Powering Strong Communities

California Regulators Vote To Allow Submetering Of Electric Vehicles

The California Public Utilities Commission (CPUC) on Aug. 4 made California the first state in the nation to allow electric vehicle (EV) owners to measure an EV’s energy use independently from the owner’s main utility meter through submetering.

Separately metering EV charging independently from a customer’s main utility meter is crucial because special rate structures apply to EVs that allow customers to buy less costly power during off-peak times, the CPUC said.

Those rate structures are often inappropriate for the entire home or commercial facility where the EVs are located, it noted.

The decision applies to the following utilities: Pacific Gas and Electric, Southern California Edison, San Diego Gas & Electric, Liberty Utilities, Bear Valley Electric Service Inc. and PacifiCorp.

“The inability to submeter has been a major barrier to the expansion of EVs because taking advantage of EV-specific rates significantly lowers the total cost of ownership of an EV but few customers are willing to invest in a separate utility-grade meter,” the CPUC said.  Submetering will also allow EV charging to participate in demand response programs by decreasing the EV charging load or even feeding power back into the grid when it is needed most.

The decision also adopts communication protocols for EV chargers, which are often called EV Service Equipment (EVSE). The communication protocols are consistent with recent CPUC-approved utility EV programs, as well as with the California Energy Commission’s (CEC) recommendations for EVSE.

The CEC has deemed these standards as vitally important to ensure interoperability with publicly funded EV charging infrastructure and to ensure the state achieves convenient, grid integrated charging.

The CPUC said that both aspects of the decision are crucial to enable widespread Vehicle-Grid Integration (VGI) and to capture the resulting grid benefits.

VGI refers to a suite of actions that shape vehicle charging behavior -- such as changing the time or level of charging, or how power is sent back to the electric grid from vehicles -- in ways that maximize both consumer and grid benefits.

“As the number of EVs in the state grows rapidly to meet our state’s climate goals, VGI will ensure that the electric grid is not stressed by the new load and will also allow customers to buy electricity at the cheapest times,” the CPUC said.

The proposal voted on is available at: docs.cpuc.ca.gov/PublishedDocs/Published/G000/M496/K405/496405751.PDF.