An average refrigerator uses 36 kilowatt-hours (kWh) of energy in a month. In the event of a home electricity outage, most electric vehicle (EV) battery packs have sufficient stored energy to keep those pizzas frozen for weeks.

Indeed, with storms and fires interrupting home power supply more frequently of late, leveraging EV battery packs for resiliency have become an exciting solution to keep the electricity flow going. With the size of the global EV fleet rising from 8.5 million vehicles today, to 116 million vehicles in 2030, vehicle-to-grid (V2G) connections will only become more important.

What’s energy storage?

Electricity and broadcast TV are similar: Use it or lose it. Before streaming video, TiVo let us time-shift TV, so we didn’t have to miss “Desperate Housewives.” Energy storage allows us to time-shift electricity and has long been a tool for the electric grid. Traditionally, this has been in the form of pumped hydro, where water is pumped up a hill at night when energy is in less demand, and then run downhill to generate energy during the day.

Lithium-ion batteries began entering the energy storage market approximately 15 years ago, providing a unique ability of fast response. But the high cost and short charge duration limited these batteries to niche applications. Now, that is changing as the battery industry is transformed by the electrification of the massive automobile industry. Battery prices have already been falling from $1,000/kWh toward an expected $100/kWh in the next few years. Mobile EV batteries on the road already dwarf the current number of stationary batteries on the grid, and EVs are just getting started.

FASCINATING, BUT I NEED ENERGY IN MY BATTERY TO DRIVE THE CAR, NOT FOR THE GRID.

True, but using an EV as energy storage doesn’t mean it’s always discharging, just discharging at the right moments. Energy storage can provide a variety of applications for the grid, from frequency regulation to demand response. As an example, Californians recently experienced the need for energy storage when the grid hit peak demand in August. The California Independent System Operator (CAISO – aka transmission grid operator) had wholesale energy market prices top at $900 per megawatt (MW) during peak hours instead of the typical $20-40 per MW. More energy storage would have helped, and there was money to be made.

SOUNDS GREAT! SIGN ME UP.

There are still hurdles to overcome for V2G to be more widespread in North America. The hurdles fall under three categories:

Regulatory

First, accessing energy markets can be an obstacle. The CAISO market is not actually accessible where a car is parked. Charging stations are not connected directly to a wholesale market. There are good reasons for this, but new regulatory frameworks are opening up across the country to incorporate Distributed Energy Resources (DERs), such as solar, batteries and EVs. Wholesale market access is not necessarily a roadblock because there are other ways for V2G to provide value, including behind-the-meter operations, often called vehicle-to-building (V2B) or vehicle-to-home (V2H).

The second regulatory hurdle is with regard to interconnection or putting electricity onto a utility grid. In order to send energy back to the grid, a DER must have approval from the utility, or an interconnection permit. Solar pioneers had to blaze this trail of obtaining approval to interconnect. To keep utility linemen safe, the utility industry has regulations that require safety certifications for equipment. In California, those certifications have become incredibly complex with new requirements added every year, and many manufacturers are waiting to meet California requirements before launching across the United States. It is important to note that these certifications apply to V2G, V2B and V2H. Any equipment with an interconnection permit requires the certification, no matter the energy application.  

Technical

The discharge of an EV must be done through a charging station. Currently, only CHAdeMO (the DC charging standard used by the Japanese automakers) is capable of bidirectional charging. The CCS standard (DC charging adopted by the European and American automakers) is not yet capable of bidirectional charging, but it is expected to be capable in the next few years. Some companies have made custom modifications to enable bidirectional charging with CCS, and even J1772, but currently the Nissan LEAF and Mitsubishi Outlander PHEV are V2G capable off the dealer lot.

We should also address the 800-pound gorilla in the room. Tesla has been relatively quiet on V2G, yet very aggressive on battery energy storage systems. I do not anticipate any urgency from Tesla to implement V2G, as it would cannibalize their successful residential, commercial and utility scale energy storage business.

Cost

Bidirectional capability does cost more, and the economics need to make sense. Innovative business models can unlock this additional value of EVs, and higher volume can easily lower the cost of bidirectional vehicles. Utilities such as Con Edison in New York and San Diego Gas & Electric have launched V2G school bus pilots. Dominion Energy has funded a 500-bus pilot, with plans for an additional 1,000 V2G school buses over the next five years. School bus manufacturers Blue Bird, Thomas Built Bus, and Lion have all announced V2G capability on their products. Lucid Motors recently announced V2G capability, and many other original equipment manufacturers are engaged in active pilot projects.

I DON’T CARE ABOUT THE GRID; I JUST WANT BACKUP POWER FOR MY HOUSE.

This is coming to North America soon, with several CHAdeMO V2H products announced publicly. Wallbox, a Spanish company, debuted the Quasar, a 7kW V2H unit, at the Consumer Electronics Show this year. Ossiaco, a Canadian firm, has introduced dcbel, a V2H unit that also acts as a solar inverter. Additional systems designed for commercial fleets will be available soon, too.

I DIDN’T HAVE TIME TO READ THIS AND SCROLLED TO THE BOTTOM – WHAT’S THE POINT?

V2G is a solution for carbon emission reduction in two ways. First, the financial value of V2G can offset the higher cost of EVs, resulting in more clean cars, trucks and buses on the road. Second, EVs can provide cheap energy storage to accelerate the integration of renewable energy onto the grid.