In the future, the majority of passenger road traffic is likely to be electrically powered. The batteries in all the electric cars on Swiss roads will then have a huge combined storage capacity which it will be possible to tap when the vehicles are parked.
Electric cars use the electricity grid to ‘refuel’. On one hand, the sharp rise in their numbers is increasing demand for electricity and could potentially destabilise the grid if the vehicles are not charged intelligently. On the other hand, private passenger vehicles are usually stationary in parking spaces and only spend a fraction of their time being driven. With bidirectional charging technology, electric vehicles are able not only to draw electricity from the grid, but also to feed it back in. They become power banks that can reduce strain on the power supply when needed. After Fukushima, for instance, Japan’s government obliged the country’s car manufacturers to ensure that electric vehicles are equipped for bidirectional charging: This has been a standard feature of Japanese cars for 10 years, such that the energy stored in vehicle batteries can be accessed during times of crisis.
Bidirectional charging is firstly only possible if the vehicles and charging stations are technically equipped for it. Secondly, there also has to be Internet-based automated communication between the charging station and the electricity grid operator so that the requirements of each can be coordinated on the basis of the battery capacity made available by the vehicle owners, and to control when charging or discharging takes place. In this way, electric cars can provide flexibility via their batteries, in order to compensate for load peaks on the electricity grid and to optimise internal consumption for locations with solar power systems. The effect is magnified if many vehicles’ storage capacities are used in a coordinated manner. The V2X Suisse pilot project aims to demonstrate the potential of bidirectional charging in Switzerland and to identify the players for which it could offer a profitable business model. The project is led by the car-sharing provider Mobility, while car manufacturer Honda, software developer sun2wheel, charging-station developer EVTEC, aggregator tiko Energy Solutions and knowledge-transfer society novatlantis are involved as scientific advisers. Marco Piffaretti, Project Manager at Mobility and President of sun2wheel, is convinced that “what is needed here, is close, cross-sector cooperation between various specialists who are willing to bring their know-how to the table and solve a problem together”.
This pilot project involves 50 of Mobility’s bidirectional electric vehicles at 40 locations throughout Switzerland. These will make their combined battery storage available to stabilise electricity grids when they are not being driven. First and foremost though, the vehicles must be available, and sufficiently charged, when customers want to use them. This is achieved with newly developed software, which uses the bookings in the reservation system to calculate and update the vehicles’ required charge and free battery capacity for the next two days every fifteen minutes with to-the-minute accuracy. The free capacity is offered to the transmission grid operator Swissgrid, to the local grid operator or to a solar power system operator at the vehicle’s location. In the future, this system could be transferred to other fleets of company vehicles with a central booking system, or to private vehicles that offer part of their storage capacity on a platform.
The ongoing V2X Suisse project has already yielded initial findings: It has been shown that cooperation between the various partners does work quickly enough for the system to aid management of the Swiss transmission grid. Furthermore, it does seem possible to obtain a financial return from providing vehicle batteries’ flexible storage capacity on the energy market. However, for any statement to be made about the conditions under which bidirectional charging is most economical, more experience needs to be gathered between now and the end of the project.
The conditions under which this project is conducted are actually quite difficult, because Mobility’s shared vehicles spend much less time at a standstill than private vehicles. This means that if any benefit can be generated here, the system should work for all electric cars in Switzerland. These are set to keep growing in number: The industry expects there to be 2.4 to 2.9 million vehicles by 2035, the combined storage capacity of which equates to more than a third of the maximum energy content of all the country’s pumped-storage power plants.
If bidirectional charging is to catch on, it is “time to seriously discuss the development of this technology in Switzerland and to quickly set about adapting the relevant regulatory framework conditions,” says Stefan Dörig, Head of Regulatory and Public Affairs at tiko Energy Solutions. Today, battery storage is at a disadvantage compared to pumped-storage power plants, for example, because the latter do not have to pay grid-usage fees for the pump energy. A consolidation bill revising the Energy Act and Electricity Supply Act has partly eliminated this inequality, but there is still a lack of clarity regarding implementation of the provisions. In general, the structure of the national electricity system, with over 600 grid operators, makes Switzerland-wide implementation of innovative solutions like bidirectional charging very challenging.