, such as peak demand or system faults.
ComEd’s flexible interconnection process has been particularly valuable for accommodating community solar projects and other DERs in areas with limited grid capacity. By avoiding traditional upgrade costs, this approach benefits both DER owners and ratepayers while enabling greater renewable energy adoption. While the flexible interconnection process currently relies on real-time measurements and manual oversight, future iterations could incorporate more automation to improve scalability. As Pandey noted, these systems must maintain robust communication between DERMS and DERs to operate effectively. Backup power, reliable communication networks, and real-time data integration will continue to play a critical role in scaling flexible interconnections and dynamic hosting capacity across ComEd’s territory.
DERMS: Looking ahead
ComEd is now working to expand its DERMS capabilities from pilot demonstrations to broader implementations. The utility is planning additional pilots in 2024, including a voltage management demonstration with a customer-owned microgrid. This project will test DERMS’ capability to manage voltage fluctuations by dynamically adjusting the smart inverter curve based on real-time data—a key feature for stabilizing areas with variable renewable generation.
Reflecting on ComEd’s journey, Pandey underscored the importance of stakeholder collaboration and regulatory coordination. ComEd continues to explore options for DERMS cost-sharing and developing guidelines for curtailment protocols as interest in DERMS grows.
Through DERMS, ComEd is showcasing how utilities can leverage advanced software solutions to meet the demands of the energy transition. DERMS remains a promising solution for utilities striving for grid resilience, cost-effectiveness, and sustainable growth in a rapidly evolving energy landscape.
