Using electric vehicles to store energy and feed back into the grid could soon save Europe’s energy companies and motorists billions of euros a year, a new study finds. EVs equipped with bidirectional charging can act as ‘batteries on wheels’ that draw down electricity at times of oversupply and give back when demand is higher. But their potential may not be realised without common EU standards to ensure interoperability between all EVs and chargers.
The so-called vehicle-to-grid (V2G) technology can save the EU’s energy systems €22 billion annually by 2040, according to the report by research institutes Fraunhofer ISI and ISE for Transport & Environment (T&E). That would be a 8% reduction on the cost of building and running the EU energy system. This could result in a saving of more than €100 billion between 2030 and 2040, it finds.
Integrating renewables
The massive potential cost reductions are due to EVs helping to accommodate the transition to renewable electricity in grids. EVs plugged in at home or work can reduce the need for stationary battery storage – to store energy when there is an excess supply of wind or solar power – by up to 92% in 2040. With V2G, Europe’s grid could integrate up to 40% more solar PV capacity.
By storing excess renewable energy that would otherwise be lost, Europe’s EV fleet could contribute up to 9% of the EU’s annual power needs by 2040. This would make EVs the fourth largest electricity ‘supplier’ in the EU and reduce the need for additional generation capacity.
Fabian Sperka, vehicles policy manager at T&E, said: “Electric vehicles have put road transport on the path to decarbonisation, but they have more economic benefits yet to be realised. Bidirectional charging will offer batteries on wheels for free, reducing the need to build energy storage for excess wind and solar power.”
Electricity bill and battery life
By allowing EVs to draw down excess electricity when it’s cheap, or from home solar panels, bidirectional charging could save EV drivers up to 52% on annual electricity bills, according to the study. This would equate to reductions of up to €780 a year, depending on factors such as location, whether their house has solar panels, and their vehicle’s battery size. Bidirectional homechargers are expected to be around €100 more expensive than conventional wallboxes.
Bidirectional charging can also extend the life of EV batteries – contrary to commonly held concerns about cell degradation due to regular charging and deloading. Battery lifetimes could be extended by up to 9% compared to standard EV charging practices, the report finds, as the car is maintained in an optimal state of charge.
Challenges
Europe can reap the benefits of V2G technology almost for free as the additional costs of bidirectional onboard chargers and wall-boxes would be offset by reduced electricity bills within a few months. However, as different car manufacturers are currently focusing on either AC or DC bidirectional systems, the lack of interoperability is holding back the adoption of V2G.
Fabian Sperka said: “V2G can only take off if we ensure all EVs can work with all chargers. Lawmakers can unlock the potential of this technology by deciding the EU standards for bidirectional charging. That will be a win for consumers, the environment and progress towards the EU’s climate and energy goals.”
