New California grid rules open door to V2G charging

California has approved changes to grid connection rules that will open the door for the interconnection of electric vehicles with two-way charging capabilities to the grid.

The changes to Rule 21 by the California Public Utilities Commission (CUPC) will pave the way for the faster deployment of distributed energy resources (DER) including solar and behind-the-meter batteries, but more importantly in the case of electric vehicles, to allow for bidirectional vehicle-to-grid charging.

When California was hit by a series of rolling blackouts across the grid in August, renewable energy critics and jumped on board, blaming solar and wind resources in much the same way the Australian media did in the case of South Australia’s 2018 blackouts.

Although neither, as Ketan Joshi points out on Renew Economy, were actually caused by renewables, transforming rules for the interconnection of distributed energy resources solar rooftop and electric vehicles can help introduce more flexibility in the grid to avoid blackouts in the first place.

As with Australia’s ANU V2G trial in collaboration with Nissan, V2G trials are being conducted in California such as this Nuvve Corp trial with local utility San Diego Gas & Electric (SDG&E).

However, until now, broad integration of V2G chargers has been held back by a lack of standardisation.

The changes made by the CPUC to Rule 21, which governs what kind of DERs may interconnect with California’s electricity grid, clears a way forward to standardise technical requirements.

The CPUC’s approved revisions of Rule 21 notes that the California energy commission established that “flexible electric vehicle charging could reduce the amount of renewable generation and energy storage selected to meet 2030 greenhouse gas planning targets”.

It defines three types of vehicle-to-grid integrations including V1G (one-way managed or “smart” charging), V2G AC and V2G DC (both referring to bidirectional charging systems).

While it does not consider V2G to be applicable to Rule 21, it notes that to date, interconnections of V2G systems have been done on a case-by-case basis.

The new rules allow bi-directional ev chargers to be interconnected to the grid as long as the operator gains utility permission.

California has a gigawatt hours worth of EV chargers, and as Greentech Media notes, “enabling them to export EV battery capacity, rather than simply stop charging, could make them an even more valuable grid resource.”

To be able to be used for V2G charging, EV charging equipment must comply with technical requirements before being approved for interconnection with the grid.

This includes ensuring that all V2G capable chargers to be used for DC interconnection comply with technical requirements to ensure uni-directional charging only as a default mode.

Only after gaining permission from the utility can EV chargers then be switched into bidirectional mode.