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Building the On-Ramp to Scale EV Flexible Service Connections
Building the On-Ramp to Scale EV Flexible Service Connections
Lessons from a Commercial EV Dynamic Flexible Service Connection Pilot Built Across Disparate Protocols and Technology Readiness Levels
Xcel Energy | The Mobility House
50-Minute Presentation
Overview
As utilities look to integrate commercial EV charging as a grid resource, two pathways tend to dominate the conversation: deploying advanced metering infrastructure (AMI) or procuring a DERMS platform. Both are foundational building blocks of grid modernization strategy, but neither is a prerequisite for getting started. Xcel Energy's Flexible Energization (FE) Demonstration at its EV and Grid Acceleration Test Facility located at SolarTAC exemplifies this by using existing communication pathways while laying the groundwork to work with both AMI and DERMS as their initial deployments progress. This results in a pilot that is a true on-ramp to scale, producing lessons around MVP architectures, controlling multiple assets behind a single DER endpoint, and what to keep in mind when translating protocols without common information models.
To accomplish this, Xcel Energy and The Mobility House (TMH) co-designed and deployed a commercial EV fleet charging site as a Flexible Service Connection using an on-site gateway, SunSpec Modbus RTU serial communication, and the OCPP 1.6J protocol already native to the charging hardware. The key to this configuration was reconciling not only disparate protocols, but also using them to facilitate aggregation and disaggregation within the site to meet Xcel’s needs for a reliable flexible service connection. This configuration can serve a pre-AMI, pre-DERMs utility, or flex to work with a utility that is transitioning to more sophisticated monitoring and control of its grid. The result is a demonstration anticipated to produce real operational data and shape how Xcel thinks about EV integration at scale, remaining relevant and useful even as the systems Xcel is using to monitor and control the site evolves.
Why This Communication Path and What It Took to Build
When Xcel Energy set out to develop solutions for commercial EV charging as a Flexible Service Connection, its DERMS selection and implementation was in the early stages of initial deployment. Rather than waiting to begin until everything was perfect, the team identified a practical on-ramp to begin addressing pressing grid constraints: an on-site gateway (WAGO) acting as a complement commercial relay, communicating to the utility using IEEE 2030.5 and southbound via SunSpec Modbus RTU. This approach offered two immediate advantages. First, IIEEE 2030.5 is already used for solar and storage DERs at utility substations, making integration familiar to operations teams. Second, Xcel could leverage TMH’s already existing ability to manage the chargers via OCPP 1.6J.
Making this work required solving a fundamental architectural mismatch. OCPP 1.6J, the protocol spoken by the EV chargers, operates at the individual charger level. SunSpec Modbus, by contrast, represents the need to represent a site level DER at the Point of Connection: a single entity as seen by the grid operator. Translating between the two meant designing explicit aggregation logic to allow multiple individual chargers, each reporting their own status and fault conditions independently, to become one coherent site state that is meaningful in the Flexible Service Connection context. Additionally, unlike IEEE 1547 ecosystems where common information models are increasingly available, OCPP 1.6J and SunSpec Modbus were developed for fundamentally different use cases and do not share a common semantic model. Translation was therefore required between generation-centric smart inverter controls and load-centric EV charging controls.
TMH developed this translation layer within ChargePilot, its Smart Charging Controller, producing SunSpec Model 701 (DER AC Measurement), 702 (DER Capacity), 703 (Enter Service), 704 (DER AC Controls), and 803 (DER Control) registers from real-time OCPP telemetry and on-site meter data. Specific decisions included how to compress OCPP error codes into the Model 701 Alrm bitfield (e.g., whether a single charger reporting a ground fault out of thirty should set the site-level GROUND_FAULT bit), and how to represent site operating state in a single enum register when individual chargers may simultaneously be charging, faulted, and available.
The SunSpec 700-series data model was chosen deliberately. Because the same model set describes solar inverters and battery storage systems, design decisions made for this EV pilot are directly applicable to multi-DER sites. Because SunSpec Modbus shares a common data profile with IEEE 2030.5 and DNP3, the translation work done here is also applicable to utilities wishing to use other smart inverter communication languages with OCPP 1.6J charging infrastructure.
Early Lessons: Technical and Programmatic
Phase 1 of the pilot is producing lessons across three dimensions:
Aggregation logic is a design choice, not a given. Neither OCPP nor SunSpec resolves how individual charger states map to site-level DER state. Every utility or integrator implementing this translation will face the same decisions. Documenting these choices explicitly, and understanding their implications for grid visibility, is one of the most transferable outputs of this pilot.
You do not need a DERMS to start learning. An on-site gateway with standardized Modbus communication can deliver real DER observability and control using infrastructure utilities already own. This approach is not a substitute for enterprise DERMS or AMI at scale, but it is a fully functional intermediate step that generates the operational experience needed to make those procurement decisions well.
Technology pathways can evolve as scale grows. Phase 1 uses a subset of SunSpec Modbus registers, deliberately kept minimal to reduce implementation risk. Phase 2 is scoped to migrate to full SunSpec certification, completing the Common Model preamble and shifting to standard register layouts, without rearchitecting the control logic. The pilot was designed from the start with this upgrade path in mind.
Customer adoption pathways become visible early. Running a live pilot before DERMS selection gives Xcel direct insight into commercial customer experience, enrollment friction, and operational workflows, all of which will directly inform how the utility designs its broader flexible energization program.
What Attendees Will Take Away
This session is designed for utility engineers, DER program managers, and technology integrators evaluating EV charging as a grid resource. Attendees will leave with:
- A replicable architecture for EV-as-DER pilots using on-site gateways and SunSpec Modbus, applicable regardless of whether a DERMS or AMI is in place
- A detailed walkthrough of the OCPP 1.6J to SunSpec 700-series translation decisions, including site-level state aggregation logic and alarm mapping
- Xcel Energy's firsthand perspective on what they learned, what surprised them, and how the pilot is already shaping their Grid Edge strategy
- A practical framework for utility DER pilots that are designed to scale, building on existing protocols today while preserving a clear upgrade path to certified, enterprise-grade integration
Presenters
Xcel Energy: Francisco Munoz Martin, Principal Electrical Engineer, Distribution Transportation
Francisco Munoz Martin is the principal engineer supporting Xcel Energy's flexible service connection and transportation electrification initiatives. He creates processes to enable transportation electrification for residential, commercial, and fleet applications, developing conceptual and forward-looking models of where and when fleet vehicle and public charging might be expected along with analyzing the grid impact and planning required to efficiently interconnect EV charging infrastructure to the Distribution system. He provides engineering support and coordination between fleet and commercial owners and Xcel Energy to assess capacity and balance charging requirements with existing electrical infrastructure. He also supports strategic company mid- and long-term resource plans and regulatory filings related to new load growth on the Distribution system caused by EV charging. Francisco is Xcel Energy’s point-of-contact for programs conducted by different research labs and organizations to develop the tools, technologies and regulatory environment required to enable the deployment and sustain EVs at scale, including the Electric Power Research Institute (EPRI) – EVs2scale2030 Program and the Alliance for Transportation Electrification (ATE) – Load Forecasting Group. Francisco has a Master of Science degree in Engineering, Electrical Specialty, from the Colorado School of Mines and a Bachelor of Science degree in Electrical Engineering from the University of Colorado Denver.
The Mobility House: Elizabeth Hughes, Product Systems Architect
As a forward-thinking product strategist and systems architect, Elizabeth Hughes advances next-generation energy and mobility innovation through deep technical insight and cross-sector collaboration. She combines electrical engineering rigor, product acumen, and stakeholder fluency to deliver technologies that are reliable, compliant, and ready for scale in the evolving clean energy ecosystem. Leveraging her background in electrical engineering, along with her work with utilities and standards organizations, Elizabeth builds scalable architectures that bridge electric vehicle infrastructure, distributed energy resources, and emerging interoperability standards to accelerate electrification and grid modernization. She is a proven contributor to UL 3141 and CSA 343, driving clarity and alignment across manufacturers, utilities, and regulators. She is recognized for translating complex engineering and policy frameworks into actionable product strategies. Prior to joining TMH, she held various roles at General Electric within their power grid division, working at the intersection of commercial strategy and technical execution. Elizabeth has a Bachelor of Science degree in Electrical Engineering from the Rochester Institute of Technology.
The Mobility House: Jacqueline Piero, US Head of Policy & Regulatory Affairs
Jacqueline works with stakeholders at the state and federal level on
standards, regulations, and legislation to establish frameworks for
standardized use of smart charging and load management by fleet owners
and utilities. Jacqueline has worked for more than a decade reframing
electric vehicles as Distributed Energy Resources in regulatory and market
spaces, primarily focusing on regulatory development around bi-directional
vehicle-to-grid resources. Last year she joined The Mobility House to help
streamline use of EV automated load management technologies in the
United States to mitigate the need for infrastructure upgrades as EV market
share increases.
