How your car can power your home

Even as fierce winter winds knocked out power to thousands of Bay Area homes, Tammy Snyder’s rural storm-battered house remained bathed in brightness.

Her plug-in hybrid Chevy Volt, linked to the house by long extension cords, powered her family’s favorite lamp, as well as the refrigerator, internet and furnace. It charged the batteries that run her phone, laptop, electric blanket, camp light, flashlights, power tools and a comfy heating pad that wraps around her shoulders.

“It’s turned outages into slight inconveniences, rather than the hardships they used to be,” said Snyder, a 62-year-old who radiates practicality. Her family’s scenic Santa Cruz Mountains home is more than a dozen miles away from the comfort of the nearest town — and lost PG&E power 13 times this winter, once for eight days and another for six days.

Her homespun setup is a preview of what may soon be easily available to many Californians: EVs that are equipped not just to receive power, but also to deliver it.

A new bill, proposed last month by State Sen. Nancy Skinner, D-Berkeley, would require that all new electric vehicles in California are equipped with so-called “bidirectional” charging by 2027. Passage of SB 233, which will be heard tomorrow before the Senate Energy Committee and on April 25 before the Senate Transportation Committee, could make two-way charging the norm, not a special feature.

“EVs are energy storage on wheels. Why waste that battery, given how few miles most people use the vehicle in any given day?” said Skinner, whose initiative was a major focus at this week’s California Climate Policy Summit in Sacramento. “But we need to make it as easy as possible.”

Electric car batteries can hold approximately 60 kilowatt hours of energy, enough to provide backup power to an average U.S. household for two to three days — or far longer, if the home’s electrical use is conserved.

Skinner’s effort comes as the Biden administration sets the stage for a major national expansion of EV use. On Wednesday, the EPA proposed strict new limits on emissions that would require as many as two-thirds of new vehicles sold in the U.S. to be electric by 2032. That’s a nearly tenfold increase over current electric vehicle sales.

California is already far ahead. Last year, 16.3% of new vehicle sales in the state were electric vehicles, far outpacing the nationwide rate of 5.8%. California is projected to have at least 8 million EVs on the road by 2030.

Meanwhile, state residents face a growing threat of rolling blackouts as the power grid is overtaxed during periods of peak demand, such as during the heat wave on Sept. 6, 2022, that brought outages to Alameda and Palo Alto. This winter’s parade of atmospheric rivers also caused widespread power losses.

By harnessing the untapped battery storage capacity of electric vehicles, California can address three challenges at once: cleaning up the air while keeping the lights on and reducing energy bills, according to Ellie Cohen, CEO of The Climate Center, based in Santa Rosa.

As the state moves into an all-electric future, “bidirectional vehicles can play a huge role to get to where we need to go, faster,” she said.

California’s cars will have 60,000 megawatts of stored energy in batteries by 2030, according to Siva Gunda of the California Energy Commission. If only 10% of that could be returned to the grid, “we can get through what we went through last year without turning on the backup generators,” said Gunda.

Now most EVs have one-direction charging. Power is taken from the grid and charges the car’s battery.

Only the Nissan Leaf, Kia EV-6, Hyundai Ioniq 5 and Ford F-150 Lightning offer built-in “bidirectionality” to homes or the grid. Tesla recently announced that its vehicles will be “bidirectional” by 2025.

PG&E strongly supports the move toward bidirectional vehicles, saying it is preparing the grid. “It represents a new path. We want to lead the country in reliability, resiliency and reduced emissions,” said Aaron August, vice president of PG&E’s Utility Partnerships and Innovation

But the state is not yet ready for immediate widespread adoption, said PG&E and other experts.

Procedural and regulatory changes are required before EV backup power becomes an everyday thing, said Jackie Piero of the Belmont-based company The Mobility House, which provides the technology that lets electric AC Transit buses power the Oakland Public Library during emergencies. “Smart meters” or other tools would be needed during outages to ensure that utility workers aren’t injured by a car’s energy, she said.

Standards, now in development, would help the grid protect itself, said PG&E’s August. Standards are also being designed to align how chargers talk to the car. For instance, Nissan and Ford currently use different strategies, requiring consumers to purchase different equipment.

Until then, resourceful “hackers” like Snyder have built their own bidirectional systems. A stay-at-home mom with a background in math and computer science, she loves nature, dancing, 5,000-piece jigsaw puzzles — and self-sufficiency. A neatly organized cart in her home holds eight 40-volt batteries, six 18-volt batteries, two 40-volt inverters and two 18-volt inverters.

The centerpiece of her EV setup is a 1500-watt inverter, which converts the car battery’s DC power to the AC power needed by her home. Bright blue, the inverter cost $220 and lives in the trunk of her car, a 2017 model.

The inverter hooks up, via cables, to the car’s 12-volt battery, which is propelled by the car’s big battery. It also connects to two long extension cords, 15 amps each, which are routed down the driveway to her home. One cord runs through a kitchen window to a power strip, supporting appliances and recharging batteries. The other cord runs into a closet, supporting the furnace and internet router.

“They’re just consumer electronics,” she said. “It only takes about five minutes. It’s easy.”

She doesn’t want the car to think it’s not really going anyplace. So she fools it. To keep it from automatically turning off, she enlists what she calls “the rubber band trick,” using three blue rubber bands around the gearshift button to hold it in place.

Snyder’s effort reveals the commitment of Californians to create greater reliability in an all-electric world, said Kurt Johnson of the Climate Center.

But simplicity is essential, he said, for many more residents to reap the potential of this approach.

“I want to live in a world where, if the grid needs power when I get home, I just plug in my car,” he said.