V2G is the term used to describe the process by which electric vehicles (EVs), in addition to charging electricity from the grid, can also discharge. Vehicle batteries can stabilize the grid in the event of excess or inadequate power generation or when power lines are too overloaded to transport electricity to consumers. The technology will address the key challenge in the energy transition that relies on renewable (non-dispatchable energy) sources. They cannot adjust their power production according to electricity demand but must rely on flexible consumers and energy storage units to match electricity supply and demand. The EV can provide this flexibility by charging during times of abundant electricity and discharging during times of scarcity. The concept has been extensively discussed in the literature. However, the real-world application of the image is largely limited by small demonstrations and trial projects [ 1 2 3 4]. In recent years, several actors in the industry have developed products and services to implement bidirectional charging for EVs. Since 2001, when the term “vehicle-to-grid” was first coined [ 5], this development has been closely tracked by academia and industry. The most common is to assess the economics. Steward [ 6] reported in 2017 that the expected profitability of studies varying between USD 4/a to USD 3320/a was a major divergence. The wide range in values can be explained by the different assumptions and markets vehicles are involved in. Heilmann and Friedl [ 7] found that the beliefs and needs could be classified into four categories: market conditions, technical requirements, costs, and controls. The study also confirms that there is a wide range of revenue and business cases. Some cases have losses up to EUR 700/a, while other studies show revenues of EUR 5,200. Ravi and Aziz have surveyed to determine the type of services that vehicles provide to grids. The authors point out that vehicle-to-grid is just one aspect of a broader category called vehicle-grid Integration, which includes smart charging. The authors confirm that, in practice, the term “vehicle-to-grid” has almost become synonymous with “vehicle-grid integration.” Researchers have also begun to focus on more specific topics in addition to the more general ones. Many works focus on particular countries, such as Indonesia , China[10,11], Germany, the Netherlands, etc. The economic analysis also has a marketing aspect: the marketing of the V2G concept to potential users. Baumgartner et al. [ 14] used a survey approach to ask people with different levels of experience in EVs. The researchers found that climate-neutral charging and a minimum range remaining in the vehicle were key motivators, even though they resulted in a lower financial reward. Bohdanowicz et al. [ 15] show an even more varied motivation landscape. They find that the size and type of financial incentives do not have a direct relationship to the willingness to take part in V2G schemes. They claim that altruistic and intrinsic motivations are important. Lehtola et al. In 2019, [ 16] published an early review that confirmed what later studies have repeatedly confirmed: smart and bidirectional chargers can reduce battery aging compared to charging the vehicle after it has reached a full charge. Calearo and Marinelli demonstrate that the additional aging of extensive V2G operations over five years results in a net profit of approx. EUR 3500 for each vehicle during the period given [ 17, 18]. With the constant changes and announcements, it isn’t easy to get a clear picture of the state of the industry. The research papers and market reports [19-20,21-22] focus primarily on the electric car market, but the V2G topic is often only mentioned as an aside. Research that focuses on V2G faces a challenge in keeping up with the fast-paced market. Das et. Three years after Das et al. This paper aims to provide an analysis of V2G, including the latest developments in markets, regulations, and technology. We have focused on Europe to analyze the state of readiness of the regulatory bodies, as well as the bidirectional vehicles and available charging stations. Germany is the largest car market in Europe, based on the number of cars sold. We hope to help both practitioners and researchers with this report by providing clarity on the technologies and capacity available now and – extrapolated – in the future. This submission will give a realistic view of the market dynamics for actors who are interested in raw material demand and manufacturing volumes.
Materials and Methods
This paper is based upon two major pieces of work: extensive research to gather data about the readiness and availability of regulatory frameworks for vehicles, chargers, and charging stations, as well as data analyses for German market analysis.
2.1. Literature Review
The Mobility House conducted the Literature Review for this Paper in April 2023. Product catalogs and field test reports are the main sources of data. Due to the method of data collection, the list of models of cars and charging stations may not be complete, and the evaluation of regulatory states by country may contain partial, subjective assessment. The two do not claim to be finished, and the market is constantly changing.
2.2. Data Analysis
This paper presents an analysis of data previously collected and reported in 23. The interactive version is available in 25 ]. RWTH Aachen performed the work. The data collection method will be briefly described in this article for the sake of clarity. Readers can also refer to 23 ]. For the years observed, the car registrations were retrieved from the German Federal Office for Motor Traffic (in Flensburg, Germany, “Kraftfahrtbundesamt,” KBA) [ 26 The ADAC has merged the ADAC’s technical data catalog with that of the General German Automobile Association (ADAC). 27 ]. Using this method, it is possible to determine the DC fast-charging connectors, battery capacity, and charging power for many car models. The KBA doesn’t assign model identifiers to vehicles that are not very different. The number of cars to which we were able to give technical characteristics did not match the actual registered number of battery electric vehicles and plug-in hybrid electric vehicles. Scaling was done for each data point. The plots in this article are based on different primary sources of data. We report each data source separately in the caption.
Four sections are presented. The first two sections, “Overview V2G readiness of the regulatory framework” and “Overview V2G readiness by hardware provider”, are focused on what’s currently possible with regard to regulation, vehicles, and charging stations. The majority of devices are in an early stage and haven’t yet made a strong impact on the market. Many of the bidirectional vehicles we identified are only capable of supplying loads as a vehicle to load setup, or they only support V2G during field testing. These two options do not provide a V2G solution that is ready for the customer. The last two sections, “Electric Vehicle Sales in Germany” and “Properties of BEVs sold in Germany,” focus on the whole fleet of BEVs in Germany and not just on those with bidirectional charging capabilities. In order to support the topic, an analysis of the existing fleet was conducted. The focus of this analysis was on the effect and implications of the analyzed vehicle characteristics for a V2G.
3.1. Overview of the V2G Readiness of the Regulatory Framework
A technical solution is not enough to make V2G possible. The regulatory environment must also be set up in a way that allows vehicles to interact with grids and electricity markets. In Europe, there are three main obstacles to market adoption:
- Taxation of consumption
- Electricity consumption in many European countries is only measured by kWh. There are also significant taxes and levies on the energy consumed. For example, in Germany, electricity prices have been around EUR 30 ct/kWh over the past decade [ 28], while wholesale power costs were between EUR 4 and 5 ct/kWh. It was, therefore, impossible to make a business case for selling heavily taxed power back into the grid. This ratio has changed a little since the energy crisis began in 2021. However, without any changes to market rules, creating a business case was nearly impossible. This problem can be overcome by compensating taxes and levies in proportion to the amount sold back to the grid. In Germany and other European countries, this approach is being used. Arbitrage trading is then possible.
- Grid codes are fulfilled.
- Grid codes were often designed for large stationary power producers. The concept of an asset that can feed electricity into the grid from different locations was not anticipated in many laws. The fact that power generators behave differently in Europe when faced with short circuits, voltage drops, and other grid irregularities is part of the problem. This is not an issue for DC bidirectional charging since grid codes can easily be provided to the DC/AC Converter inside the DC charging station. The vehicle’s behavior would change if it were to use AC-bidirectional charging. ISO 15118-20 allows this behavior, but few charging stations can actually implement it at this time. It is common to limit bidirectional charging to one charging station. [ 31]. Appendix A contains more information on this topic.
- Measurement of energy delivered
- The measurement and billing for delivered energy is part of the market interaction. Smart meters are usually used to achieve this. These devices are deployed in different ways across Europe. The Nordics, Italy, France, and some smaller countries lead the way with approximately. Ninety percent or more of households have such a device [ 32]. Other countries, such as the United Kingdom (49 percent at the end of 2021 [ 33]) or Germany (0 percent at the 2021 end [ 33]), are far behind. Germany has recognized this problem, and the new Smart Meter Law ([ 34]) allows households to install a smart meter for a maximum of EUR 20 per year. One can be optimistic about the improvement of many European countries in this area. A smart meter is essential for economic operations. Without it, they are often restricted to options behind the meter, such as optimizing self-consumption from onsite PV generators. However, systematic benefits can be harder to capture.
Table 1 This chart shows how each European country is progressing in adopting V2G regulations. Many relevant markets have adopted laws that make V2G feasible in a market-based environment. However, at the time this article was written, no country had achieved complete Integration. Table 1. The ten countries that will sell the most BEVs in 2022. Details on specific countries can be found at 35 ]. The data was collected in April 2023. The statements in this chapter are not dependent on the type of market the vehicle is interacting with. The severity of the issues affects markets differently. Below is a brief overview of two relevant markets – wholesale electricity markets and frequency restauration markets – as well as the challenges they face. Table 2. Other service markets, like black start, capacity market, dispatch, etc., are not included as they are less important in volume than the ones discussed. Table 2. The two main markets, wholesale and frequency restoration services, are facing significant regulatory challenges.
3.2. Overview of the V2G readiness of hardware suppliers
The market is dynamic, with many manufacturers entering the V2G sector. This includes both vehicles and charging stations. Table 3 This overview shows which cars can be trusted in both directions. Table 4 Chargers are also included in this category. Data collection took place in April 2023, and since then, newer products have been released. Note that bidirectional charging is not a guarantee that the vehicle or station can perform this service with an off-the-shelf configuration. There are limitations, especially for the cars: Many of the vehicles are only able to supply power when they are connected to the grid in a car-to-load mode (e.g., Ioniq 5, 6, BYD Atto3, NIO EL7, etc.). Others have only been tested as V2G (e.g., Fiat 500e, BMW i3). The list of V2G-enabled vehicles is shorter. The list of cars that use the CHAdeMO connector, such as the e-NV200 or Leaf, iMiEV, or Outlander, have been able to discharge into the grid for years. However, the list of CCS-based vehicles with bidirectional capabilities is much smaller and includes the F-150 ID. Buzz or EX90. Note that V2G hardware’s response time is too slow for highly dynamic markets, such as the frequency containment reserves.