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V2G – Vehicle-to-Grid: All you need to know

Summary

V2G stands for “Vehicle-to-Grid“. It is a ‘smart’ technology that makes it possible to return energy from the batteries of electric vehicles back into the energy system. V2G technology can fulfil a similar function to battery storage power plants and solar batteries.

Cars, and thus electric cars, are parked on average 96% of the time, or more than 23 hours a day, and for daily journeys usually only about 1/10 of the battery capacity of an e-car is needed.
By 2030, there will be 140 to 240 million electric vehicles worldwide. This in turn means that there will be at least 140 million tiny energy storage devices on wheels with a total storage capacity of 7 TWh. (BTW: per capita consumption in Germany per year  ~7,2 MWh; 1 TW = 1.000.000 MW = 1.000.000.000.000 W)

V2G contributes to mitigating climate change by enabling our energy system to balance ever-increasing amounts of renewable energy for use.

To successfully tackle the climate crisis, three things need to happen in the energy and mobility sectors:
Decarbonisation
increasing energy efficiency
electrification of mobility.

Asian manufacturers are pioneers, especially Hyundai, but VW and Polestar also have models with bidirectional charging.

Summary of benefits that best fit your particular goals:
– Reduction of total cost of ownership for fleet solutions
– Car manufacturers can offer vehicles with added value
– Energy market players can act better and optimise the balance in the grid
– Grid operators can optimise investments and stabilise the grid

V2G is still a project-based business model, but this could change and evolve into an interesting commercial business case.

In order to advance V2G technology, further business models need to be developed, commercial feasibility studies need to be conducted and regulatory issues need to be examined.
Also the impact of V2G on the life cycle of EV batteries does not seem to be harmful, but needs to be further investigated.

Details

1. What is V2G and V2X?

Vehicle-to-grid approaches are based on the fact that most vehicles are parked for most of the day. For example, most private vehicles in Germany are moved for less than 2 hours a day and are thus available for V2G applications for most of the day. Using V2G, electric vehicles can be charged or discharged based on grid demands. For example, total energy production and actual consumption in the surrounding area can be taken into account. Since the charging time is usually much shorter than the actual standing time, battery charging times can be adapted to the respective demands in the power grid and electric cars can thus be used for load management.
For orientation:
Assuming that 70 % of the vehicles have a battery size of 20 kWh and the battery is 50 % charged, one million electric cars could provide 7 GWh of additional storage capacity.
Or in other words: a single electric car can store enough electricity to supply up to five households for 24 hours. An entire fleet can store surplus electricity from renewable energy sources over the course of the day and balance the peak demand of an entire city in the morning and evening. Thanks to V2G technology, the vehicles of the future can not only deliver electricity to the grid, but also to customers’ homes.

V2X means Vehicle-to-Everything. This includes many different application examples such as Vehicle-to-Home (V2H), Vehicle-to-Building (V2B) or even Vehicle-to-Grid.
In summary, the basic idea of vehicle-to-grid is the same as for normal smart charging. Smart charging allows the charging of electric cars to be controlled in such a way that the charging power can be increased and decreased as needed. V2G goes one step further and allows the charged electricity to be temporarily fed back into the grid from car batteries to compensate for fluctuations in energy production and consumption.

2. Why is V2G also interesting for erveryone?

In the context of energy production, decarbonisation refers to the use of renewable energy sources such as solar and wind power. As the use of renewable energy increases, so does the demand for storage options for the green-generated energy. (Btw: Fossil fuels can also be seen as a form of energy storage, as they are stored and only release energy when burned.) However, the principle works differently for wind and solar energy. The energy should either be used right where it is produced or it must be stored to be used later. Therefore, the increase in renewable energy inevitably makes our energy system more volatile and requires new ways to balance and store energy. And this is where electric vehicles (EVs) come in, as their batteries are perfect for storing energy.
At the same time, the traffic sector will make a major contribution to CO2 reduction (increasing number of electric vehicles). Since they are available, electric vehicle batteries are by far the most cost-effective form of energy storage, as they do not require any additional investments or further hardware.
With V2G, battery capacity from EVs can be used more efficiently, the electric vehicle charging is switched from demand response to a battery solution. This enables ten times more efficient use of the battery compared to one-way smart charging.

3. How does Vehicle-to-Grid work?

When it comes to making V2G practical, one particular point is most important: EV drivers must have enough energy in their car batteries when needed. When end-users drive to work in the morning, the car battery obviously needs to be full enough to get there and back. This is basically the main requirement for V2G: the EV driver must be allowed to decide when he wants to unplug his car and how full the battery should be at that time.
When using smart charging, the possibility of balancing the grid ends exactly when the battery is fully charged. With V2G, on the other hand, grid balancing can continue as long as the vehicle is connected to the grid.

4. The advantages of Vehicle-to-Grid

For real estate
Vehicle-to-grid helps to balance acute electricity consumption peaks in the building with the help of electric cars; no additional energy from the grid is required. Especially in combination with a solar system.

For the power grid
If buildings can balance their electricity needs with V2G charging stations, this can relieve pressure on the electricity grid on a larger scale. This is especially practical when the amount of renewable energy in the grid generated by wind and solar increases. Without vehicle-to-grid technology, energy increasingly has to be bought from reserve power plants or from abroad, which increases electricity prices at peak times.

5. Does V2G affect car battery life?

However, battery wear as a cost factor is being challenged in recent studies. For example, it has been proven that an electric car battery does not wear out prematurely through continued use as a temporary power storage device. This applies to smart charging and discharging of the battery. The impact of V2G on the life cycle of EV batteries needs further investigation.

 

Sources

  • virta.global
  • wikipedia
  • energie-experten
  • carwow

Written by Carmupedia Editorial Office

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