Bidirectional Charging for EVs Finally Gains Traction

Back in 2007 when Ford built a batch of prototype Escape plug-in hybrids, a major component of the effort was to test vehicle-to-grid integration (VGI) with bidirectional charging. As the first modern battery EVs (BEVs) and plug-in hybrids were just emerging, there was a lot of excitement about the potential for VGI to help enhance the resilience of the electrical grid. Ultimately, a lack of both standards and critical mass of BEV adoption prevented VGI from gaining much traction yet. However, as BEVs are finally going mainstream, bidirectional charging may finally have its opportunity. 

By the end of 2022, the number of BEV nameplates available in the US market should double from 20 at the end of 2021 to about 40. Several already have bidirectional capability built in and many more will through an increasing number of pilot and commercial programs. However, instead of feeding power back into the grid, these newer efforts are focused on the edge with vehicle-to-home (V2H) capability. 

Leaf Was First

In 2010, the Nissan Leaf was the first affordable, modern BEV, and several years later, it was among the first to integrate V2H. Nissan uses the Japanese CHAdeMO connector for DC charging, which includes support for bidirectional charging. CHAdeMO-based V2H inverters have been available in Japan but have yet to be offered in the US where automakers other than Tesla use the Combined Charging System (CCS) charge connector. 

Unfortunately, as ubiquitous as CCS has become, bidirectional capability was a late addition with the ISO 15118 bidirectional communication standard still in development. Despite the standard not being finalized, an increasing number of automakers are deploying V2H capabilities in production. Lucid Motors launched its first product, the Air sedan, in fall 2021 with a bidirectional onboard charger and a compatible home charging unit scheduled to ship by mid-2022. 

Ford Goes Big

The Ford F-150 Lightning pickup truck comes standard with bidirectional capability over CCS. Ford has partnered with solar installer Sunrun to offer the Intelligent Backup Power V2H system using a smart inverter. The inverter has an integrated transfer switch that automatically begins drawing power from the truck when grid power goes out while disconnecting the home circuit from the grid. The system provides up to 9.6 kW and can power an average home for several days. When the grid comes back online, it switches back and recharges the truck. 

Volkswagen launched its new ID. Buzz electric minivan in early March 2022 with a similar system for V2H power backup. The ID. Buzz goes on sale in Europe in late summer 2022 and in North America in 2024. 

General Motors, which hopes to be selling 1 million BEVs annually by 2025, is also developing this capability. It has announced a partnership with Pacific Gas and Electric to pilot V2H capability with its new BEVs starting in the lab in summer 2022 and expanding to consumers by the end of the year. This program is also integrating demand response capabilities so that the utility can remotely switch the home over to pulling power from the vehicle during peak demand periods, reducing the load on the grid. 

Although none of these automakers have committed to standards compliance, the vehicles all have bidirectional charging hardware. The standard primarily governs communication protocols to manage energy flow. As all of these new BEVs are increasingly software defined, they will probably be able to comply with the final standard through an update. Full VGI is still probably many years off, but these developments are a good start.