© istockphoto.com/rclassenlayouts
Electric cars as virtual power stations
In order to advance research and development in this field, the Federal Ministry for Economic Affairs and Climate Action is providing €80 million to support electric mobility and its integration into the electricity markets, with a focus on bidirectional charging.
„We are giving targeted support to research and development in this field so that bidirectional charging can become a reality as soon as possible. Our aim is to make Germany the lead market and lead provider of electric mobility and its integration into the electricity grid,“ says Michael Kellner, Parliamentary State Secretary at the Federal Ministry for Economic Affairs and Climate Action.
More storage capacity than all the pumped-storage power plants together
The fact is that, taken together, electric cars already have more storage capacity than the combined total of all the pumped-storage power plants. And the same amount of storage capacity will be added each year over the next few years. Also, electric cars are parked 96% of their time and thus offer ample capacity to serve as a storage medium via bidirectional charging. They are connected virtually by aggregators. In this way, electric cars can contribute to stabilising the grid, for example when more energy is produced than can be consumed at the time, or can act as a reserve at times of high electricity demand and to stabilise the grid.
How bidirectional charging works
Bidirectional charging is a novel charging technology which permits electricity to flow in two directions. In normal (unidirectional) charging processes, the electricity flows from the charging station to the electric vehicle’s battery, i.e. only in one direction. In the case of bidirectional charging, the electricity can also flow back from the battery via the charging station into the grid. The car battery then serves as an efficient storage medium.
Good for the energy transition, good for grid stability
So wind turbines would no longer have to be switched off when there is a surplus of energy, but could continue to operate and generate green electricity. Thanks to bidirectional charging, what was previously “surplus” energy would be charged in the batteries of the electric vehicles as a buffer, and stored there for the time being. In times when less energy is available, this energy could then be returned to the public grid.
Car-owners benefit from bidirectional charging
Owners of electric cars can benefit personally from bidirectional charging. In the simplest case, the electric vehicle can replace or expand a home storage facility for the owner’s own PV equipment so that renewable electricity generated at home can be fed back into the home’s own system later (when the sun has stopped shining). Where vehicle fleets feed the stored electricity back into the general electricity grid, it may even be possible for households to benefit from an extra source of income. From next year, car-makers intend to sell their first cars which support bidirectional charging.