Batteries in Europe’s electric cars have 10 times the capacity of grid-connected energy storage

The batteries installed in Europe’s electric vehicles have ten times the capacity of stationary energy storage systems connected to the grid. This is according to a new report by the think tank Bruegel, which highlights the untapped potential of vehicle-to-grid technology.

60 GWh on the grid, 600 GWh on wheels

According to Bruegel’s “European Clean Tech Atlas”, stationary energy storage capacity in Europe reached around 60 GWh in 2024, encompassing residential, commercial, industrial and utility-scale installations. As the think tank points out, this capacity would be enough to supply or absorb the average power of Europe’s electricity grid for only about 15 minutes.

By comparison, Bruegel estimates that Europe’s electric vehicle fleet already contains around 600 GWh of battery capacity. This estimate was based on an extrapolation of data from the International Energy Agency’s “Global EV Outlook”.

As the report notes, this mobile capacity—if fully connected to the grid—could theoretically supply Europe’s electricity grid with continuous power for almost two hours.

What is V2G, and why has it yet to be widely adopted?

Vehicle-to-grid technology enables an electric car’s battery to act as both an energy consumer and an energy source, feeding electricity back into the grid when it is needed most.

In theory, this means that hundreds of thousands of parked electric cars could serve as a vast, distributed energy storage system, without the need to build costly new stationary installations.

However, the authors of the Bruegel report caution that the estimate of almost two hours of power for the entire European grid remains purely theoretical for now. Making it a reality would require two elements that are still under development:

• V2G technology—the hardware and standards that enable electricity to flow in both directions between a car and the grid—is not yet widely available or standardised at scale.
• Smart integration—management systems that would allow grid operators to effectively and safely control thousands of distributed car batteries simultaneously.

Without these two elements, the enormous capacity contained in electric car batteries remains unavailable to the power system. The resource physically exists, but the technical and organisational connections needed to put it to use are not yet in place.

A growing market for home energy storage

Sales of home energy storage systems in Europe surged in 2023 as energy prices rose and have remained high ever since, according to the Bruegel report.

Residential systems account for just over half of the grid-connected energy storage market. Meanwhile, utility-scale grid-connected battery storage is also growing year by year, with individual projects increasingly reaching capacities of hundreds of megawatt-hours.

V2G as the missing link in the energy transition

SolarPower Europe is calling for a tenfold increase in Europe’s stationary energy storage fleet by 2030, with a capacity target of 500–780 GWh. This scale of storage would support a power system running entirely on renewable energy.

Even this target represents less capacity than Europe’s electric vehicle fleet already holds today. The future of energy storage in Europe may therefore depend on more than the pace at which new stationary batteries are installed. The speed at which V2G technology develops will be equally important. It will unlock a resource that is already parked in driveways across Europe.