Discover how V2G (Vehicle-to-Grid) can transform your electric car into a mobile energy store and a potential source of income. Learn about the technology, benefits and prospects.
V2G is the technology that turns your electric car from a means of transport into a mobile energy storage. Genome bidirectional charging the car can not only receive electricity, but also send it back to the mains or home when the need is greatest.
Did you know that your electric car can become more than just a means of transportation? With v2g, or Vehicle-to-Grid, your electric car can actually act as a mobile energy storage facility that not only receives electricity but also sends energy back to the grid when needed. This is an exciting development that is changing the way we look at electric cars.
V2G stands for “Vehicle-to-Grid” and refers to technology that allows electric cars to return stored energy to the grid. Bi-directional charging thus enables an active role for electric car owners in the energy system, while at the same time it can lower costs and increase the use of renewable electricity. This becomes especially interesting when we compare the capacity of v2g cars with ordinary home batteries - while a home battery for storing solar energy most often holds only 5—10 kWh, An electric car battery can store up to approximately 100 kWh. V2G transport thus becomes not only a means of getting from point A to point B, but also a potential source of income. There is also the possibility of using v2g chargers to connect the car with the house's electrical system, known as V2H (Vehicle to Home), which in the not too distant future could become an alternative to the home battery.
In this article, we go over everything you need to know about V2G — from basic technology to practical applications and how it can become a future source of income for you as an electric car owner.
V2G technology is changing the way we look at electric cars and their role in the energy system. While I previously introduced the basic concept, we are now going to delve into what this technology actually means and why it is so significant for the energy supply of the future.
V2G, or Vehicle-to-grid, is a technology that allows energy to be sent from an electric vehicle back to the grid. This means that a vehicle battery becomes an energy storage device that can be plugged into the grid to do a kind of reverse refueling. Simply put, it comes down to the fact that the car not only receives electricity, but is also able to supply electricity back when parked and connected to a special charger.
For this to work, a bidirectional charger is required that can handle current in both directions. Technically, this is done through a communication between the car and the charging station via the protocol ISO 15118, which ensures safe and intelligent charging. This standard is central to enabling the advanced communications required for V2G functionality.
Unlike traditional charging, where the current only goes in one direction (from the grid to the car), V2G allows for a two-way flow of energy. The process can be broken down into three distinct stages:
It is important to note the difference between the concepts of “bidirectional charging” and “V2G”. While bi-directional charging refers to charging being able to take place back and forth between vehicles and power grids, V2G technology specifically enables the flow of energy from the car's battery back to the grid. In addition, V2G differs from other technologies such as V2H (Vehicle-to-Home) in which the energy is used directly in the home instead of being returned to the general grid.
V2G technology plays a crucial role in the energy systems of the future for several reasons. First of all, it helps to stabilize the power grid. When there is an imbalance between production and consumption, variations in frequency occur, and then stabilizing resources such as batteries are required. By having many different resources for frequency regulation, we get a more reliable power grid.
V2G also provides important economic benefits. A 2015 study found that vehicle owners could get significant payments by charging their electric cars during off-peak times when the grid is cheaper, storing the energy in the car battery, and selling it back to the grid during peak times when electricity prices are higher.
In fact, electric car batteries are the most cost-effective form of energy storage, as they do not require any additional investment in hardware. With V2G, the battery capacity can be used up to 10 times more efficiently than with conventional smart charging.
By 2030, there could be as many as 250 million electric cars globally, meaning we will have roughly 250 million small energy stores on wheels. To put this in perspective: if just 10,000 electric cars in Gothenburg could share 10-20% of their battery, it would provide 100 MW of extra capacity, equivalent to almost 12% of the grid's power.
V2G is also central to the transition to renewable energy. As the energy system increasingly relies on renewable energy sources with a less predictable electricity generation, flexible energy solutions such as V2G are becoming increasingly important. Research shows that by the end of this decade, electric car batteries should be able to meet demand for short-term energy storage.
Finally, V2G provides an important societal benefit in the form of increased resilience. If there is a crisis where the electricity supply suffers, vehicles with charged batteries can deliver electricity exactly where it is needed at the moment. This makes V2G a technology that not only promotes climate change but also strengthens our ability to deal with crises and disruptions in energy supply.
Now that we know what v2g is, let's delve into how the technology actually works in practice. The V2G process consists of several steps that together enable a bi-directional flow of energy between the electric car and the grid.
The first step in the v2g process is simply to charge the car. This takes place just like regular charging, but with one important difference - the system takes into account the power grid data, the current battery level of the car and your desired charge level to create a personalized recharge plan. With v2g, charging becomes more intelligent, because the communication between car and charger is more advanced.
The charge should ideally occur when electricity consumption is lower and prices are more favorable, for example at night. For v2g charging, it is especially important that the car is connected to the charger for extended periods of time, making home charging or charging in the workplace ideal. This gives the system the flexibility to control both charge and discharge at optimal times.
When the car is charged, the battery acts as an energy store. Modern electric car batteries can store significant amounts of energy -- up to 100 kWh in some models, which is significantly more than home batteries that usually hold only 5-10 kWh.
The battery holds the energy until it is needed, either for driving or to return to the mains. With smart steering, the system always ensures that the car has enough energy left when the driver needs it. When using v2g solutions, the car battery is usually charged to 70-90% when the driver needs to go away. This is the basic requirement for all v2g technology — the driver must be able to specify when the car is needed and how much energy should be available at that time.
When electricity is needed in the system, the real magic of v2g technology happens — the discharge. A v2g charger takes electricity from the car battery and sends it back to the mains, where it continues to the nearest place where it is needed. This can occur based on various signals, for example, when there is an excess of energy or high energy consumption nearby.
The discharge can also be done to balance the load in the power grid, for example by taking power when there is an excess and returning it for replacement when the grid is heavily loaded. With v2g, the balancing of the power grid can continue for the entire time the vehicle is plugged in, unlike conventional smart charging where the ability to balance ceases when the battery is fully charged.
The key to making v2g work is the communication between car and charger. This is done via the ISO 15118 standard, which is designed to support the transfer of electricity between electric vehicles and charging equipment. This standard defines communication messages and sequence requirements for bidirectional power transmission.
ISO 15118 allows the electric car to tell the charger how much energy it currently has, how much it needs and when it needs it. This allows for more efficient charging, which is especially useful if you are using solar panels or charging during low-load periods.
In addition, the standard provides several use cases such as secure communication, smart charging and the “Plug & Charge” function. Plug & Charge allows an electric vehicle to automatically identify and authorize itself to a compatible charging station on behalf of the driver to obtain energy to charge its battery. The only thing required of the driver is to plug the charging cable into the electric car and/or charging station.
V2G chargers play a crucial role in the process because they enable the bi-directional current. These are usually DC (DC) chargers, as this allows one to bypass the car's own one-way on-board chargers. This is necessary because additional power electronics are needed to convert the car's direct current into alternating current that is present in the electrical grids.
In the v2g process, the inverter plays an important role — it converts between electric vehicle battery (DC, DC) and mains power (AC, AC). There are mainly two types of inverters: either placed in the charging box or built into the car.
V2G chargers are already available in various shapes and sizes, usually with a maximum charging power of around 11 kW — enough for home or workplace charging. However, there are also v2g chargers with charging power up to 15 kW. However, a v2g charging box is about twice as expensive as a charging box without this technology, but in return enables smart solutions such as automatic identification when paying.
The market for V2G-compatible electric cars is growing rapidly in Sweden, although the technology is still under development. In order to use V2G, both your car and charging equipment need the right conditions. Let's take a closer look at which cars are already ready for the energy systems of the future.
The Volkswagen Group has taken the lead in the development of V2G in Sweden. All cars built on their MEB Platform and manufactured since spring 2023 are prepared for bidirectional charging. This includes:
In addition, there are several other car models that already support or are being prepared for V2G technology:
Currently has about 20,000 rechargeable passenger cars In Sweden already technology for V2G. However, there are still not enough charging stations with V2G support for the technology to be universally applicable.
For an electric car to work with V2G, specific technical conditions are required. First of all, the car must be equipped with a bidirectional on-board charger. Most electric cars today do not yet support this feature, but development is moving fast.
As for the software, the cars need the right software version to handle bi-directional charging. Volkswagen vehicles, for example, require ID. Software 3.5 or higher to be compatible with V2X technology. At the same time, ISO 15118 hardware and software are needed to enable the advanced communications required for V2G.
The type of contact also matters. Many vehicles with CHADEMO connectors already have V2G capability, while cars with CCS connections have had limitations in the past.
A crucial question for many car owners is how V2G use can affect the car's warranty and battery life. When some of the charging cycles are used for other than powering the car, it can potentially affect carmakers' warranty commitments for the capacity of the batteries over time.
Some automakers have expressed concern that the V2G application would affect battery life and function. This has led some manufacturers to limit the function to a certain amount of expended energy or time. The key question, then, becomes whether car manufacturers are willing to give up battery capacity for purposes other than driving.
Research results show mixed conclusions. There are studies that indicate that V2G can accelerate the cyclic aging of the battery, but at the same time it is unclear whether V2G affects battery degradation more than other charging. Important to note is that the demotion is usually very small and that the utilization of V2G is based on revenue covering any costs.
To protect the battery, many V2G systems limit how much energy can be drained from the battery. From what we have seen, the batteries usually cannot go below 20% charge, and the user can set a higher limit himself if desired.
Therefore, before investing in V2G technology, it is important to check what applies to your particular car, whether bi-directional charging is approved and how this may affect the warranty.
In order to actually take advantage of the potential of v2g technology in your home, some specific components and customizations are needed. Understanding these prerequisites is crucial before investing in the technology, as it requires more than just an electric car with the right features.
The most important component to making v2g work at home is, of course, a bi-directional charging box. These chargers are different from standard charging boxes because they can handle power in both directions — both to and from your electric car. A bi-directional charging box must have:
In 2023, Wallbox launched its Quasar 2, a DC charger for home use that can work with v2g without the car having to have a bi-directional on-board charger. This opens up the possibilities of v2g for many electric car owners, as one no longer has to wait for the v2g support of car manufacturers.
However, the installation of a v2g charger is more complex and costly than that of a standard charging box. In addition, additional power electronics are needed to convert the car's direct current into alternating current used in the electrical grid, contributing to higher costs and a more advanced installation.
In order to sell electricity from your electric car back to the grid, you need to have the right type of electricity meter. It must be able to measure current in both directions — i.e. both purchased and sold electricity. Unfortunately, only about 50% of all electricity meters in Sweden currently have this function, which means that an electricity meter replacement may be necessary.
The home's electrical system must also be able to handle electricity flowing from the car back to the house. This may mean the need for:
It is important to note that installation must be carried out by a competent electrician and sometimes notified or approved by the power grid owner. Since v2g is still relatively new, some grid companies lack bidirectional energy management procedures, which can affect installation and operation.
If you plan to install v2g charging in the future but are not ready right now, there are steps you can take to future-proof your electrical installation.
Furthermore, the electricity companies in Sweden need to adapt the electricity grid in a way that allows them to take advantage of the energy that Sweden's entire fleet of electric cars has in their car batteries. This is a development that is ongoing but will take time to fully implement.
Another important aspect is that the peak power of what an electric car battery coupled to a hefty charging box can handle is many times what a normal stationary battery can handle. However, you will be disappointed if you think that it is possible to extract 300 kW from your home plant via the car, since the low-voltage network is not built for this.
Thus, to summarize, you need:
With these conditions in place, your electric car can begin to act as a mobile energy storage that contributes both to your home and to a more stable electricity grid.
Sweden is at the forefront of the development of v2g technology but when will this innovation become widely available to Swedish electric car owners? Let's look at where we stand today and what the road ahead looks like.
Several exciting pilot projects are underway in Sweden to test and evaluate v2g technology. One of the most high-profile is the one that takes place in the housing association Stenberg outside Hudiksvall. There, Volkswagen has established its largest pilot project with eight ID.4 cars that both charge and supply electricity back to the properties and the grid.
This project has recently been expanded. Vattenfall, Energy Bank and Scania Volkswagen Dealers (SVÅ) have launched a major pilot project with 200 bi-directional chargers from Ambibox to be installed at retailers and individuals in southern and central Sweden.
In addition, Göteborg Energi operates together with Volvo Cars and Polestar project to test the capabilities of v2g technology. In March 2023, four Volvo cars with bi-directional charging equivalent to 111 kWh delivered to Göteborg Energi's local flexibility market.
Despite the fact that the technology already exists, there are several factors that slow down development. In particular, there are no clear regulations and standards for how v2g should be handled. One problem is that the regulation is not written with v2g in mind — for example, as a private individual under the current regulations, you can only have solar cells as electricity generation, not an electric car.
Furthermore, the process is complicated by the involvement of many actors — from car manufacturers and charging box manufacturers to grid owners and end customers. ISO standards for communications are not yet fully in place, delaying the development of compatible products. In addition, there are unanswered questions about business models, policies and agreements for v2g usage.
Some technical challenges also remain. For example, the low voltage grid is not built to handle the high power that v2g systems can theoretically deliver.
Several industry assessors believe v2g will become standard in better cars within five years. Even now is about 20,000 rechargeable passenger cars in Sweden equipped with technology for v2g, but more vehicles and chargers are needed for large-scale use.
After evaluating the ongoing pilot projects, such as the Vattenfall/Volkswagen collaboration, the target is a commercial launch. According to some assessments, the first v2g connections could become a reality as early as this year, but initially only for a few users.
Thus, development is moving forward, but for v2g to really break through, it requires easier use, clear business models and standardization — something that industry players agree on.
V2G technology offers several economic benefits that make the investment worth considering for electric car owners. Let's explore how this innovation can impact your everyday life and wallet.
With v2g, your electric car can act as an energy store for your home. By using energy from your car's battery when electricity prices are high, you can significantly lower your overall energy costs. Calculations show that Swedes who switch from an internal combustion engine to an electric car can save up to SEK 2,800 per year, but with v2g technology, the savings can increase to almost 10 000 SEK annually.
According to reports from Denmark, electric car owners already earn more than $1,500 a year, equivalent to around one thousandth of a month, by “lending out” their battery capacity. This leased battery capacity helps stabilize the power grid, and profits are shared between the service provider and the electric car owner. Above all, it involves selling surplus energy back to the grid or taking advantage of dynamic pricing schemes.
V2G enables electric cars to send electricity to the local grid for an hour without affecting the car's everyday use. Electric cars that are plugged in can support the network during the few hours per year when the load is at its highest. In addition, v2g can help stabilize the grid by providing additional energy resources during periods of grid instability.
For homeowners with solar cells and electric cars, v2g technology can be particularly beneficial. You can use the car as an energy store for the home, which is often more economical than selling the self-produced electricity and then buying it back. This ensures that renewable energy is not wasted but always has a place to be stored.
V2G technology It is on the threshold of a breakthrough in Sweden. In fact, this innovation represents a paradigm shift in how we view our electric cars — from simple means of transportation to active parts of our energy system. Thus, we now have the opportunity not only to use electric cars to get from point A to point B, but also as mobile energy stores that contribute to a more stable and flexible electricity grid.
The benefits of V2G are undeniably many. The ability to lower electricity costs, generate extra income and support the grid during peak times makes the technology attractive to electric car owners. In addition, V2G contributes to a more sustainable use of energy, especially for homeowners with solar cells that can maximize the benefit of their self-generated electricity.
Despite these benefits, there are still challenges to overcome. The lack of clear regulatory frameworks, technical standards and limited availability of compatible cars and chargers are slowing progress. However, the ongoing pilot projects in Sweden are showing promising results, indicating that the technology may soon become available to the general public.
The future of V2G in Sweden looks bright. As more cars are prepared for bi-directional charging and infrastructure is developed, the technology will become more accessible. Over the next five years, V2G is expected to become standard in premium cars, and subsequently spread to more vehicle models.
If you are thinking of buying an electric car, you should therefore consider whether V2G compatibility is important to you. Alternatively, if you already own an electric car, investigate whether it supports or can be upgraded to V2G technology. While all the prerequisites are not yet in place, it is wise to prepare for this exciting development that could transform your electric car from an expense into a potential source of income.
Q1. What is V2G and how does it work? V2G stands for Vehicle-to-Grid and is a technology that allows electric cars to return stored energy to the grid. Through a bi-directional charger, the electric car can both receive electricity and send back excess energy when parked, which helps stabilize the power grid and can bring economic benefits to the car owner.
Q2. Which electric cars support V2G technology? Several car models support or are being prepared for V2G technology, including Volkswagen ID models, Audi Q4 e-tron, Škoda Enyaq, Volvo EX40 and EX90, Polestar 2 and Kia EV6. The number of compatible models is constantly increasing as technology advances.
Q3. What does it take to use V2G at home? To use V2G at home, you'll need a V2G-compatible electric car, a bi-directional charging box, an electricity meter that can measure current in both directions, and properly sized cables and fuses. In addition, an agreement with an electricity dealer capable of handling bidirectional energy transfer is required.
Q4. How can V2G affect my finances as an electric car owner? V2G can reduce your electricity costs by using your car's battery as an energy store when electricity prices are high. You can also get extra income by “lending” your battery capacity to the grid. Savings of up to SEK 10,000 per year have been reported for electric car owners using V2G technology.
Q5. When will V2G become widely available in Sweden? Several pilot projects are underway in Sweden, and the industry expects that V2G could become standard in premium cars within five years. Broader commercialization could occur within 1-5 years, provided technical and legal challenges are resolved. The first commercial V2G connections could become a reality as early as this year for a limited number of users.
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