Every year more solar energy is added to the Netherlands. During the day, when the sun shines, we often have a surplus of electricity. But at night, when everyone comes home and the demand for power peaks, the sun is gone. This phenomenon is known as the “duck curve,” a graph that shows the net power demand, with the shape of a duck created by the dip during the day and the steep peak in the evening.
This problem creates major challenges in our energy system. The power grid must scale up from minimal demand to extreme peaks within hours, resulting in grid congestion at more than 250 locations. Grid operators are investing €8 billion annually in grid expansion, but until 2030 the problem will only increase.
The solution? Energy storage. And the largest source of battery capacity we have is already on wheels.
From problem to solution: the electric car as an energy buffer
85% of the global battery market is for electric vehicles. These batteries are much cheaper per kilowatt-hour than individual home batteries due to economies of scale. An average electric car has a battery of 40 to 80 kWh, enough to power an average household for several days.
But electric cars idle on average 95% of the time. That downtime is exactly where the opportunity lies. With two-way charging, an electric car becomes more than a means of transportation. It becomes a mobile energy storage device that not only charges, but also returns energy to the home, building or power grid. Driving and energy management come together in one system.
We Drive Solar is a global pioneer in this technology. The first V2G test was conducted in 2014, a collaboration with Renault followed in 2016, and in 2019 came the world first: the first solar-powered Vehicle-to-Grid charging station with open standard. Meanwhile, We Drive Solar has 10 years of experience and is proving in Utrecht that bi-directional charging works on a large scale.
What is bidirectional charging?
- Vehicle-to-Grid (V2G): delivering energy back to the grid
- Vehicle-to-Home (V2H): using energy in the home or building
- Vehicle-to-Load (V2L): delivering energy directly to devices or installations
The three variants differ in application, but work on the same principle: an electric car’s battery acts as a temporary energy storage device. In effect, the car becomes a driving home battery, with the advantage that you can also drive it.
How does it work technically?
In bi-directional charging, the charging station and the vehicle communicate continuously via smart protocols. They exchange information about charging speed, battery charge and the optimal time to charge or discharge. Based on tariffs, grid capacity and user requirements, the software determines when energy is stored and when it is delivered back.
Important conditions
Not every electric car can charge bidirectionally. Currently, only a few models worldwide are compatible at all, including the Renault 5 and 4 E-Tech, the Hyundai Ioniq 5 and 6, the Nissan Leaf and the Cupra Born. The number of cars that can charge bidirectionally is growing, but compatibility remains limited for now.
The charging infrastructure must also be suitable. A standard AC home charger will not suffice. A bidirectional charging station is needed that can communicate with both the vehicle and the energy grid. In addition, the software must be suitable for energy management: when is charging advantageous, when is feed-in useful?
Specific technical requirements are important for those who want to implement bi-directional charging. The car, charging station and software must be perfectly matched. Safety systems ensure that power only flows back when the grid allows it and stays within the available grid capacity.
What can already be done?
The technology exists, the cars are here, the charging stations have been developed. But as an individual or company, can you get started with two-way charging right now? The short answer: no, not yet. With one important exception.
V2L
This is the only form of two-way charging now widely available. Cars such as the Hyundai Ioniq 5, Kia EV6 and MG4 can power devices via a simple adapter. You may have seen images of a deep fryer connected to an Ioniq 5, or an electric lawnmower getting power from the car. V2L requires no special charging infrastructure – just the car itself and an adapter. Power is limited (usually 3.6 kW), but sufficient for camping, on-site tools or emergency power.
V2G and V2H
These applications – feeding energy back to the grid or to your home – are not yet available to individuals or mainstream businesses. The only place where V2G is now running on a large scale is in Utrecht, within We Drive Solar’s pilot project with MyWheels. There, 500 Renault 5 and 4 E-Tech share cars are equipped with bi-directional charging technology, developed specifically for this purpose. But this is a controlled test environment with professional infrastructure, direct cooperation with grid operators and special arrangements.
The project in Utrecht proves that it can be done technically and makes economic sense, but scaling up to the rest of the Netherlands requires years of development.
Why is implementation so complex?
Collaborations
V2G technology is not new, but large-scale rollout is still pending. This is because there are many parties involved that all need to work together: car manufacturers, charging station manufacturers, grid operators, municipalities, energy suppliers and software developers. Each of these parties has its own systems, standards and interests.
Car manufacturers must equip their vehicles with bi-directional hardware and software. Charging station manufacturers must develop equipment that supports feed-in. Grid operators must make infrastructure suitable and open up their systems. Municipalities must provide space in public spaces. And energy suppliers must offer contracts that make feed-in financially attractive, for example through dynamic tariffs.
Protocols
The ISO 15118 protocol required for communication between vehicle and charging station is still under development, especially the AC version. Regulations are also still lagging behind. It is only from 2030 that European legislation (AFIR) requires new public charging points to be bi-directionally capable.
We Drive Solar is a leader in bringing all these parties together. Through years of experience, close cooperation with Renault and building an open standard, We Drive Solar succeeds where others get bogged down in complexity.
What does bidirectional charging potentially deliver?
For the power grid
Bidirectional charging could significantly increase grid stability. When many electric cars are connected simultaneously, they could absorb peaks by temporarily returning energy. This would reduce grid congestion and make the system more resilient. Instead of further expanding the grid – with all the costs and space requirements that would entail – existing capacity could be used more intelligently.
This would be especially valuable during evening peaks. The moment everyone gets home, starts cooking, turning on the heat and using electrical appliances, demand peaks. At the same time, solar power produces nothing more. Cars charged full with cheap or self-generated solar power during the day could return some of that power in the evening, dampening the peak.
For households
In homes with solar panels, the car could store energy generated during the day and deliver it back to the home at night. This would dramatically increase the proportion of self-use of renewable energy and reduce dependence on the grid. Instead of delivering cheap solar energy back to the grid during the day and buying expensive power in the evening, you could use your own generated energy when you need it.
An electric car with a 50 to 70 kWh battery potentially offers more than enough capacity for the evening peak. Even if the car is not completely full, it could power the household for hours. And when you need to drive the next day, smart software can ensure that the battery is sufficiently recharged in time.
For companies
Companies with fleets of vehicles or office buildings with charging facilities could deploy two-way charging to reduce peak loads. When multiple electric vehicles are connected at the same time, together they could form a significant energy buffer. During times of high demand, such as when air conditioning or manufacturing processes demand a lot of energy, the cars could assist. This would prevent overloading the grid connection and avoid penalties for peak overrun.
Businesses with large solar panel installations could also benefit. Excess solar energy could be stored in the cars and used later, instead of being fed back at low rates or even disconnected during periods of grid congestion.
Utrecht: Europe's first bi-directional region
500 electric share cars as energy buffer
The impact is measurable. Together, these 500 cars can provide 10% of the flexibility needed in the Utrecht region. They can alleviate grid congestion with a capacity of 5 megawatts. That sounds impressive, but it also shows the scale of the challenge: Utrecht has a deficit of 250 megawatts during peaks. So to fully solve the problem, the region would need 50 times as many bi-directional cars.
Yet it is a crucial first step. Utrecht has 35% of its roofs covered with solar panels – one of the highest percentages in the Netherlands. There is a huge surplus of solar energy during the day, and a huge deficit at night. The combination of shared cars and bi-directional charging technology makes it possible to store this energy and use it later, exactly when it is needed.
Why MyWheels?
The partnership with MyWheels is no accident. Share cars are even more often idle than private cars and are also connected to professional charging infrastructure. That makes them ideal for V2G applications. Moreover, MyWheels has a large fleet and the reach to scale up quickly. The partnership allowed We Drive Solar to not only demonstrate the technology, but also prove the business case: bi-directional charging works, delivers value and is financially viable.
And it works: measurable results after five months
After five months of operation with the first 50 cars, grid operator Stedin shared the first concrete results in November. And they are promising.
The cars have reduced 300 kW of grid congestion several times during evening peaks. By smartly charging when plenty of solar and wind energy is available and discharging during peak times, the evening charging peak is avoided. The cars charge with cheap, Dutch solar and wind energy and discharge just when fossil power plants would otherwise have to step in.
In total, the 50 cars delivered more than 65,000 kWh back to the grid in five months. That amounts to an average of 1,300 kWh per car – each vehicle has delivered back an average of 118 hours of energy. With the 170 cars now driving around Utrecht, the goal is to reduce grid congestion by several times 1 megawatt this winter. That power is enough to power 1,000 households during the evening peak.
State of the art: When will two-way charging be available?
V2G
Bidirectional charging is still in its early stages. V2G – delivering energy back to the grid – is currently only applied in controlled pilots such as the Utrecht project. For private households or ordinary businesses, V2G is not currently possible.
That’s because of the enormous complexity of implementation. Car manufacturers, charging station manufacturers, grid operators, municipalities, energy suppliers and software developers all have to work together, and each has its own systems, standards and interests. We Drive Solar is leading the way in getting this collaboration done, but even for us, scaling up to residential customers is a matter of years of development.
V2H
V2H – supplying energy to your own home – seems more readily available in theory because there is no feed-in to the grid, making regulation simpler. Several suppliers are working on systems where the car can power the home during power outages or peak hours. But even V2H is not yet widely available to consumers.
Stable growth
European regulations (AFIR) require new public charging points to be bi-directionally capable from 2030. The Netherlands leads the way in this development thanks to living labs such as Utrecht, open standards and cooperation between governments and companies. Bi-directional charging will grow slowly in the coming years, first in professional applications and pilots, then possibly for private individuals. But large-scale availability for households is still several years in the future.
Common misunderstandings
Any electric car can charge bidirectionally
A standard AC home charger is sufficient
My battery will wear out faster due to extra charge cycles
FAQ
Which cars support two-way charging?
A growing number of models, especially newer EVs with ISO 15118 support. Examples include the Renault 5 and 4 E-Tech, Hyundai Ioniq 5 and 6, Nissan Leaf, Cupra Born and Volvo EX90. For a current overview, see the list of cars capable of bi-directional charging (2025).
Important to know: at the moment, there is no car yet that has V2H or V2G working ‘out of the box’. These cars do have the technical ability and potential to charge bi-directionally, but only in specific test setups – such as our project in Utrecht – does V2G actually work. V2L (delivering energy to devices) is already possible in many of these models.
Can I use my car as a home battery?
At the moment, not yet for individuals. But potentially in the future, V2H technology could use an electric car as energy storage for the home or office. The technology is being developed and is expected to be available sooner than V2G because there is no feed-in to the grid, making regulations simpler. More information on how a car works as a home battery is available.
Does two-way charging with solar panels work?
Yes, this is precisely one of the main advantages. Solar energy can be stored in the car during the day and used later. The combination of two-way charging and solar panels maximizes self-consumption and minimizes dependence on the grid.
Will my car stay full enough for my daily drives?
When two-way charging is available, smart software will ensure that there is always enough energy left in the battery for planned trips. Users can then set the minimum amount of range they need. The rest of the capacity becomes available for energy services. This is how the system is designed to work – the car remains primarily a means of transportation.
What does a two-way charging station cost?
When bi-directional charging stations become widely available, it will again vary by provider and type of installation. Bidirectional charging stations are more expensive than standard chargers, but prices fall as the technology scales. Subsidies and financial benefits from feed-in can pay back the investment.
However, there is currently no bi-directional charging station that works “out of the box” for residential customers. Many providers do offer V2G-ready charging stations, but they cannot actually charge bidirectionally yet.
Do I make money by feeding energy back from my car?
For individuals, this is not currently possible, but in the future it could be. With dynamic energy tariffs, you could then take advantage of price differences: charging when power is cheap and feeding it back during expensive hours. There could also be programs where grid operators pay for flexibility.
The only project where this is already proven to work is our project in Utrecht. There it does make money by feeding energy back at times when it is expensive.