Imagine a future where storms and bad weather are no longer a cause for power outages, a future where an electric vehicle (EV) can power the home and keep the lights on when the grid fails
What sounds futuristic is already possible thanks to bidirectional charging. The concept is simple: electricity flows not only from the grid into a vehicle’s battery, but also from the car back into homes (vehicle-to-home, V2H), the wider grid (vehicle-to-grid, V2G), or even commercial buildings (vehicle-to-building, V2B).
Why do we need it?
Europe is rapidly expanding its renewable energy capacity. According to a report by Latham & Watkins, in the first half of 2024, renewables generated 61.5% of Germany’s electricity, up from 53.3% the year before, and 7.6GW of new solar capacity was installed in six months. But the grid can’t always keep up. During windy or sunny periods, operators must throttle or shut down wind and solar plants to prevent overloading the grid, wasting clean energy, a problem that cost Germany €3.1 billion in redispatch measures in 2023.
When grids fail to balance, the impact can be severe. For example, in April 2025, the grid frequency in Spain dropped from 50Hz to 49Hz in five seconds, triggering widespread blackouts when more than 70% of the generation came from renewable sources.
Bidirectional charging provides a means to mitigate these fluctuations. Cars sit parked more than 90% of the time, representing a significant untapped storage resource. With the right technology, EVs could store surplus renewable power and release it when demand spikes or the grid falters, stabilising the system without requiring entirely new infrastructure.
Existing technology
The technology is already being deployed, for example, in California, energy recovery from EVs has been incorporated into regional energy plans. In Japan, V2H has been promoted as an emergency power solution, and in China, bidirectional charging has been tested on a large scale with guidelines and government support. The EU Commission classifies bidirectional charging as a key technology for sector coupling.
In Germany, the BDL Next project in Munich brings together automakers like BMW, grid operators, and software companies to test interfaces and business models for wider rollout.
Uwe Möller, a test user, uses a BMW i3 to store solar energy during the day and feed it back into his home at night. Möller said, “Not only do I save money, but I also feel like I’m part of an intelligent system"
Several models already support the technology: the Nissan Leaf (V2H), Ford F-150 Lightning (V2H/V2L), Hyundai Ioniq 5 (V2L), Rivian R1T (V2L), Kia EV6 (V2L), and Tesla is expected to add V2G capability soon.
Why is this not mainstream?
- Cost: Bidirectional wallboxes cost around €4,000, while typical annual savings range from €200 to €800 per vehicle
- Standards: Communication protocols such as ISO 15118-20 exist but are not binding, leaving too much room for interpretation
- Law & Taxation: In Germany, mobile storage devices like EVs are taxed twice, once when charging and again when feeding back to the grid
- Consumer Concerns: Drivers worry about battery degradation or are hesitant to share stored energy
However, a study conducted by Stanford University found that EV batteries often last up to 38% longer in real-world conditions than in laboratory testing, suggesting that bidirectional charging may not accelerate wear as much as previously assumed.
Future potential
As EV adoption accelerates, the potential storage capacity is significant. Global EV sales are projected to reach 22 million by 2025, representing a 25% year-over-year increase, according to IEA's Global EV Outlook.
Even minimal participation can make a significant difference. Research from the BiFLex-Industrie project at the University of Duisburg-Essen suggests that when multiple small storage devices react flexibly, they can compensate for bottlenecks in the grid, minimising the need for fossil fuel reserve power plants.
What needs to happen next
The technology exists, but scaling it requires regulatory clarity and coordinated investment, including:
- Standards so all EVs can connect to all chargers
- Fair taxation so EVs aren’t penalised compared to stationary storage
- Clear billing rules to define who is responsible for what
- Incentives to cut wallbox costs and reward drivers who participate
Bidirectional charging could enable EVs to become grid partners, capturing wasted renewable energy, reducing the need for fossil fuel backup, and ensuring homes remain operational during outages. The technology works, but political will, fair regulation, and consumer trust are needed to turn parked cars into one of the most powerful tools in Europe’s clean energy transition.
