Tesla vehicles will be capable of bidirectional charging within the next two years, according to comments from Tesla VP Drew Baglino at today’s Investor Day event.

A question was asked during the Q&A portion about whether Tesla would move towards enabling bidirectional charging on its cars, noting the company’s historical reluctance to do so.

Drew Baglino, Senior VP of Powertrain and Energy Engineering, answered the question by noting that the lack of bidirectional charging was not really a conscious decision, but rather not a priority at the time. But, as Tesla has improved its power electronics units, it has found ways to reduce cost while also bringing bidirectional charging to its vehicles.

Baglino went on to say that this could happen within the next two years, as Tesla is currently within a retooling process for their power electronics manufacturing.

But immediately after this answer, CEO Elon Musk stepped in to pour a little cold water on the idea, stating that “I don’t think very many people are going to want to use bidirectional charging, unless you have a Powerwall, because if you unplug your car your house goes dark, and this is extremely inconvenient.”

The answer was interesting because it gives a little insight into what Tesla’s thinking has been about bidirectional charging all along.

Bidirectional charging is the capability of a car to not only take power to charge the battery, but to send that power back to power devices, a home, or even the grid. These are further categorized as Vehicle-to-load, vehicle-to-home, and vehicle-to-grid, or V2L, V2H and V2G respectively, and sometimes categorized overall as V2X.

Historically, Tesla has indeed opposed putting bidirectional charging systems on its vehicles. Most manufacturers have as well – only a few cars have bidirectional charging, and it’s often limited.

The Hyundai/Kia E-GMP platform cars are capable of V2L, Rivian is capable of V2L with potential V2H capabilities coming later, and Ford’s F-150 Lighting is capable of V2L, or V2H with its Ford Charge Station Pro. The Nissan Leaf is the only car we’re aware of with V2G capability, which has been built into the cars since 2013 but only recently got a charger that enables it, though Lucid has said they’re working on V2X for their vehicles as well.

So where does that leave us with Tesla? It sounds like they will have the technical capability of providing bidirectional charging, but as the answer was short, we didn’t get a lot of specifics on the various forms.

One reason Tesla hasn’t considered bidirectional charging a priority is because there are some reasons that an owner wouldn’t want to use it. For example, if you parked your car with 200 miles of charge and plugged it into the house, then the house or grid decided to discharge your car to take advantage of peak electricity rates (perhaps through Tesla’s Virtual Power Plant program), perhaps you’d be surprised to return to it to 100 miles of range – maybe you made some money, but now you can’t get where you were planning to go.

For this reason, you’d need to have robust controls and internet communications with the car, so that owners can manage demand, but that shouldn’t be hard since every Tesla has internet communications built-in.

The house going dark isn’t really a big concern, though, unless we’re talking about off-grid solar-only houses that use the car as their sole overnight energy storage or something. Otherwise, a home would simply switch to grid power when the car is unplugged. So Musk’s answer was, at best, quite glib.

Baglino also mentioned that there is more value in simply “charging the car at the right time,” rather than sending energy the other way. And this is true – while the dream of using millions of EVs as backup power for the grid is interesting, EVs can already help the grid just by charging at the right time, when excess energy is available, and by not charging at peaks.

Most EVs already do this, because many locations offer “time-of-use” rates allowing EVs to get cheaper electricity at night, which already works well at encouraging owners to charge at night instead of during peak electricity demand And in fact, Tesla even announced that very thing in today’s Investor Day event – they’re offering overnight charging for $30/month in Texas later this year, where their isoated grid often deals with a glut of wind at night with nobody to sell it to, such that wholesale prices occasionally go negative.

But these answers do indicate possible internal tensions over whether to add bidirectional charging capability to cars. This is something that many EV owners like in theory, but could perhaps open a whole can of worms in practice, and may not actually help Tesla to sell all that many cars anyway since it’s a rather small crowd of people clamoring for this feature.

Baglino’s answer showed that the technical capability is there, but Musk’s answer showed that perhaps Tesla still thinks that customers might be too confused or resistant to the idea of losing a certain amount of control over their vehicle and home’s energy usage.