Recently a front-page story about Peyton Chapman, Lincoln High School’s principal, and her family enduring eight days without heat, electricity and Wi-Fi in a Portland home with six adults, four dogs, 13 sheep and 50 chickens appeared in The Oregonian. Quite an adventure.
The paper reported how Chapman retreated to a gas-powered car where she could charge her phones. She had recently contemplated switching to an electric car, she said, but is now glad she held off.
She is probably not alone in that thought. When the electricity is cut off aren’t you worse off with an electric car? Not necessarily. In fact you could be in a much better situation where you could power your home for several days using the electric car’s battery. The answer lies in an emerging feature in electric cars called bi-directional charging.
Bi-directional charging uses a particular type of EV charger that can not only charge your car but when the power goes off can reverse the direction of electricity from the car into your home. Ford’s F-150 Lightening truck is one of the first to offer this technology. The F-150 Lightning XLT trim has a 131-kW battery, the equivalent of about ten Tesla Powerwalls, which Ford says “can power your home for three days or even up to ten if usage is properly rationed.”
So how much power does your home use? That can vary substantially from home to home. One place to start is to look at some basic appliances. The largest Energy Star-certified refrigerators consume about 600 kWh per year or 1.64 kWh per day. That would suggest that the 131-kW battery in the F-150 Lightening could keep a sizeable refrigerator going for almost 80 days.
With that much capacity in an EV battery, how long could you keep a full home electrified? According to the Energy Information Administration (EIA), the average American home uses an average of 29,130 watt-hours per day. In theory the Ford F-150 Lightning could keep the average home running for 4.74 days. However in practice there are energy losses in this conversion, and you don’t want to completely drain your battery. So Ford’s estimate of three days is more prudent, and as Ford says if you cut back on using your appliances the F-150 could provide several more days of support.
Ford isn’t the only option. Nissan Leaf SV Plus, Tesla Cybertruck, Chevy Silverado EV RST, Chevy Blazer EV RS and Cadillac Lyriq all currently have Vehicle-to-Home bi-directional charging. Others such as Hyundai, Kia, Volkswagen and Tesla will incorporate this feature in their new models within the next couple of years. In each case you will need an electrician to install in your home a bi-directional charger with the proper interface panel to make this work seamlessly. The cost of this can vary between $3,000 and $9,000, about the cost of one Tesla Powerwall.
So what happens when the battery charge gets low? Because it is a car, you can unplug the EV from your home, drive to a high-speed DC charger and in less than an hour bring a fully charged EV back home to keep the power on. There are about 100 high-speed chargers in the Portland metro area. More than half of these are Tesla Superchargers with a documented “up” time of 99.95%. During the recent storm only two of these were without power. The good news is that you don’t have to own a Tesla to use them, as Tesla in the last year has opened up their Superchargers to virtually all other EV brands. The end result is that you now have the option to keep the power going on in your home almost indefinitely.
So how much backup could you expect an EV to provide for your home? PGE provides power consumption information on its website for each customer by the hour, day, month or year. Take a look at that information for your home to get an idea of what the base or lowest usage might be. Then do some internet research to decide where you might cut back. At that point check out what the bi-directional power specs are on the EV you are interested in and calculate how many days backup you will get before you need to go out to recharge your car.
Our recent storm is a wakeup call for all of us. Going without power for an extended time is not just unpleasant — it can be hazardous. Having a power backup plan is becoming more vital. Battery options can be expensive but not when you tap into the battery in your EV. Doing so can also be a safer option than fossil fuel backup systems such as a gas- or diesel-powered generator.
As a society we are in a time of transition as we wean ourselves off fossil fuel and move toward a future powered by renewable energy. As the influence of climate change accelerates and with it the probability of more extreme weather and potential power outages, we need to pursue power options that don’t make our climate worse. EVs with bi-directional charging to power our home can be a great option.
Duke Castle Feb 5, 2024 Updated Feb 8, 2024
