Vehicle-to-grid (V2G) offers enormous potential for making the energy transition a success. How can electric cars be integrated into the power grid? What role do renewable energies play in the technology? Does V2G harm the battery of the electric car? In this article, you'll learn everything you need to know about V2G.
What does Vehicle-to-Grid (V2G) mean?
Vehicle-to-grid (V2G) is a form of bidirectional charging in which the flow of electricity between the power grid and the electric vehicle is possible in both directions. This means that the electric vehicle can not only be charged from the grid, but it can also be discharged, and the electricity fed back into the grid.
So in times of high electricity demand, the power grid can be relieved by taking the temporarily stored electricity from the electric vehicles. When electricity demand is lower and the price of electricity is cheaper, the vehicle can be recharged.
V2G makes it possible to use electric vehicles as decentralized buffer storage units that can temporarily store surplus electricity and make it available again as needed.
In this way, V2G makes a decisive contribution to the energy transition.
What are the challenges in deploying V2G?
- Poor infrastructure: One of the biggest challenges in deploying V2G is not the technology itself, but rather the infrastructure with which it interacts. Both vehicles and charging devices must be designed for bidirectional charging. However, V2G functionality is hardly widespread among German vehicle manufacturers so far. Asian vehicle manufacturers in particular are taking a pioneering role here. With regard to charging plugs, the CHAdeMo plug (widely used by Asian manufacturers) supports bidirectional charging, but the Type2 plug, which is widely used in Germany, does not support V2G. The European CSS plug is basically V2G-capable, but is currently still in the standardization phase.
- Fluctuations in the power grid: The feed-in of electricity from renewable energy sources has the disadvantage that instabilities can arise in the power grid. Renewable energies, such as solar and wind power, are subject to natural fluctuations due to weather conditions, because the sun does not always shine or the wind blow. This makes forecasts for energy from wind and solar all the more important, so that the volatility of these energy sources can be planned and used efficiently.
What are the benefits of using V2G?
- Reduced need for grid expansion and increased grid stability: In contrast to the grid fluctuations just mentioned, V2G can help make the power grid more stable. Grid constraints and sudden changes in energy supply can be responded to much more flexibly with the help of V2G.
- Increasing the share of renewable energy: V2G increases the use of renewable energy because the technology provides a way to store electricity from renewable energy sources in a more cost-effective way. If the sun shines or the wind blows at a location during the day, parked electric vehicles that are not being used can temporarily store the solar power generated and release it directly into the power grid in the event of a peak demand. In this way, more grid stability is provided by balancing supply and demand. The self-generated, temporarily stored electricity can also be used for the power supply at one's own location.
- Provision of backup power: If there is a power peak at the site, the power stored in the vehicle batteries can be used. In this way, the electric vehicles serve as electricity storage units, whereby they can be recharged when the demand for electricity drops. This is referred to as vehicle-to-home/ vehicle-to-building (V2H/ V2B), as the electric car acts as an electricity storage device for buildings and excess energy is fed into the building grid.
How can V2G be implemented?
- V2G-capable chargers: Chargers must be designed for V2G technology. V2G chargers are DC chargers that have a charging and discharging function. They bypass the unidirectional on-board chargers of e-cars and enable bidirectional charging.
- V2G-capable vehicles: For V2G, the vehicle must also be able to charge bidirectionally, i.e., receive energy and also send it back. Currently, the number of bidirectional vehicles is still manageable, but many vehicle manufacturers have announced steps toward V2G compatibility. All Nissan Leafs on the market, for example, can already be charged and discharged using V2G charging stations.
- A common communication protocol: In order for electricity to flow in both directions, a common communication protocol is needed so that vehicles, charging stations and utilities can communicate to send and receive required information for the V2G event. In April 2022, the European standard 15118-20 was adopted, which includes Plug & Charge and bidirectional charging. Currently, numerous research projects are underway with the goal of testing bidirectional charging technology.
Does V2G harm the vehicle battery?
Does V2G technology shorten electric car battery life? According to a study by the University of Warwick, V2G does not necessarily harm the battery health of an electric car, but can actually increase it:
Extensive simulation results indicate that if a daily drive cycle consumes between 21% and 38% state of charge, then discharging 40%–8% of the batteries state of charge to the grid can reduce capacity fade by approximately 6% and power fade by 3% over a three month period.
In a case study, using smart grid optimization, the power demand of a representative university office building was investigated. The result: the smart grid strategy is able to reduce the capacity drop of the electric cars by up to 9.1 percent and the power drop by up to 12.1 percent.
The future of V2G technology
A study by market research institute Ceresana calculates that new registrations for electrically powered vehicles (PHEVs and BEVs) in Europe will rise to over 8.7 million per year by 2030. For BEVs, this accounts for an average increase of 25 percent per year. Ceresana forecasts that there will be nearly 34 million BEVs on Europe's roads by 2030 (Elektrowirtschaft).
The global market for V2G technology was estimated at USD 1.77 billion in 2021. Precedence Research forecasts that it is expected to be worth around USD 17.43 billion by 2027, with a compound annual growth rate of 48 percent over the forecast period 2022 to 2027.
North America and Europe are the key regions in the global V2G technology market. The Europe V2G technology market was estimated to be worth USD 300.27 million in 2019. It is expected to grow at a CAGR of 46.06 percent from 2020 to 2027. The Asia-Pacific region in particular is predicted to see lucrative growth for V2G – countries such as China, Japan, India, and South Korea are striving to achieve green transformation.
The technical requirements for V2G are already in place, but they have not yet been fully implemented in the market, so further adjustments are needed. V2G is considered an important concept for the energy transition, because the technology allows e-vehicles to be intelligently integrated into the energy economy – keyword sector coupling.