Bidirectional charging project: "We are sending a strong signal to car manufacturers"

Mobility has carried out the largest practical test involving bidirectional electric cars to date and has come to the conclusion that this technology works and could be used in a financially viable way. Having been approved by popular vote, the Swiss Electricity Act [Stromgesetz] also provides more favourable regulatory conditions in Switzerland. But to enable electric cars to stabilise the power grid on a large scale in future, politicians, car manufacturers and network operators will need to do more still.


  • Mobility

The era of bidirectional electric cars is just around the corner, but it will be a few more years before the technology is widely deployed. This is the greatly oversimplified conclusion of Mobility’s V2X Suisse pilot project. Over the course of a year and a half, the car sharing company has operated and tested 50 bidirectional electric cars as part of its fleet – in collaboration with six partners and with the support of the Swiss Federal Office of Energy (see box). Not only did the cars draw electricity, but they also returned it to the grid when needed. Expectations for this technology are high, as electric cars could help stabilise the power grid in the future. After all, just a few thousand bidirectional cars can provide the same power output as a pumped-storage power plant.

Car sharing is complex

Now that the project is over, the those in charge of it are able to draw a definitive – and positive – conclusion. Firstly, the system’s technology worked and, secondly, it was proven that the cars supply electricity in seconds when the corresponding signal is given by the grid operator. The V2X project has shown for the first time that it is possible to group together multiple electric cars to create a virtual storage system and control the flow of energy in real time. With its vehicles and infrastructure, Mobility provided the perfect environment for this test. “This allowed us to investigate what is probably the most complex use case of all – with cars stationed all over Switzerland with different electricity providers and having to be available for shared journeys at any time,” said Pascal Barth, an electrical engineer at Mobility. According to Pascal, this goes to show that, “if bidirectional charging is possible in the case of car sharing, it should be possible anywhere”.

To be financially viable, prices have to fall

In addition to technical feasibility, the project also investigated whether a bidirectional fleet of cars could make money. The short answer is no, or at least not yet. First, the economic conditions for grid services need to be more favourable. V2X Suisse has discovered that it is already possible to generate revenue by charging and discharging at the right time – up to 600 Swiss francs per vehicle per year. However, this was far from enough to cover costs during the test phase. This is partly due to the very high prices for bidirectional charging stations. In addition, there are still very few bidirectional electric cars available and a lack of interoperable standards.

As it stands, fleet management therefore requires specific solutions that are not compatible with other car brands or charging stations. 
“The range of cars with bidirectional charging has not developed as quickly as hoped,” said V2X project manager and industry expert Marco Piffaretti. Nevertheless, he remains optimistic: “V2X Suisse has generated a lot of positive reactions and boosted bidirectional technology. We are sending a strong signal to car manufacturers to bring more of these vehicles to market at lower prices.”

No more double grid fees from 2025

Nevertheless, the regulatory framework is set to become significantly more favourable from 2025 onwards, as the Swiss electorate approved the Electricity Act on 9 June. This makes it possible, for example, to reimburse the double grid fees that have hitherto made feeding electricity back into the grid financially unattractive. In addition, the Act lays the foundations for a flexibility market for local distribution network operators. The corresponding ordinances are now being drawn up by the Swiss Federal Administration.

Mobility focusing on intelligent charging

In a few years’ time, it will be possible to operate a decentralised fleet of electric cars in a way that serves the grid and, above all, is cost-effective. Until then, Mobility will put bidirectional charging on the back burner and focus on the ongoing electrification of its fleet. The company has already switched 600 of its 3,000 or so shared cars to electric drive systems – including charging stations – and is still forging ahead with this transition. “The V2X Suisse project was a great opportunity for us to learn a lot about developments and technologies in electromobility and the energy markets,” says Mobility CEO Roland Lötscher. “We will use the findings to charge our electric fleet more intelligently in the future. Not only will this have a positive financial impact, but it will also improve the service life of the car batteries.” He believes it is entirely possible that Mobility might return to bidirectional charging in the future: “V2X Suisse is an impressive demonstration of the potential of this technology for Switzerland and for fleet operators.”


Seven companies are involved in V2X Suisse, with Mobility as the project lead. Also involved are:, a car manufacturer (Honda), a software developer (sun2wheel), a charging station developer (EVTEC), aggregators (tiko) and scientific support (novatlantis, in collaboration with ETH Zürich). The project is supported under the pilot and demonstration programme run by the Swiss Federal Office of Energy (SFOE). The final report will be publicly available from late summer in the Swiss Federal Government’s ARAMIS database:

You can find more information here.

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