Renault is trying to monetise the parking lot

Renault’s home-battery car is solving the wrong problem

Renault wants the electric Renault 5 to become more than a car. With Mobilize V2G, the car can charge when electricity is cheap, feed power back into the home or grid when prices are high, and supposedly cut charging costs. Renault says the future Renault 5 is its first model with a bidirectional onboard charger. Combined with the Mobilize Powerbox and a Mobilize energy contract, drivers can sell electricity back to the grid. Renault even claims the cost of charging can be cut by half.

Technically, this is real. Strategically, it is much less convincing.

The problem is not that vehicle-to-grid cannot work. It can. The problem is that it depends on the least valuable version of a car: a car that is sitting still.

And yes, today that is most cars. The famous figure is that private cars are parked roughly 95% of the time. That claim is not crazy. Different checks put cars somewhere around 92% to 96% parked. The Netherlands fits that pattern. Dutch passenger cars drove about 122 billion kilometres in 2024, according to CBS. Spread across roughly 9 to 10 million cars, that is around 12,000 to 13,000 km per car per year. At an average driving speed of 40 km/h, that is only about 300 hours of driving per year. A year has 8,760 hours. So the private car is used for motion only about 3% to 4% of the time.

That is the old car problem. We buy a 1,500 kg machine, insure it, maintain it, park it, finance it, and then use it for a few hundred hours per year.

Renault’s idea is to make peace with that inefficiency. If the car is standing still anyway, why not use the battery?

Fine. But that is not a revolution. It is a salvage operation.

Take the Renault 5 E-Tech 52 kWh version. EV Database lists it at about €30,990 in the Netherlands, with a 52 kWh usable battery and about 335 km real-world range. Suppose the owner wants the car to be ready every morning with at least 60% charge. That is a reasonable floor. Nobody wants to wake up and discover their car was busy being a power plant while life decided to happen.

Now suppose the system is allowed to discharge the car down to 20%.

That creates this usable window:

• Battery: 52 kWh
• 60% reserve: 31.2 kWh
• 20% lower floor: 10.4 kWh
• Usable for home/grid: 20.8 kWh

That sounds useful. A Dutch household might use roughly 8 to 12 kWh per day excluding EV charging and heavy electric heating. So the car could cover about two days of normal home use.

But the financial case is thin.

If you move 10 kWh through the car on a given day, your gross value depends on the price spread. If the spread between cheap charging and expensive avoided consumption is:

• €0.10/kWh: €1/day
• €0.20/kWh: €2/day
• €0.30/kWh: €3/day
• €0.40/kWh: €4/day

The full 20.8 kWh usable window is worth:

• €0.10/kWh spread: €2.08
• €0.20/kWh spread: €4.16
• €0.30/kWh spread: €6.24
• €0.40/kWh spread: €8.32

That is before losses, battery wear, charger cost, contract margin, taxes, grid fees, software fees, and human friction.

This is the part that marketing slides conveniently soften. The user has to have the right car, the right charger, the right home, the right parking situation, the right contract, and the right life pattern.

The funnel is brutal:

EV owners → bidirectional capable EV → own driveway or private charger → bidirectional wallbox → smart energy contract → car parked at the right hours → user willing to sacrifice battery margin.

That is not a mass-market business model. That is a niche inside a niche.

The Dutch National Charging Survey 2024 is useful here. Dutch EV drivers still charge mainly at home: 52% of charged kilometres come from a private home charging station, plus 6% from a home socket. But that survey is already among EV drivers, not the whole population. It also shows 80% of EV drivers foresee bottlenecks with two-way charging, especially uncertainty about battery capacity and warranty. That matters. People are not just spreadsheets. They have plans, children, appointments, emergencies and a deep dislike of seeing their car unexpectedly at 23%.

So what is Renault really selling?

Not mobility. Not autonomy. Not a better car business model.

It is selling a way to monetise idleness.

That is understandable. Automakers have a problem. Privately owned cars are expensive per kilometre because the asset is mostly idle. Using the Renault 5 as a rough case: buy it for €30,990, drive it 12,300 km per year for eight years, assume 30% residual value. Just depreciation alone is about €0.22/km. Add electricity at 155 Wh/km and €0.30/kWh, and energy adds about €0.05/km. Before insurance, tyres, maintenance, parking, finance and tax, you are already near €0.27/km.

The machine is not expensive because the electricity is expensive. The machine is expensive because it barely works.

Vehicle-to-grid does not fix that. It just gives the parked machine a side hustle.

And now compare that with the other future.

If cars become genuinely unsupervised self-driving vehicles, the economics invert. A car no longer has to sit outside one household waiting for one owner. It can move. It can serve multiple people. It can reposition. It can earn during hours when a private car would normally be asleep.

A car driving one hour per day at 30 km/h does about 10,950 km per year. That is already close to today’s private car use.

At four hours per day, it does 43,800 km per year.

At eight hours per day, 87,600 km per year.

At twelve hours per day, 131,400 km per year.

That changes the business model completely. The asset cost gets spread across far more kilometres. Utilisation rises. The value of the car shifts from ownership convenience to mobility throughput.

In that world, a car is not valuable because it can discharge 10 kWh into your dishwasher at dinner time. It is valuable because it can move people and goods all day.

This is why the home-battery framing feels strategically backward. It accepts the broken premise of private car ownership, then tries to make the broken premise slightly less wasteful. But if autonomy arrives, the premise changes. The car becomes less like a private appliance and more like infrastructure.

And infrastructure should be used.

There is also a category error here. A home battery and a car battery look similar because both store electricity. But economically they are different animals.

A home battery creates value by standing still. It is installed in one place, wired into one house, optimised for that house’s solar panels, consumption pattern and grid connection. Stillness is the point.

A car creates value by moving. Its battery is there to create range, availability and optionality. Stillness is a failure mode.

So yes, an EV can be a home battery. A laptop can also be used as a doorstop. The question is not whether it can. The question is whether that is the highest use of the asset.

For some people, V2H or V2G will make sense. If you have solar panels, a driveway, predictable driving, dynamic pricing, a compatible car, a cheap bidirectional charger, and a contract that pays properly, there is a case. For fleets parked overnight, maybe stronger. For grid operators aggregating thousands of predictable vehicles, stronger again.

But as a strategic focus for an automaker? It feels like a marketing detour.

Renault should be careful. The future car company is not the company that finds clever ways to make parked cars slightly more useful. It is the company that makes cars radically more useful by increasing utilisation.

The old car sits 95% of the time and becomes expensive per kilometre.

The autonomous car moves far more of the time and becomes cheap per kilometre.

Neither story naturally leads to “let’s hang a €30,000 mobility asset on the wall as a home battery.”

That is the trap. Vehicle-to-grid sounds futuristic because electricity flows both ways. But the deeper future is not bidirectional charging. It is cars that stop being idle capital.

Renault is trying to monetise the parking lot.

The real prize is making the parking lot obsolete.