Flexible Service Connections as a Grid-Governance Instrument for Electric Truck Charging

Headline Finding

Flexible Service Connections (FSCs) — formal agreements allowing charging sites to connect to constrained distribution grids in exchange for curtailing load during peak hours — can cut energization timelines from years to months and unlock charging capacity that conservative utility planning would deny entirely. RMI’s analysis of ~2,000 PG&E feeders and ~900 National Grid feeders finds that with just four hours of load-shifting, 60% of PG&E feeders could support an additional 10 regional-haul heavy-duty trucks per day beyond conventional planning limits, rising to 80% for urban duty cycles. Scaled across all PG&E feeders, this could theoretically accommodate more than 25,000 regional-haul or 75,000 urban-haul trucks — exceeding the 57,000 zero-emissions medium- and heavy-duty vehicles sold to date in California — using existing infrastructure alone. The California Public Utilities Commission mandated standardised FSC offerings in February 2026, making this a live governance instrument with direct implications for the energy, fiscal, and spatial-allocation levers cities and regulators hold over fleet electrification.

Detail

RMI’s May 2026 brief analyses FSCs using publicly available feeder load data from PG&E (Grid Resource Integration Portal) and National Grid (New York System Data Portal), combined with truck charging load curves synthesised from Geotab telematics data. Approximately 2,000 PG&E feeders and 900 National Grid feeders were evaluated.

Core quantitative findings:

• With 4 hours of load-shifting, 60% of PG&E feeders can support an additional 10 regional-haul heavy-duty trucks per day; 80% for urban duty cycles.
• Half of all PG&E feeders can support an additional 10+ trucks with load-shifting required in just 1–2 months of the year.
• Scaled across all PG&E feeders: >25,000 regional-haul trucks or 75,000 urban-haul trucks could charge with no grid upgrades — more than the 57,000 zero-emissions medium- and heavy-duty vehicles sold to date in California.
• FSCs could absorb the >650 MW load growth expected from truck electrification in PG&E territory through 2035 (per RMI’s GridUp tool).
• Across all PG&E feeders in July, the median range between median load and max peak load per feeder is 1.7 MW, vs. less than 0.5 MW in National Grid territory. 90% of National Grid feeders have a peak-to-median-daily-load range of less than 1 MW, vs. just 30% of PG&E feeders.
• Increasing the flexibility limit from 1 MW to 3 MW produced only marginal gains, as the median peak prominence in PG&E is below 2 MW.
• Benefit increases substantially with flexibility window: the most common per-feeder benefit in PG&E rises from 1–10 extra trucks at a 2-hour window to 20–30 extra trucks at a 6-hour window; in National Grid territory the effect is negligible even at 6 hours.

Case studies:

• PepsiCo, Fresno, CA: obtained 1.5 MW of additional grid capacity 18 months earlier than conventional planning via PG&E’s FlexConnect program; gained access to 4.5 MW most of the time (vs. 3 MW at night only previously); enabled charging of an additional 20 electric semi-trucks; saved an estimated $1 million in f uel costs vs. diesel; avoided 8,000 tonnes of CO₂. PepsiCo added Tesla Megapack batteries to manage curtailment events.
• Terawatt, Rialto, CA: site has >6 MW nameplate DC fast-charger capacity; traditional process would have limited near-term power to just under 4 MW and required waiting multiple years for upgrades; via SCE’s LCMS pilot, Terawatt unlocked >80% of nameplate capacity for most of the year in exchange for lowering draw to <4 MW during summer evenings. Terawatt has since replicated this approach at additional sites.

Regulatory milestone: In February 2026, the California Public Utilities Commission adopted a policy mandating PG&E and SCE to offer standardised FSC programmes beyond pilots, establish tariffs, collect performance data, and guarantee that FSC participants do not lose their place in the load interconnection queue.

US electricity demand context: demand has grown at 1.7% per year over the past five years, vs. 0.1% per year over the prior decade.

Governance Implication

1. ENERGY LEVER — CREATED: FSCs are a distribution-grid governance instrument that converts a binary deny/approve connection decision into a flexible, conditional access regime. By allowing sites to connect at higher capacity for most of the year in exchange for curtailment during a handful of peak hours, regulators and utilities can unlock >650 MW of truck-electrification load growth in PG&E territory through 2035 without capital-intensive feeder upgrades — directly expanding the energy lever available to state regulators and utilities.
2. FISCAL LEVER — CREATED AND AT RISK: FSCs defer costly grid upgrades, reducing capital expenditure for utilities and connection costs for fleets (PepsiCo case: $1 million fuel-cost saving, 18-month acceleration). However, unresolved cost-allocation questions — who pays for eventual upgrades if investment is deferred, and who funds the controls and software required — represent a fiscal governance gap that regulators must close to prevent costs being socialised inequitably across ratepayers.
3. SPATIAL-ALLOCATION LEVER: RMI’s feeder analysis shows that FSC benefits are geographically concentrated near large population centres with residential load shapes (sharp late-afternoon summer peaks). Feeders on the urban periphery — where fleet depots cluster — are the highest-value targets. Utilities that proactively map and publish FSC-eligible feeder capacity can shape where fleet electrification infrastructure locates, making FSC programme design a de facto spatial-allocation instrument.
4. REGULATORY INSTRUMENT DESIGN: The CPUC’s February 2026 mandate establishes the key elements of a replicable instrument: standardised tariff, eligibility criteria, transparent curtailment terms, performance data collection, and queue-position protection. The contrast between PG&E’s dynamic day-ahead limits (operationally complex for fleets) and SCE’s static seasonal limits (easier to plan around) illustrates that instrument design choices directly affe ct fleet uptake — regulators in other states should start with static seasonal limits as RMI recommends.
5. GEOGRAPHIC TRANSFERABILITY LIMITS: The analysis of National Grid (Massachusetts and upstate New York) shows that FSC benefits are substantially lower where load shapes are flatter and winter heating loads constrain overnight charging windows — the primary flexibility window for fleets. Cities and regulators outside California should commission feeder-level analysis before assuming FSC programmes will deliver comparable results, and should target the most constrained feeders rather than applying programmes uniformly.

Sources

RMI, ‘Getting Electric Truck Chargers Online Faster: How flexible service connections cut delays and expand charging capacity,’ Gerard Westhoff, Nocona Sanders, Nick Pesta, May 19, 2026. https://rmi.org/getting-electric-truck-chargers-online-faster