Standardizing Flexible Service Connection analysis in distribution planning
When a new or expanding customer requests service at a location where the distribution system lacks headroom, the traditional answer is to wait for an upgrade. A Flexible Service Connection (FSC) offers another path. The California Public Utilities Commission describes an FSC as an arrangement that lets a customer who is waiting for an upgrade use more power when expected grid conditions indicate it is safe to do so (California Public Utilities Commission [CPUC], 2026, p. 2). In practice, the customer receives firm but limited capacity under a defined load profile until the upgrade is complete.
FSCs are moving from one-off arrangements toward routine practice in some jurisdictions. In February 2026, the CPUC directed the state’s two largest investor-owned electric utilities to offer a standardized, tariffed FSC option to customers affected by distribution capacity constraints, acting on energization legislation passed in 2023 (CPUC, 2026). The same decision noted that parties to the proceeding were not aware of any standardized, scalable FSC process elsewhere in the United States that California could learn from (CPUC, 2026, p. 9).
A standard offer depends on something less visible: a consistent way for planners to decide how much capacity a constrained site can safely take, and when. This article describes how one large California investor-owned utility built that analytical foundation into its distribution planning process, and what the approach may offer other utilities considering FSC programs.
Starting point: a working program without a repeatable method
The utility had already shown that FSC could connect customers sooner in capacity-constrained locations, building on its Distributed Energy Resource Management System (DERMS). The next challenge was scale. Evaluating each constrained site involved manual data collection and analysis, and FSC work ran alongside standard distribution planning instead of inside it. As request volumes grew, that arrangement made results harder to compare from site to site and added to the analytical load on planners.
The project goal was to make FSC evaluation part of day-to-day distribution planning. Getting there required a common evaluation methodology and closer coordination between planning and engineering teams. It also meant automating the analysis steps that consumed the most planner time.
Building a standard evaluation methodology
The project team worked with planners and engineers to define a repeatable method for evaluating a constrained site and estimating the flexible capacity available to it. The output is a limited load profile: the share of requested capacity a customer may draw in each season and time window.
A simplified example shows the logic. A site requests 3 MW at a capacity-constrained location. Distribution planning limits the site to 10% of requested capacity (300 kW) from 9 a.m. to 9 p.m., March through October, and to 65% (1.95 MW) for the rest of the year. The customer can energize and operate within those limits while the upgrade proceeds instead of waiting years for full capacity.
Profile granularity is a design choice with trade-offs. The CPUC standard offer requires at least six values, two daily values for each of three seasons, and the decision observes that greater granularity can deliver more capacity to customers but takes more engineering effort (CPUC, 2026, pp. 24–26). A standard methodology gives planners a consistent basis for making that trade-off at each site.
Where a DERMS is in place, FSC can also support dynamic import limits that scale with grid conditions and generation availability. Static profiles are simpler to administer. Dynamic limits can release additional capacity during periods when the grid has headroom, at the cost of added communications and control requirements.
Flexible interconnection is one of several DERMS use cases covered previously on UAI; for background on how DERMS supports dynamic interconnection alongside virtual power plants, load management, and vehicle-to-grid integration, see Four DERMS Use Cases Supporting Smart Grid Operations for Utilities.
Integrating the method into planning workflows
With the methodology defined, the team embedded FSC evaluation in the utility’s existing distribution planning process. Constrained requests now move through the same review path, with FSC assessed as a standard option. Data collection and capacity analysis were automated, including integration with existing application programming interfaces (APIs), to reduce manual effort and variation between analysts. Planners received templates, documentation, and training so the method is applied the same way regardless of who runs it.
What the analysis showed across project sites
The standardized approach was applied to a large number ofconstrained sites, based on project analysis conducted with the utility. Several patterns emerged.
- Energy released was the primary value measure. The megawatt-hours FSC can deliver to customers before upgrades are complete give planners a common way to compare sites. Delivering more energy through existing infrastructure can contribute to downward pressure on rates, since fixed system costs are spread across more usage.
- A small set of sites drove most of the value. The largest contributions came from large sites and from sites that would otherwise have received no capacity (a 0 kW limit) until the upgrade was complete.
These measures align with what regulators may ask for. The CPUC now requires tracking of program costs and of additional energy consumption enabled for each standard offer customer at an hourly level, and it notes that the record to date was not sufficient to evaluate the cost-efficiency of existing offerings (CPUC, 2026, pp. 55–56). Utilities that build a consistent analytical record from the start may be better positioned to answer those questions.
Considerations for utilities evaluating FSC
The regulatory details will differ outside California, but several practical considerations carry over.
- Define the methodology before automating it. Automating an inconsistent process can scale the inconsistency along with the throughput.
- Treat FSC as a planning capability. Evaluating constrained sites inside the standard planning workflow can help keep results comparable across sites and planners.
- Plan the data record early. Hourly energy delivered, program costs, and curtailment incidents are among the data the CPUC now requires utilities to collect for standard offer customers (CPUC, 2026, pp. 35, 56).
- Align on ratings assumptions. The CPUC decision directs the use of normal equipment ratings without an added buffer, with profiles designed so equipment stays within emergency ratings if a customer using manual controls fails to limit load (CPUC, 2026, p. 45). Shared assumptions between planning and engineering affect how much capacity each profile can release.
- Plan for FSC as a bridge. Under the California standard offer, an FSC serves a single customer until the constraint is resolved and does not change the customer’s energization queue position (CPUC, 2026, pp. 18, 37). The decision reports an average duration of about three years for the existing load-limit arrangements it reviewed (CPUC, 2026, p. 10).
FSC changes the question planners ask about a constrained site. Instead of whether full capacity is available, the question becomes how much capacity is available, in which hours, and for how long. A standardized, automated way to answer that question is what allows an FSC program to grow with demand.
References
California Public Utilities Commission. (2026). Decision establishing a standard offer for flexible service connections (Decision 26-02-025, Rulemaking 24-01-018). https://docs.cpuc.ca.gov/PublishedDocs/Published/G000/M598/K715/598715449.PDF
About the Authors
Michael Emmanuel, Ph.D. has over 15 years of experience in utilities with a focus on power system operations, planning and DERs integration at both distribution and transmission systems domains. Dr. Emmanuel’s area of expertise includes DER hosting capacity analysis, DERMS, ADMS, market operations, and production cost modeling. In addition, he has led the development of regulatory aspects in a transformational platform to enable a true end-to-end monitor, control, and orchestration of DERs within both transmission and distribution systems.
Alec Kostovny is a Senior Consultant in Logic20/20’s Grid Operations practice. A highly skilled mechanical engineer with a background in designing and analyzing scientific-research satellites, he also has a strong knowledge base in clean energy. Alec brings in-depth experience on projects related to wind turbine design, solar cell development, hydrogen electrolyzer and battery design, and DERMS and microgrid implementation.
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