V2H: Why the real debate isn't the one you're being presented
I've been driving electric for ten years. Not out of proclaimed conviction, but out of real conviction. And when people talk to me about Vehicle-to-Home (V2H) as an energy revolution, I don't react like an enthusiastic early adopter. I react like someone who knows what it's like to leave in the morning with 15% battery because the system had "optimized" charging the night before.
The dominant debate revolves around return on investment: savings on the electricity bill, arbitrage between peak and off-peak hours. It's the wrong question. Not because money doesn't matter, but because this economic framing overlooks the only angle that would truly justify V2H: ecology. And when you honestly examine this angle, the conclusions are much more nuanced than what the industry presents.
The economic argument: insufficient and fragile
The commercial argument is well-known: use your EV's battery to power your home during peak hours, reduce your bill, pay off your installation in a few years. The most optimistic studies talk about savings of around 250 CHF per year over 15 years.
250 CHF per year. For bidirectional equipment that costs between 3,000 and 8,000 CHF to install—and whose current 10 kW bidirectional chargers sometimes reach much higher sums when including electrical compliance. I've done the math. Several times. It doesn't add up.
The energy transition deserves better than fragile economic arguments. I believe in EVs, PV, renewables. Precisely for this reason, I refuse to see them sold with approximate ROI figures. When the numbers shift slightly, support collapses. Ecology shouldn't need to justify itself through the electricity bill.
The real problem lies elsewhere: we're evaluating the wrong criterion. An EV battery isn't a financial investment. It's a physical resource with a carbon manufacturing cost, a lifespan in cycles, and availability that no one truly controls. My car doesn't know when I'll need it. No algorithm does either.
The ecological argument: the only one that really matters
The only ecologically relevant question is this: does V2H avoid the manufacturing of an additional battery?
The traction battery already exists. Its carbon manufacturing cost is real and significant, but it's already there, in the vehicle. If this battery can also serve as a domestic energy buffer without installing a second stationary pack, we avoid producing additional equipment. This is the only V2H argument that truly holds.
According to life cycle analyses of stationary LFP storage, using a fixed battery adds an average of 25.6 g CO2-eq per kWh of stored electricity over its operational lifespan. If V2H genuinely makes this unnecessary, the theoretical carbon benefit becomes tangible.
But this argument has a condition that no one clearly states: it assumes the vehicle is available when the system needs it. On sunny days with maximum PV production, you might be out. On evenings of peak consumption, the vehicle might be elsewhere. This correlation between vehicle availability and energy needs doesn't appear in any serious study. Because it's uncomfortable.
The Swiss grid mix: an argument that changes everything
One marketing argument deserves deconstructing: "injecting your PV surplus into the grid is wasteful, better to store it in your EV."
In Switzerland, this is false.
The Swiss electricity production mix is about 60% hydropower, historically complemented by nuclear. Injecting PV into this grid wastes nothing. The energy is consumed elsewhere, by someone else, instead of a more carbon-intensive source. The grid is a collective buffer. The electricity you inject displaces fossil consumption somewhere in Europe.
This argument would hold in a context of a highly carbon-intensive grid (Germany during hours of high PV production, some US regions). Not here. In Switzerland, "avoiding grid injection" isn't an ecological argument. It's marketing.
The constraint no one models
Here's what V2H studies don't model: my car doesn't know when I'll need it.
A static buffer doesn't care. It's there, plugged in, available 24/7. The car must simultaneously be parked, plugged in, and sufficiently charged so the system doesn't leave you stranded at departure. These three conditions must align. In real life, that's not guaranteed.
To work around this, V2H systems define a guaranteed minimum SoC (State of Charge), typically 20 to 30% of capacity. On a 60 kWh battery, you're left with 20-25 kWh actually usable for the house. The argument "my 60 kWh battery replaces a 10 kWh static buffer" collapses in practice.
The deeper problem is statistical. The times you'd need V2H most (cold nights, consumption peaks, prolonged bad weather) don't necessarily coincide with vehicle presence. I use my EV. Really. And that's precisely why V2H doesn't work for me, nor for most active users.
No one publishes this correlation. It's household-specific and hard to generalize.
Conclusion
V2H is an ecologically coherent concept in one specific case: where it avoids manufacturing an additional stationary buffer, in a household where the vehicle is mostly stationary, in a region with a carbon-intensive grid.
This profile exists. But it's a minority among those being sold V2H.
For an active EV user in Switzerland, the balance is different. The grid is clean. The vehicle is used. The installation cost of a certified bidirectional system far exceeds that of a small stationary LFP pack, available 24/7 without mobility constraints.
The real debate about V2H isn't "how much will I save on my bill". It's "does this system truly replace something that would've needed manufacturing, and does my usage profile allow it to deliver on this promise?"
For most Swiss households with an active EV, the honest answer is no.