All Teslas will support bi-directional charging by 2025. This was confirmed by senior VP of Powertrain and Energy Engineering Drew Baglino during Tesla's Investor Day event.
Bi-directional charging is the technology that allows an EV to send power back from its battery to other places - the home (Vehicle to Home or V2H), the grid (Vehicle to Grid or V2G), or to appliances, power tools and devices (Vehicle to Load or V2L).
The tech has been supported to some extent or another by automakers like Hyundai, Nissan, GM, and Ford (a big selling point for the F-150) — some praise bi-directional charging as the way of the future. In theory, it can reduce the home's dependence on the grid and take the stress away from the grid. It can also enable the battery packs in millions of potential EVs to work a decentralized power store while not in use.
Drew Baglino continued to say that Tesla is working to reduce the cost of power electronics in its EVs, and that the goal is to get more for less. “Most of the value comes in charging the car at the right time. It’s not really about sending the energy the other way [to the home].”
Tesla CEO Elon Musk said that not very many people will use bi-directional charging, because if they unplug the car, the house goes dark. He thinks the technology will work if there's a dedicated battery storage pack in the house, like Tesla's own Powerwall.