Two-Way Energy: Powering Homes With Electric Vehicles
Through bidirectional charging, electric vehicles can power homes and make renewable energy more efficient.
Electric vehicles (EVs) are no longer just a means of transportation. Increasingly, EVs are becoming integrated into homes thanks to bidirectional charging technology. This technology allows EVs to use electricity from the grid and feed it back, essentially creating mobile power storage units.
Volkswagen EV with bidirectional charging. Image used courtesy of Volkswagen
Advantages for Home and Grid
Bidirectional charging has potential benefits for homeowners. EVs can store solar power during the day and direct that power to the home at night when electricity rates are typically higher. It can provide backup power in case of a power outage. If the lights go out, the EV acts as a generator, keeping essential appliances running.
Bidirectional charging can also stabilize the electricity grid. When the grid experiences a surplus of renewable energy, EVs can soak up that excess energy and store it for later use. This can help prevent renewable energy sources from being wasted. When the grid needs an extra boost, EVs can return a preset amount of energy to the grid, reducing or even eliminating the need for the natural gas-powered generators used to meet peak demands today.
Automakers Offering Bidirectional Charging
Some automakers are now offering EVs with bidirectional charging capability. Volkswagen Vehicle to Home, for example, provides the ID.4 and ID.Buzz models with this feature. Volkswagen assumes the average consumption of a house is approximately 30 kilowatt-hours (kWh) per day, so a fully charged ID. model can supply electricity for around two full days. To ensure the EV can still operate, its high-voltage traction battery cannot be discharged below 20 percent state of charge (SOC).
Ford’s Intelligent Power Backup feature. Image used courtesy of Ford
Ford Intelligent Power Backup also offers bidirectional charging on its F-150 Lightning pickup truck. The Lightning can power a home for up to three days on a single charge if the home uses 30 kWh per day, and with power usage rationed, the battery can stretch for up to about ten days if only essential home systems are powered.
General Motors offers Ultium Home PowerShift bidirectional charging on its Silverado EV pickup truck. The Silverado can power a home up to 21 days on a single charge. According to GM, weather conditions, the life of the battery, the energy efficiency of appliances, and other factors may impact the duration. The GMC Hummer also offers Ultium two-way charging.
Vehicle-to-home charging can be paired with solar energy. Image used courtesy of Tesla
Tesla has been one of the pioneers in bidirectional charging, offering it on its vehicles since 2016. Tesla vehicles equipped with Tesla Powershare technology can power a home for over three days with a continuous 11.5 kilowatts (kW) during an outage. Tesla notes that no additional equipment is required when homes are equipped with Tesla’s Powerwall and Wall Connector.
What’s Next for Bidirectional Charging
Bidirectional charging is still in its early stages, but it can potentially transform how homes are powered. It could help save money on electricity, reduce our reliance on the grid, and provide backup power in case of outages. An increasing number of homes will be powered by EVs as the technology becomes more affordable and, subsequently, more widely available.
The U.S. government has strongly endorsed the idea, noting power backup to buildings to replace traditional diesel-powered generators, adding storage capacity to renewable photovoltaic solar power systems and similar distributed energy resources, and the addition of resilience to the power grid.
Moving forward, every EV may be equipped for bidirectional charging. When planning future EV infrastructure, it will be necessary to consider how fleets of charging EVs can provide emergency backup power for a more reliable power grid.