Electric vehicles are more than just a means of transport—they can also be power sources.
In this interview with electrive, Frank Spennemann from Mercedes-Benz explains how bidirectional charging works, its benefits, and the challenges ahead.
The interview was conducted by Carla Westerheide, electrive.
Dr. Frank Spennemann (Mercedes-Benz Mobility AG): This question will likely be answered in the next 5 to 10 years. Currently, we see both AC and DC bidirectional charging. Around 80% of manufacturers start with DC because it has certain technical advantages. It’s more easy to connect it with the grid. If you feed the grid you have to comply with so called grid codes, which are defined by the grid operator.
With DC, the wallbox ensures grid compliance. With AC, compliance is split between the car and the wallbox, making it more complex. Some countries are still defining how AC bidirectional charging should work. My gut feeling is that we will see more DC solutions in the beginning.
Mercedes-Benz has already been offering bidirectional-capable cars in Japan for several years because there is a clear standard (CHAdeMO). All EQ models (EQE, EQS, EQB, EQA) in Japan support bidirectional charging.
We believe interoperability is key, meaning that bidirectional charging must be based on a standard. The relevant standard is ISO 15118-20, released about 1.5 years ago. All OEMs and wallbox manufacturers are working on implementation, and we are doing the same. Our next generation of EVs will be bidirectional-capable.
As mentioned we intend to introduce it with the next generations of our vehicles and you will see when they hit the market.
As a car manufacturer we have the bidirectional capability of the vehicle. Of course we do this because we see the tremendous value:
1. Energy Independence & Backup Power:
2. Financial Benefits of V2G:
3. Supporting the Energy Transition:
The main topic is, that we have to have a product which the costumer is willing to take. Therefore you have to have the financial benefit.
Regulatory Challenges: In Germany, there is a so-called double taxation issue—when energy is stored in the car and later fed back into the grid, customers are taxed twice. This eliminates the financial incentive and must be addressed.