Agora Bidi – Making the potentials of bidirectional charging visible

In this project, scientists from the Reiner Lemoine Institute are investigating how bidirectional charging of electric vehicles (BiDi) can help reduce one’s own electricity costs and stabilize the energy system on behalf of the thinktank Agora Verkehrswende. Based on the results, the project team develops recommendations for action for politics and science.

Prepare usage potentials in an understandable way

Bidirectional charging means that electric vehicles can not only absorb electricity from the grid or from their own photovoltaic system on the roof, but also release it again – for example into the power grid or into one’s own home. The project team is investigating the energy industry benefits of this approach for different customer groups. To this end, the scientists review existing studies and conduct interviews with practical experts, for example from the energy industry or law.

Impact on vehicle costs

The team is investigating the extent to which bidirectional charging reduces the total cost of ownership (TCO), i.e. the total costs incurred over the service life of an electric vehicle. To this end, the experts create typical user profiles and analyze how much money can be saved with BiDi applications – for example, through self-consumption optimization or participation in the electricity market.

Recommendations for better framework conditions

Based on the results, the team develops concrete proposals on how legal and regulatory hurdles can be removed in order to bring BiDi applications into practice. The recommendations are aimed specifically at decision-makers in politics and authorities. A central goal of the project is to present the complex interrelationships in an understandable way – even for people without previous experience in the energy industry. The results are prepared in such a way that they provide an easy introduction to the topic and provide practical application examples.

Project period: July – September 2025

• Analysis of energy-related uses of bidirectional charging
• Interviews with relevant stakeholders
• Development and evaluation of exemplary customer profiles
• Quantification of TCO effects by BiDi applications
• Derivation of concrete recommendations for action for politics, science and journalism
• Target group-oriented and understandable preparation of the results

Read the complete report (only in German) here.

Key results:

1. As flexible storage systems, the batteries of electric vehicles can reduce the costs of the energy transition.
   With the expansion of renewable energies, flexibility in the electricity system is becoming increasingly important. Bidirectional charging can make an important contribution to balancing the fluctuating feed-in from wind and solar energy and ensuring grid stability. The integration of electric vehicles as flexible storage systems contributes to a cost-efficient energy transition.
2. Bidirectional charging can reduce the overall cost of electric vehicles.
   With bidirectional charging, electricity can also flow from the car back into the house or into the power grid. If, for example, the price of electricity is high, the cheaper purchased electricity can be used in the house or sold on the electricity market. This reduces the electricity costs for the annual mileage of electric vehicles.
3. Feed-back into the power grid (vehicle-to-grid) offers a high profit potential.
   Arbitrage profits of up to 500 euros per year can be realized through trading on the electricity market. Alternatively, the provision of balancing energy offers similar profit potential. However, profits depend in particular on price fluctuations on the electricity market.
4. In combination with self-sufficiency (vehicle-to-home/building), additional savings are possible.
   If the electric vehicle is also used for the self-supply of a private household or commercial building when using a PV system, this increases profits. Vehicle-to-home applications alone, on the other hand, bring hardly any financial advantages compared to controlled charging, as the additional costs for bidirectional charging infrastructure often exceed the profits.
5. In order to fully exploit the potential of bidirectional charging, a reform of the political framework is needed.
   If feeding back into the power grid is financially worthwhile, bidirectional charging will be widely used. Flexible Connection Agreements (FCAs) can be effective in this regard. With them, grid operators can ensure that charging and unloading is carried out in a grid-compatible manner. In return, they can reduce grid fees for temporarily stored electricity, which would reduce individual electricity costs. The technical prerequisite for this is the rapid expansion of intelligent metering systems so that, among other things, sufficient information on grid utilization is available.