Power in, power out: When the car becomes a power plant

02.06.2025

Whether in Japan, the UK or California: Electric vehicles are increasingly feeding electricity back into the grid. The technology for this is called bidirectional charging. Find out more about the latest developments around the globe.

Electric cars that not only charge electricity, but also supply it again when required: The concept behind this is called bidirectional charging – often referred to as V2X (vehicle-to-everything). In this article, we show which regions of the world are leading and particularly innovative in the field of V2X.

Japan: Emergency power as a national responsibility
United Kingdom: Europe’s V2 G pioneer
California: V2X soon to be enshrined in law?
France: Technology meets centralism
Switzerland’s population density of Small, complex – but ready

Japan: Emergency power as a national responsibility

Following the Fukushima disaster in 2011, bidirectional charging took on a whole new role in Japan. Vehicle-to-Load (V2 L) technology, in which the car supplies appliances or households in the event of a power failure, was strongly promoted. “In Japan, cars have been equipped with bidirectional as standard for over ten years. This alone shows that it is not a major challenge from a technological point of view,” explains Marco Piffaretti, energy expert and pioneer of electromobility in Switzerland.
Although the Japanese government has not introduced a V2 L obligation, the impetus came from the very top: “Obviously, the emperor personally asked Japanese car manufacturers to upgrade their vehicles,” says Piffaretti. Today around 15,000 V2H systems are in use in the country, primarily as emergency power generators. By contrast, feeding back into the public grid or optimising self-consumption with PV systems has so far hardly been widespread in Japan.

The following V2 terms are used

V2H (vehicle-to-home)
Electric cars capable of bidirectional charging can not only store electrical energy for driving purposes, but also feed it back into the home. Vehicle-to-home enables you to supply your own home with the stored electrical energy from an electric car. The entire charging and recovery process takes place behind the house’s electricity meter and is often used to increase the self-supply rate for homes via photovoltaic systems.
V2B (vehicle-to-building)
As with vehicle-to-home, electric cars capable of bidirectional charging can not only store electrical energy for driving purposes, but also feed it back into a building with multiple consumers. Vehicle-to-building can be used to supply an apartment block or commercial/industrial units with the stored electrical energy from an electric car, often as part of an electric car fleet. Peak shaving can also help to mitigate usage peaks within the building. The entire charging and recovery process takes place behind the building's connection to the grid.
V2G (vehicle-to-grid)
Electric cars capable of bidirectional charging can not only draw electrical energy from the grid, but also feed it back in as part of an intelligent energy system. This process is managed using signals from the distribution or transmission network operator and can take place both at public charging stations and within buildings via the grid connection. V2G charging and discharging of a larger number of electric cars (pooling) count as services in energy trading and for stabilisation within both the distribution and transmission networks. Vehicle-to-grid thereby enables intelligent sector coupling.
V2X (vehicle-to-everything)
V2X is used as an umbrella term for all the above applications, as well as the combined application of multiple types. For example, electric cars capable of bidirectional charging parked in a large property’s car park can be used both for self-consumption optimisation and peak-shaving purposes (V2B), as well as to serve the grid (V2G). The autonomous supply of individual consumers and island grids, and the charging of other electric cars, completes the spectrum.
V2 L (vehicle-to-load)

United Kingdom: Europe’s V2 G pioneer

The UK is one of the most active countries in Europe when it comes to vehicle-to-grid. Around 120 pilot projects are underway on the island – more than anywhere else on the continent. “The UK is very strong in the area of pilot projects. This shows that the country has recognised the potential and urgency of this technology,” says Marco Piffaretti.
One reason for this drive to innovate: From 2030, no new combustion engines will be allowed to be sold in the UK. The British energy industry is therefore intensively testing how electric vehicles can be integrated into the grid as flexible electricity storage systems. “Distribution system operators have learned how to regulate in the electricity grid. This creates a win-win situation,” explains Piffaretti. The political will seems to be there, irrespective of changes of government.

Charging an electric car in Switzerland: It’s as easy as that

Never charged an electric car? No problem – we’ll show you what to do. In this video, you will learn how to find the right charging station, how long it takes to charge, which connector you need – and how to operate the station confidently and stress-free.

California: V2X soon to be enshrined in law?

California is also one of the regions with particularly ambitious climate targets. From 2035, only emission-free vehicles may be sold there. A law has already been passed that allows the authorities to prescribe the use of V2 G technology in electric cars – even if it has not yet been implemented. This could make California the first place in the world where bidirectional charging is mandatory.
The American approach differs significantly from that in Europe or Asia: The focus is on integration into the congested California power grid – especially in light of frequent heat waves and power outages. V2X is not only seen as the technology of the future, but also as a strategic element of security of supply.

csm_Mobility-Infografik-V2X-bidirektionales-Laden-DE

26/06/2024

Bidirectional charging: the future of e-mobility explained

Find out more about the terms Vehicle-to-Home, to Grid, to-Building, to-Load or to-Everything here.

To the info page

V2X-Honda e-Drohne_mobility-carshariing_2022

V2X

V2X SUISSE: A look back at the Mobility pilot project

Mobility’s “V2X Suisse” came to an end in 2024: Here are key questions and answers about Switzerland’s biggest trial to date.

To the info page

19/06/2024

Questions and answers on the “V2X Suisse” project

France: Technology meets centralism

France is also taking a pragmatic and ambitious approach. Car manufacturer Renault has launched several V2 G projects and equipped the new Renault R5 E-Tech Electric with bidirectional technology from the outset. “There are a number of exciting projects in France – some of them in cooperation with large power plants,” explains Marco Piffaretti.
One advantage of the centrally organised country: France has only one distribution system operator, which simplifies the national roll-out of such technologies. “In Switzerland, this takes up to 600 individual agreements!,” continues Piffaretti. The R5 is offered in combination with a bidirectional charging station, power contract and smart energy management app as a complete package – a model that could set a precedent.

Switzerland’s population density of Small, complex – but ready

The Electricity Act, which was passed on 9 Adopted by the Swiss people on June 2024, improves the framework conditions for economic operation. It enables, for example, the reimbursement of double grid fees and the creation of a flexibility market for local distribution grid operators. However, it will take a few years for other factors to improve and for the technology to become widely accepted.

Even though Switzerland has some catching up to do for structural reasons, something is happening: As part of the “V2X Suisse” project, Mobility and its partners tested bidirectional charging with 50 Honda e-vehicles. The field trial was successful: The technology works, profitability is within reach – provided the regulatory conditions are right. One structural obstacle remains: “We have the highest rate of tenants in Europe,” says Piffaretti. “Tenants usually can’t decide whether to install a solar system on their house or set up an electric charging station in the garage.”

But there are rays of hope. Property owners have high purchasing power and thus the potential to implement innovations. Piffaretti also sees major opportunities in the area of fleet vehicles: “The potential is huge, especially for companies that have a lot of trucks on the road. These stand still at night and on Sundays – ideal for bidirectional charging,” says the expert. The fact that Mobility could also play an active role in establishing bidirectional charging technology in the future has become clear since the “V2X Suisse” project at the latest.