The Renault 5 E-Tech can halve your electricity bill thanks to V2G

The electric Renault 5 E-Tech has just been made official. But she doesn't arrive alone. It will be the first electric car in France to offer bidirectional V2G charging. According to Renault, this will allow to divide the electricity bill linked to the cost of recharging by two. We spoke with an engineer in charge of the project and obtained some interesting first figures.

The electric Renault 5 E-Tech, unveiled in Geneva on Monday, February 26, 2024, is one of the electric cars that will mark the year 2024. It has many advantages, starting with its entry-level price, around 25,000 euros. We were also able to get on board to get a first impression.

But, the electric R5 will revolutionize the uses of electric cars in France, thanks to a functionality new to the French market, and extremely rare worldwide. This is bidirectional V2G ( vehicle-to-grid ) charging which allows the electricity network to be supplied using the car's battery.

A sort of reverse charging, different from the V2L ( vehicle-to-load ) function, also present on the Renault 5 E-Tech, which allows electrical equipment (barbecue, fridge, etc.) to be powered with the car battery, and much more widespread.

The good news is that this bidirectional V2G charging will allow customers to reduce the cost of their monthly electricity bill , by receiving income linked to resale. Renault announces that in France, “  these revenues could correspond to around 50% on average of the cost of home charging” .

What is V2G two-way charging?

If you are not familiar with V2G technology, a quick explanation is in order. This functionality, which is not available on the less powerful engines of the electric R5, requires a special terminal, developed by Mobilize , a Renault subsidiary. This terminal allows you to recharge the car as well as to “unload” it, to send the electricity to the electricity network.

The idea is simple for the customer: recharge the car battery when energy costs the least and is least carbon-intensive, then reinject energy into the national electricity network, in the opposite case. This allows the energy supplier to use the electricity contained in customers' batteries instead of buying it from a producer at too high a price. And to thank the customer, the energy supplier will remunerate the latter , as if he were an electricity producer.

We therefore come to our second prerequisite: the V2G function requires subscribing to a contract with a partner electricity supplier. In the case of the Renault 5 E-Tech, it is The Mobility House for France. If you are with EDF, you will have to change supplier to be able to benefit from the V2G function . Otherwise, you can of course always recharge the car.

If you have a V2G compatible car (like the electric R5), a V2G terminal and a special electric subscription, then you are on track. In the case of The Mobility House, the partnership with Renault and Mobilize makes it possible to make the function completely autonomous, via the application dedicated to the car.

And in practice?

Here's how it will happen in practice: you arrive home, and you plug your Renault 5 E-Tech into the Mobilize terminal. You will have previously indicated in the dedicated application the desired recharge rate (for example, 80%) at a specific time (for example, 8 a.m.). You will also indicate how much minimum autonomy you wish to maintain at any time of the day and night. Thus, the terminal will not be able to discharge the battery more than this indicated level, in order to have sufficient autonomy in all situations .

Then the terminal will live its little life, and will decide, according to the price conditions of the spot electricity market , whether it is better to recharge the car immediately, whether it is better to wait, or whether, on the contrary, it is appropriate to send energy into the network. A type of trading. Then, the car will be recharged, to be ready to hit the road again at the scheduled time. If necessary, it is of course possible to override the system , and “force” the full supply of electrons directly, by deactivating the V2G function.

But be careful, because Mobilize has chosen a somewhat surprising system. The customer is paid by The Mobility House, not according to the quantity of energy he sends back to the electricity network, but according to the monthly duration of connecting the car to the terminal , expressed in hours.

Thus, a customer who plugs in his car 450 hours per month (15 hours per day) will receive remuneration linked to the resale of energy twice as high as another customer who only leaves his car plugged in 225 hours per month (7.5 hours per day). day). The problem is that Renault has refused, for the moment, to indicate the purchase price of electricity.

What gain in practice?

What we officially know is that “  this contract guarantees to supply this electricity at a rate as competitive as the market reference price ”. As a reminder, the price per kWh of the regulated tariff has increased to 0.2516 euros since February 1, 2024. Which gives a cost per 100 km of 4.5 euros for an electric car which would consume 18 kWh / 100 km.

We can drastically lower this price with the EDF Tempo or EDF ZenFlex offers , allowing you to travel 100 km for 2.3 euros. Compare with the minimum 10 euros charged to travel this distance by petrol car.

But for the resale of electricity, we do not know how much The Mobility House will remunerate the customer. We asked the question at the Geneva Motor Show to Ziad Dagher of Mobilize, in charge of the project. The man kicked in by taking up the elements of official language. But that was without counting on the launch of the page dedicated to the R5 on the Renault website.

The Renault website has spoken

In the charging section, we finally know how the 50% reduction in the cost of home charging was calculated . The small line tells us that this hypothesis reflects the “estimated cost of home charging for a person recharging the equivalent of 10,000 km per year at home, at the current regulated rate, with an estimated consumption of 16 kWh / 100 km. V2G gains calculated for an average connection time of 15 hours per day.

Some details: the consumption of 16 kWh / 100 km is quite consistent, since the Renault Zoé , with a battery of capacity equivalent to the Renault 5 E-Tech and a close autonomy, is given for a WLTP mixed consumption of around 17 kWh / 100 km. With peri-urban use, we can therefore expect to slightly lower this consumption. On the other hand, on motorway journeys, expect to exceed 20 kWh / 100 km.

The annual mileage (10,000 km) seems consistent for a compact car since it does not take into account public charging. As an indication, the average annual mileage, all categories of car combined, was 12,000 km before the pandemic, and around 11,000 km in 2021.

Finally, the connection time of 15 hours per day means that it will be unplugged (and therefore outside the house) for 9 hours. Which is more or less in line with a typical working day.

Our calculations

If we do our little calculations, 10,000 km traveled with a consumption of 16 kWh / 100 km and an electricity tariff gives us a total annual cost of 402 euros. Dividing this cost by two allows you to save 201 euros per year and to have a cost price of 201 euros for 10,000 km. Or 2 euros per 100 km. Not bad, given the low constraints required by the system.

We can deduce that one hour of connection reduces your electricity bill by 0.367 euros. In the case where the driver drives less than 10,000 km per year, and the car remains plugged in for longer than 15 hours per day, we can therefore further reduce the bill.

But be careful, because this solution requires additional costs initially. You must in fact purchase a terminal that integrates more advanced power electronics. Mobilize did not wish to tell us the price of the bidirectional terminal, but its 22 kW unidirectional version costs 1,500 euros with installation , if the car is purchased at the same time.

This is a fairly attractive price, because one of the cheapest 22 kW terminals on the market, the Tesla Wall Connector , is sold for 535 euros, without installation. With installation by a certified professional, it easily climbs to 1,500 euros, even if the tax credit ( which increased from 300 to 500 euros in 2024 ) may reduce the final bill.

Is it profitable?

The Mobilize terminal will therefore be profitable for 7 and a half years under the assumption of mileage and consumption adopted by Renault. But another solution could be even more interesting. If you subscribe to an EDF Tempo offer , you can pay 0.1296 euros per kWh depending on the days of the year and time of day. Which gives 207 euros to travel 10,000 km, or 2 euros for 100 km. Which is almost the same as with the bidirectional charging of the R5.

But the big difference is that EDF Tempo requires “work” from the customer. You must in fact recharge your car only during “super off-peak” hours (blue days) to benefit from this rate. Otherwise, the bill will be higher (3 euros / 100 km) or even very steep during peak hours, on red days (12 euros / 100 km).

In other words, Renault's solution is much more comfortable for the customer . But, for large energy consumers, who have other electrical appliances (heat pump, oven, hobs) and whose uses can be deferred, the EDF Tempo or ZenFlex solution may be more financially attractive.

In other words, Renault's solution is much more comfortable for the customer . But, for large energy consumers, who have other electrical appliances (heat pump, oven, hobs) and whose uses can be deferred, the EDF Tempo or ZenFlex solution may be more financially attractive.

A difficult choice

In the end, we are still missing a few elements to know if this offer will really be relevant and financially interesting for customers. We do not know in detail the cost of the kWh billed to the customer, nor the cost of buying back the hour during which the car is plugged in. Even if we were able to get a fairly precise idea with these first data.

But it is clear that the comparison with traditional electricity offers will be difficult. We imagine that this is why Mobilize wants the customer to be paid for the time of connection and not for the quantity of energy returned to the network. Because the latter is variable, depending on the needs of the network at the national level. But when energy prices soar, the customer could be paid more with this solution .

This is what Tesla has chosen to do in the United States, with its virtual power plants . It's the same operation as at Renault, except that the car is replaced by solar panels, and that the remuneration is based on the quantity of energy sent back to the network. In other words, customers who have solar panels and a Tesla Powerwall battery can sell their energy back to Tesla Energy, an electricity supplier . With a cost decided on a case-by-case basis, which varies every day.

An offer that can save the electricity network

Mobilize nevertheless told us that the offer could evolve, and that it could be possible, in the future, to remunerate the customer according to the quantity of energy drawn from their battery. However, some questions remain unanswered, such as whether the R5 will be able to do V2H, to power the house (and not the neighborhood electricity network), in the event of a power outage for example. Like the Tesla Cybertruck does with PowerShare functionality . We are awaiting the response from the French manufacturer.

Let's end on a positive note that will give pause to those who think that the electric car is a huge mistake and that it will bring the electricity grid to its knees in winter . The V2G function allows you to avoid this. Imagine a harsh winter evening, with negative temperatures across France. It’s 7 p.m., you get home with your electric R5 and you plug it in. You will turn on the heating, the oven and the hobs to cook food.

You are not alone, because 100% of French people now drive electric, and are hungry at 7 p.m. Precisely, V2G will delay the charging of your car (and potentially that of your neighbors), precisely to avoid a blackout. And in the worst case scenario, if there isn't enough electricity flowing through the grid to power all the homes, cars will take over a nd will become, in a way, a virtual power plant.