Comed Drives Utility Affordability With Flexible Der Inte…

As energy demand continues to rise, electric utilities are focused on approaches and alternatives to costly infrastructure buildouts. Distributed energy resources (DERs) are consistently positioned as a means of meeting this demand, but interconnection challenges and logistics can prevent these solutions from achieving their potential at scale.  

Commonwealth Edison (ComEd) is working to redefine that paradigm, showing how utilities can collaborate with developers to fast-track flexible interconnections, lower project barriers, and protect customer affordability. ComEd’s blueprint enables new energy resources to connect faster by maximizing existing infrastructure over multi-year upgrades, proving that DERs can deliver value today while also providing a scalable model for the future.

Redefining Grid Capacity with DERs

Historically, utilities planned infrastructure around single-direction power delivery designed exclusively for peak customer demand, assuming worst-case scenarios maximum DER output during minimum load conditions. Under this traditional model, developers took on the full financial weight and timeline delays of physical grid upgrades. Flexible interconnections bypass those costly investments by leveraging underutilized grid capacity.

By allowing developers to connect under terms that include occasional, targeted curtailment during peak generation, utilities defer heavy capital expenditures, directly preserving affordability for rate-paying customers. Scott Wethy, senior manager of DER engineering and planning at ComEd, has been at the forefront of this shift, helping individuals and teams understand and embrace a new approach to old obstacles.

“Traditionally, utilities built the grid around peak demand,” said Wethy. “If a developer needed extra capacity, they paid for the physical upgrades. Flexible interconnections have really changed our capabilities and our mindset. By leveraging granular data, we can offer terms that let developers tap into existing grid capacity right away, agreeing to minor curtailment during peak conditions. As long as that curtailment keeps their business model viable, it’s a win-win for both the utility and the developer.”

Many developers initially feared utilities would drive them to excessive curtailment, while utilities worried developers would fail to curtail when called upon. To bridge this gap, ComEd analyzed three years of historical grid data to model precise curtailment expectations at specific interconnection points. By an estimated maximum annual curtailment threshold, ComEd provided developers and financing institutions the quantitative certainty needed to secure project funding.

To manage interconnection queues fairly as more resources join, ComEd established a pro-rata pool for projects within that d risk threshold, transitioning to a Last-In, First-Out (LIFO) queue for subsequent developers willing to accept higher operational risk for faster access. This evolution has also transformed daily control room operations in a way that makes sense for individual teams and wider departments.

“Under normal conditions, grid management should be fully automated so control room staff can focus elsewhere,” Wethy told Factor This. “Real-world operations mean handling the occasional out-of-compliance site. We’re bridging that gap by automating non-compliance workflows and consolidating alarms into a single interface. By training operators directly with our engineering team, we ensure they know exactly what the system is doing and how to handle exceptions when they arise.”

This shift showcases the power of moving from static to dynamic hosting capacity. Instead of capping connections based on conservative, worst-case assumptions, dynamic hosting capacity leverages real-time grid data to absorb significantly higher volumes of energy and also offers a scalable playbook for the broader industry.

Independent DERMS Compels Lessons Learned

While many utilities delay active DER management until completing an overarching Advanced Distribution Management System (ADMS) rollout, ComEd deployed a Distributed Energy Resource Management System (DERMS) as an independent, standalone control system. Driven by localized grid pressures in high-density areas their Mendota Network, where high wind and solar outputs threatened overloads during low-demand periods, ComEd chose immediate action over waiting for a multi-year master plan.

“We couldn’t wait around to build a system with every single bell and whistle,” Wethy said. “We had an urgent grid need to address today. The goal was to solve that immediate challenge right away, while structuring the platform so we could iterate and layer on advanced use cases over time.”

Deploying a DERMS first delivered rapid operational experience, proving that modular, targeted platforms can solve urgent grid bottlenecks without waiting on broader enterprise IT overhauls. When a storm or outage forces a feeder reconfiguration, ADMS communicates the updated topology to the DERMS. The DERMS instantly recalculates local non-firm constraints against the temporary network configuration, ensuring non-firm capacity limits are not accidentally breached on the re-routed circuit.

Extensive laboratory stress-testing proved vital before live field deployment, but navigating physical grid constraints is only part of the equation. Virtual Power Plant (VPP) initiatives can enforce fixed battery dispatches during peak hours, but if a VPP dispatches battery power onto a circuit already experiencing heavy solar output, it risks triggering an unintended DERMS curtailment event.

Breaking these bottlenecks requires aligning overlapping programs so real-time operational controls and market incentives work in tandem rather than in conflict. This integration challenge offers critical perspective for all participants.

“Engineers need to visualize both the problem and the solution, which is why technology providers need to lead with detailed, concrete use cases,” Wethy said. “Utility teams already understand their operational challenges, but they have to communicate those specifics clearly. What we all need to see is the exact piece of technology sitting in the middle that bridges the gap, and that means both sides need to get granular.”

Those specifics define a practical DER blueprint other utilities can replicate. However, the single biggest sticking point holding leadership back remains risk aversion and a reluctance to abandon traditional planning paradigms.

ComEd’s experience proves that grid capacity shouldn’t be thought of as a static, physical constraint, but as a dynamic resource that can positively impact customer affordability, which remains a top-of-mind issue. Their efforts outline a roadmap for utilities looking to move past traditional planning models and unlock the true value of DERs.