With so-called bidirectional charging, vehicles absorb excess and therefore cheaper solar and wind power from the grid during the day and feed it back in in the evening or at night.
The Fraunhofer Institutes for Solar Energy Systems (ISE) and for Systems and Innovation Research (ISI) have examined the cost advantages that this two-way charging could bring for network operators and consumers on behalf of the EU interest group Transport & Environment (TE). of all things.
Accordingly, in the most advantageous scenario, the extensive use of electric cars as electricity storage would reduce the investment requirement in the European energy network by more than 100 billion euros between 2030 and 2040. To achieve this, however, around half of all electric cars and battery trucks would have to be able to feed electricity back in by 2030. If this flows directly into the overall network, it is called vehicle to grid (v2g, i.e. from the car to the network).
Electricity for household
Owners also have the option, especially in single-family homes, of using the electricity stored in the car battery for their own household (vehicle to home, or v2h). The electric car could then become an energy supplier in the particularly energy-intensive evening hours and reduce electricity costs. It then charges again at night when demand is low and electricity is cheap.
In Germany, savings of more than 700 euros per year would be possible in this way for a four-person household, the study authors calculated. If it is fed into the overall network, any remuneration for the wagon keepers would also be incurred.
Some obstacles
But there are some obstacles to the widespread distribution of two-way technology. On the one hand, there is the problem with electricity conversion. When charging electric cars, the alternating current in the network must be converted into direct current and vice versa. On some models this happens in the car. Others require a more expensive wallbox to connect the car to. The study authors recommend a uniform standard that manufacturers can adapt to.
There was also a lack of regulatory and political framework conditions to make the previous niche technology marketable on a large scale. At an industry meeting a few days ago, German Economics Minister Robert Habeck (Greens) announced that bi-directional vehicles and services could be commercially available from 2025.
“As mobile electricity storage devices, electric cars can make an enormous contribution to stabilizing the electricity system,” said Habeck. “Their batteries can be used to temporarily store electrical energy, thereby creating additional flexibility.”
ePaper
**Interview with Dr. Anna Müller, Energy Systems Analyst at Fraunhofer ISE**
**Editor**: Thank you for joining us today, Dr. Müller. Your recent study with Fraunhofer Institutes has highlighted some compelling benefits of bidirectional charging in electric vehicles. Can you explain how this technology works and its potential impact on both network operators and consumers?
**Dr. Müller**: Certainly! Bidirectional charging allows electric vehicles (EVs) to not only draw power from the grid but also send electricity back to it. During the day, when solar and wind power generation peaks, EVs can absorb excess energy at a lower cost. Then, in the evening, they can discharge that energy back into the grid when demand is higher, effectively acting as mobile energy storage. Our study indicates that if implemented on a large scale, this could save network operators over 100 billion euros in infrastructure investments by 2040.
**Editor**: That’s a significant amount! What does this mean for households, particularly those with electric vehicles?
**Dr. Müller**: For households, particularly single-family homes, this technology could represent significant savings. Our analysis suggests that a four-person household could save over 700 euros annually by using their EV battery to power their home during peak hours. This ‘vehicle to home’ (v2h) capability could not only help reduce electricity bills but also provide a more stable and efficient energy source at times of high demand.
**Editor**: There seem to be several advantages, but your study also identified some obstacles. Could you elaborate on what challenges exist for the widespread adoption of this technology?
**Dr. Müller**: Yes, there are a few key challenges. First, there are technical hurdles related to electricity conversion. Electric vehicles need to convert AC from the grid to DC for storage and vice versa. While some newer models have built-in converters, others require additional infrastructure, like a specialized wallbox, which can be costly. Furthermore, we need a standardized system that manufacturers can adopt to simplify the installation and usage across different models.
Additionally, there’s a lack of robust regulatory and political frameworks to support the transition to bidirectional charging. Recent statements from German Economics Minister Robert Habeck indicate a movement in the right direction, with hopes that these technologies may be commercially viable by 2025.
**Editor**: What role do you see electric vehicles playing in the future energy landscape?
**Dr. Müller**: Electric vehicles have the potential to play a transformative role as mobile electricity storage devices. By providing a means to balance energy supply and demand, they can help stabilize the electricity system. This is particularly crucial as we shift towards more renewable energy sources which can be intermittent. If we harness this technology effectively, we could also reduce our reliance on traditional power plants and contribute to a greener, more sustainable energy future.
**Editor**: Thank you, Dr. Müller, for your insights on this pioneering technology. It seems the future of transportation and energy is closely interconnected.
**Dr. Müller**: Thank you for having me! It’s an exciting area of development, and I look forward to seeing how it evolves.
