The next frontier for an energy transition pioneer: bidirectional EV charging

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Seven years ago, I wrote a story about my friend Justin Guay’s sometimes exasperating journey to retrofit his home in the San Francisco Bay Area in a quest to get off fossil fuels.

Published at the much-loved, sadly now defunct, site Greentech Media, the story struck a chord with readers. For several months, it was one of the most-read stories at the site.

Readers were clearly hungry for practical information on how they could wean their homes from fossil fuels as Justin had. His experience, then novel, is becoming mainstream. Boosted by incentives in the Inflation Reduction Act, critical technologies for an all-electric home like heat pumps are beginning to outsell their gas-fired competitors.

Fast forward to today, Justin and his family have resettled in Midway, Utah, located in the shadow of the Wasatch Mountains about 30 miles southeast of Salt Lake City. This time, Justin built an all-electric home from the start and powers it with a 15-kilowatt rooftop solar photovoltaic system.

A professional climate advocate, formerly with The Sunset Project and now a program director at the Quadrature Climate Foundation, Justin is once again at the energy transition’s leading edge.

Top of mind for him now is not just reducing his carbon footprint but being able to live in and adjust to a world remade by climate change.

“If the first wave of home electrification was about dealing with the underlying climate problem, the second wave is about managing the new climate reality,” he told me in a recent interview.

In pursuit of that goal, he just bolstered his home’s energy resilience by tapping the giant battery in the truck parked in his garage.

Getting more use from the battery you already have

What Justin realized is that the battery in just about any electric vehicle sold today is at least several times larger than any single residential battery. And in his case, it is much bigger.

Tesla’s Powerwall 3 home battery has a capacity of 13.5 kilowatt-hours (kWh), while Justin’s 2025 all-electric Chevy Silverado truck is equipped with a 205-kWh battery pack – 15 times larger.

Until recently, nearly all EV charging has been one way, with the charger feeding electrons to the battery. But when coupled with enabling technologies, many EVs can both receive power and send it back in the other direction.

Some EVs – notably, the Nissan Leaf – have had bidirectional charging capability from the beginning. What’s changed is that more automakers are either making EVs capable of bidirectional charging or manufacturing the equipment that makes bidirectional vehicle-to-home (V2H) charging possible.

GM has done both. Justin’s Silverado EV truck was able to provide back-up power to his home after he installed GM Energy’s V2H Bundle, which includes both a Level 2 EV charger and V2H enablement kit.

For now, Justin’s Silverado battery kicks in only in emergencies, when the grid goes down. GM doesn’t allow for other uses of its vehicle batteries such as time-of-use arbitrage – i.e., selling power to the local utility when power is scarce and prices spike – because of warranty and battery degradation concerns.

“Not that that would make any sense where I live because our electricity prices are so cheap,” Justin tells me. “The delta is four cents – seven cents off-peak, 11 cents on-peak – don’t tell anyone in California!”

“Wild West light”

Getting the V2H Bundle installed and turned on was not easy.

If fully electrifying his previous home was “the Wild West,” the new project felt like “the Wild West light,” he says.

“This is the first generation of these technologies that’s coming out. It was really hard to find somebody who had any familiarity with the system. I got really lucky and found an electrician who was up for figuring it out.”

After a software glitch and the replacement of a failed dark start battery, the electrician was able to activate the system on the third try.

As an early adopter, Justin was willing to put up with these “teething issues.” GM “doesn’t have people they can send out to your house if it doesn’t work. Luckily, our electrician was awesome, and he spent hours on the phone with the GM Energy guy,” he says.

On the third try, the electrician turned off power to the house, the house connected with Justin’s Silverado EV, and the lights came back on.

“I have to admit, that was one of the best moments in this whole energy independence, get-off-fossil fuels journey,” he says.

The new climate reality

Justin acknowledges not everyone has the money and patience to see a project like this through.

“It’s still a splurge, let’s be honest,” he says. “It’s not the amount an average, normal person will be able to lay out. We’re the first adopters, so part of what we’re doing is hopefully bringing down the cost curve.”

Justin paid $4,000 for the V2H Bundle on sale at the end of 2024 (it now lists for $7,299, or $6,799 before March 31) and another $3,000 for the electrician to install it.

But Justin says the investment is worth it for peace of mind.

Public Safety Power Shutoffs for wildfires are of increasing concern where he lives in rural Utah. His home insurance was even canceled recently. “They didn’t tell me why. I assume it’s because of wildfire risk and the changing climate,” he says.

“Part of what drove me to want to get the system was I’m not so worried about the normal, routine power outages, but you just never know with fire danger,” he adds. “Now, I can power my fridge, keep my food from going rotten, keep my Wi-Fi on, keep on my TV, lights, and heat pump water heater” – all for several days, with the power stored in the Silverado’s battery.

“It’s not perfect,” he says. “It won’t run my heat pump. The inverter is a bottleneck. It’s the equivalent of diesel gen set.”

But he notes, “if you have a gas furnace, it’s going to kick off in an outage because it needs electricity, too.”

Justin is confident V2H systems like his will catch on. He may be right.

The Massachusetts Clean Energy Center announced in early March it will deploy 100 bidirectional EV chargers at no cost to residential, commercial, and government customers as part of a two-year demonstration program. And Kia recently announced pre-orders for the Wallbox Quasar 2 home charger that will enable bidirectional charging for the automaker’s EV9 all-electric SUV.

Justin believes bidirectional EV charging could even make conventional stationary residential energy storage systems like Tesla’s Powerwall redundant.

“I don’t think there’s any business case for a Powerwall once this becomes more mainstream,” he says. “You’re going to buy a truck or a car anyway. You’re making multiple uses of the same asset.”

“As long as we allow these technologies to continue to develop, and bring down costs, it’s going to be incredible what we’re able to do with it.”