A submetering protocol was introduced by the California PUC to accelerate the growth of electric vehicles (EVs).
The protocol, along with the communication protocols for electric vehicle charging equipment, aims to allow users of plug-in electric vehicles to take advantage of special off-peak electric vehicle charging rates without the need to install a separate utility meter. and should therefore reduce the cost of charging.
With the sub-meter, which will be customer-owned – with the market indicating a trend towards integrating sub-meters into charging stations – users can have their EV charging metered and billed separately from their main meter.
The decision, which has been under consideration for about a decade with several pilot assessments, applies to the big three IOUs Pacific Gas and Electric, Southern California Edison and San Diego Gas & Electric as well as Liberty Utilities CalPeco Electric, Bear Valley Electric Service and Pacific Power.
The protocol is also considered the first for a US state.
“The sub-measure makes electric vehicle charging cheaper and will help boost [their] growth across the state,” said Commissioner Clifford Rechtschaffen, who is in charge of the process.
“It’s a practical solution to one of the significant barriers to the widespread adoption of electric vehicles.”
A statement from the CPUC indicates that special EV rate structures for less expensive power during off-peak hours are often inappropriate for the entire home or commercial facility where EVs are located.
Additionally, few customers are willing to invest in a separate utility-grade meter.
Sub-metering should also enable EV charging to participate in V2G demand response programs by decreasing EV charging load or feeding power back into the grid.
The ruling sets a 1% accuracy requirement for submeters and also specifies connector and communication requirements for charging equipment, which are consistent with recently approved California utility EV programs.
California is considered a leader in electric vehicles with more than one million units sold in the state, representing nearly half of national sales, and they account for more than 16% of current passenger vehicle sales.
The CPUC reports that it has authorized utilities to spend more than $1.5 billion on EV charging and has asked them to create a menu of special EV charging rates.