The car as a battery: the silent revolution has begun
Maarten Steinbuch: “Stationary cars can serve as relatively inexpensive home batteries that reduce the load on the electricity grid.”
Published on August 16, 2025
© We Drive Solar / Renault
Maarten Steinbuch is a high-tech systems scientist, entrepreneur and communicator. He holds the chair of Systems & Control at Eindhoven University of Technology, where he is Distinguished University Professor. His research spans from automotive engineering to mechatronics, motion control, and fusion plasma control.
What was once merely a means of transportation is becoming an indispensable link in the energy system of the future, writes Professor Maarten Steinbuch. The car is a mobile energy storage for the entire neighborhood.
Imagine coming home in the evening, connecting your car to the charging station, and having it feed electricity back into your home. It only starts charging later, when electricity is much cheaper or even free. It's already happening in Utrecht. There, electric shared cars serve not only as a means of transportation but also as mobile energy storage for the entire neighborhood. They charge during the day using solar power and feed it back to the neighborhood in the evening. The car as a battery. No longer a dream for the future, but a reality today.
Pioneer Robin Berg started years ago with specially equipped Renault ZOEs and smart charging stations that can feed power back into the grid. Now The Sharing Group – known for MyWheels and energy supplier ZeroEnergie – is taking the next step. They are buying the new electric Renault 5 on a large scale, which supports Vehicle-to-Grid (V2G) as standard, enabling energy to be fed back into the grid. Each car has a 40-kilowatt-hour battery, four times as much as a home battery. By 2026, 500 of these cars will be on the road in Utrecht, together accounting for 20 megawatt-hours of storage capacity. And that's just the beginning.
Feed-back
This comes at just the right time. Because in 2027, the net metering scheme will end. Solar power fed back into the grid will no longer be offset against consumption. As a result, on sunny days, you will have to pay to supply electricity. The trial set up by MyWheels in Utrecht with shared cars will therefore be increasingly adopted by private individuals.
Many people switch off their solar panels as soon as the grid is full. But what if you could store that electricity locally—in your own car or a shared car in your street? Then energy sharing would become a revenue model, especially with a dynamic energy contract. This is still rarely used, but it will soon become the norm once net metering disappears. With smart devices and local storage, our homes and neighborhoods are being prepared for a sustainable and affordable future.
What is happening here is nothing short of revolutionary—and it is by no means a coincidence. Three major trends are converging at exactly the right moment and reinforcing each other in a way that is accelerating the energy transition.
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Flexible charging
Mobility and energy are rapidly converging. Electric driving is no longer a niche market: thanks to large-scale production of solar and wind energy, sustainable electricity is becoming increasingly affordable. Cars, buses, and trucks are driving en masse on batteries. The charging infrastructure is in place, and charging speed is no longer an obstacle. Charging can be flexible – at night or at work, when electricity is cheapest. And because vehicles can feed energy back into the grid, they are no longer a burden on the grid, but rather a buffer.
At the same time, batteries are becoming better, smarter, and more sustainable. Whereas older batteries last for around 1,500 charging cycles, the new LFP variants can already handle 5,000—good for millions of kilometers. And the solid-state battery, currently still in development, promises as many as 10,000 cycles. Fears of rapid wear and tear during intensive use are outdated. This makes dual use possible: driving and storing energy.
Finally, decentralization is the key to a robust energy system. Electricity demand will triple in the next ten years, partly due to the electrification of transport and industry. Upgrading the national grid will take time, but decentralized systems can already help. Think of business parks, airports, or residential areas with their own generation and storage - so-called “holons” - that respond intelligently to supply and demand. The Utrecht neighborhood, which uses shared cars as batteries, demonstrates that it is possible.
Can we apply this on a large scale? Most existing charging stations will have to be replaced or modified, because only bi-directional charging stations can feed electricity back into the grid. Fortunately, more and more manufacturers are offering this, and it is slowly becoming the norm. Are you a private individual or company looking to install new charging points? Then pay close attention.
Earning
Virtually all charging solutions in the Netherlands are smart and connected, and are becoming increasingly intelligent through software updates. However, the hardware must support feed-in. Not all cars can do this yet, although the number of models is growing rapidly. The opportunity to earn money from your battery will also become a strong selling point.
In addition, only 40% of households have their own driveway. That is why solutions such as those in Utrecht – where shared cars in the neighborhood function as batteries – are so interesting. Opportunities are also emerging in business parks and at employers: they can use their parking spaces to use employees' batteries for their own energy management, for example, in exchange for payment or free parking.
In short, the future has already begun: stationary cars can serve as relatively inexpensive home batteries that relieve the strain on the electricity grid. They charge with cheap or even free electricity that would otherwise be lost, and that energy can also be used by others. This means that owning a car may soon be cheaper and more environmentally friendly than not having one. Who would have thought?
This column was originally published in the FD and is used with permission.