It’s an interesting concept. We typically think of bringing an electric vehicle (EV) home to charge up and be ready for the next day on the road. This mindset can be turned on its head with the new generation of EVs offering batteries capable of bidirectional charging.
This allows the battery in the EV to be either charged from an alternating-current (AC) source of 110 or 220 volts, like is found in your home, or discharged to produce that same form of electricity. Now, what and where you use this power is only limited by your imagination.
Using solar at home to charge an EV battery is a very economic source. Once charged, the most straightforward use of EV power around the home is to plug tools, appliances or electronics directly into the bidirectional charger, instead of a home outlet when inexpensive solar electricity is not being produced.
Perhaps it can avoid the need for a long extension cord or generator if your EV can be located closer than your home to that which needs power. However, many are looking to use the EV battery to power the home directly, and this requires additional equipment and approvals.
Having a local supply of electricity at your home, whether it be from solar, generator or batteries, necessitates that these be isolated from the electrical grid in the event of an outage. This is to prevent harm to the workers attempting to restore the power.
An earlier blog on the Ford Lightning electric truck looks at its home backup capability in the event of a power outage, which can be extended further when combined with solar. Another use of EV battery power could be to offset expensive on-peak utility electricity and save on your power bill.
To this end, General Motors has announced a planned pilot program, EVs as Backup Power Sources, with California’s PG&E utility, using GM EVs. Of course, with both home backup and peak power shaving, it requires the EV to be at home with the battery charged.
The Nissan Leaf has had this bidirectional charging capability for over a decade and the car company offered LEAF at Home in Japan to allow it to assist in powering a home. The Mitsubishi Outlander PHEV became the first plug-in hybrid model with this capability. The Hyundai Ionic 5 and Kia EV6 are two recent EVs offering bidirectional charging.
Careful scanning of each manufacturer’s warranty fine print is necessary to understand what use is covered. If the EV is used daily for peak power shaving the battery would experience more charge and discharge cycles. Battery life is reduced through these cycles, so an intact warranty and performance guarantee is important.
Also, size does matter and each EV battery will have limitations as to the energy which can be withdrawn and how quickly. This battery capacity will determine if the entire home can be powered in the event of a blackout or only critical circuits. Similarly, can all on-peak consumption be offset, or only partially.
The economics and safety of using the EV battery for your home are enhanced by solar as a cleaner, less expensive source of charging that battery. Solar also provides sustainable charging capability even in the event of a catastrophic grid failure lasting weeks.
EV bidirectional charging and solar can share the investment in needed equipment, such as the inverter and lockout system, further improving the value and streamlining the applications.
Think of a future where a neighborhood or local community can have the added security of 10, 100’s or 1000’s EVs. These would have the ability to pool resources and draw on their collective battery power in a time of crisis to perhaps form microgrids or become portable power centers.
And that is where our collective imagination, ingenuity and technologies combine for us to save and keep safe!
