Plug-In Electric Vehicle (PEV) Submetering

Plug-In Electric (PEV) Submetering and Telematics

The California Public Utilities Commission (CPUC) continues to support innovation in electric vehicle (EV) charging through customer-centric policies that advance load flexibility, grid integration, and affordability. This includes implementation of the Plug-in Electric Vehicle (PEV) Submetering Protocol as adopted in Decision 22-08-024, guidance issued in Resolution E-5274, and ongoing exploration of telematics as a potential pathway to submetering. These efforts aim to give EV drivers access to time-varying rates and managed charging programs without requiring installation of a separate utility meter.

What is the Purpose of PEV Submetering?

Typically, customers can access PEV Time-Of-Use (TOU) electric rates by either installing separate electrical service and meter dedicated to PEV charging or enrolling their entire house or facility with a TOU rate. For the Submetering Pilot, separate PEV or "whole house" Time-Of-Use service is not required to access these rates. Instead, customers will use submeters available from third-party providers (known in the pilot as "Submeter Meter Data Management Agents") to measure their electricity use for utility billing purposes.

What are the Benefits?

PG&E, SCE, and SDG&E offer Time-Of-Use (TOU) rates for customers to charge their PEVs that may reduce their monthly travel expenditures. Submetering may provide additional value by avoiding the costs of charging infrastructure and other barriers to the adoption of TOU rates. In addition, encouraging night-time charging helps ensure that there is sufficient electrical grid capacity to meet the needs of all customers while minimizing cost and environmental impact.

CPUC Decision 22-08-024

In August 2022, the CPUC issued Decision (D.) 22-08-024, which adopted a statewide submetering protocol that allows electricity usage from EV charging to be measured separately from a customer’s main meter. The decision supports California’s clean transportation goals by enabling greater enrollment in EV time-of-use (TOU) rates and managed charging programs.

Key requirements under the decision include:

  • IOUs must implement submetering for all EV customers, excluding those currently enrolled in a net-energy metering (NEM) offering..
  • Utilities must begin immediately accepting submetering applications and perform billing reconciliation, even as system upgrades progress toward automation.

D.22-08-024 also acknowledged telematics as a potential future pathway for submetering and directed further exploration of its capabilities.

Resolution E-5274

In June 2023, the CPUC adopted Resolution E-5274, which approved the IOUs' submetering implementation plans with required modifications. This resolution provided further directions to accelerate progress and improve customer access.

Key provisions included:

  • IOUs must align monthly data transfer protocols with billing cycles and begin development of partially automated billing solutions.
  • PG&E and SCE were directed to remove customer enrollment caps in their submetering programs.
  • IOUs were instructed to clarify that Electric Vehicle Service Providers (EVSPs) and MDMAs may limit their participation in a utility’s submetering program to specific customer groups.

The resolution reinforced the Commission’s expectation that IOUs prioritize automation and standardization to support a scalable and accessible submetering framework.

Regulatory History

  • April 15, 2025: CPUC Energy Division hosted a public Submetering and Telematics Workshop to review IOU implementation progress under Decision 22-08-024 and Resolution E-5274, explore market perspectives, and gather stakeholder feedback on the emerging role of vehicle telematics in submetering.  Please see the link of video.
  • June 29, 2023: Resolution E-5274 approved the IOUs' submetering implementation plans with modifications and directed utilities to prioritize automated billing, update tariffs, and expand customer enrollment opportunities.
  • August 4, 2022: Decision 22-08-024 adopted the Plug-in Electric Vehicle Submetering Protocol and directed IOUs to file Advice Letters outlining plans for implementation, including MDMA onboarding, customer enrollment, and EVSE communication standards.
  • November 2016: Energy Division approved IOU advice letters with Tariffs and Agreements to implement Phase 2.
  • April 12, 2016: Energy Division hosted a workshop to review the results of Phase 1 and discuss Phase 2.
  • April 20, 2015: Energy Division approves IOUs' second revision to Submetering Tariff and Agreements.
  • August 7, 2014: Energy Division approves IOUs' revised Submetering Tariff and Agreements.
  • July 23, 2014: Energy Division holds meeting with IOUs and MDMAs to discuss the processes to be completed during pilot operations.
  • July 11, 2014: Submeter Meter Data Management Agents notice the CPUC of their participation in the pilot.
  • July 10, 2014: IOUs submit revised Submetering Tariff and Agreements in compliance with E-4651
  • June 26, 2014: CPUC Resolution E-4651 approves the utilities' request to implement a PEV Submetering Pilot.
  • November 13, 2013: CPUC Decision 13-11-002 modifies the utilities' requirements for the development of the Submetering Protocol.

Status Provided by IOUs in Submetering and Telematics workshop, April 2025

PG&E, SCE, and SDG&E are actively implementing submetering programs under D.22-08-024 and E-5274, with varying levels of progress:

Pacific Gas and Electric (PG&E)

  • PG&E is pursuing a three-phase billing modernization strategy: manual billing (initial), partial automation, and full automation (targeted for 2029). 
  • PG&E started approving MDMAs.  
  • PG&E emphasizes submetering as a key enabler of grid flexibility and EV innovation, citing pilot data that showed 46% of users shifted to off-peak charging and 91% reported satisfaction

Southern California Edison (SCE)

  • SCE launched its submetering program with a manual billing framework and is actively building internal training and outreach capacity.
  • SCE started approving MDMAs.
  • SCE is engaging with non-residential customers, EVSE vendors, and prospective MDMAs to grow program participation.

San Diego Gas & Electric (SDG&E)

  • SDG&E completed Phase 1 of its implementation plan by delivering a minimum viable product for automated submetering.
  • Phase 2, expected in 2025, will refine billing for more complex scenarios and increase scalability.
  • SDG&E has developed automated systems for Single Customer of Record (SCOR) enrollment; Multiple Customer of Record (MCOR) scenarios still require manual processes.
  • Although customer interest exists, no MDMAs have completed onboarding, limiting program participation.

Emerging Role of Telematics in Submetering

Telematics has emerged as a promising complement to traditional submetering approaches, enabling EVs to transmit charging data directly from the vehicle to utilities or third-party aggregators without additional hardware. This method can simplify participation, lower installation costs, and expand access to time-variant EV rates and managed charging programs. At the April 2025 Submetering and Telematics Workshop, stakeholders explored telematics’ potential and discussed:

  • Scalability & Accessibility: Telematics may offer a lower-cost, hardware-free solution compared to traditional submetering approaches that rely on EVSE or physical submeters, enabling access to time-varying EV rates and managed charging programs.
  • Integration Models: Telematic industry presentations outlined data-sharing pathways, including direct partnerships with OEMs that support utility communication.
  • Accuracy Considerations: While telematics supports load management today, stakeholders emphasized the need to validate its accuracy for use in billing. Variables such as auxiliary loads, energy losses, and sensor placement can affect data reliability.
  • Standardization Needs: Workshop participants highlighted the importance of developing common standards for telematics reporting, including data formats, accuracy thresholds, and cybersecurity protections.

As technology matures, telematics may expand the tools available for grid-interactive charging and enable new rate structures that better reflect driver behavior and system conditions.

Contact Information

For questions regarding submetering and telematics, contact Shiva Ourang of the CPUC Energy Division at shiva.ourang@cpuc.ca.gov.