24.–26.05.2023 #polismobility

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Vehicle-to-Grid

When the electric car becomes an electricity pro

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Few people doubt that electric cars are already playing their part in transforming the transport sector. Some corporate partnerships are now taking this idea a step further and setting the course for full sector coupling. The company's own vehicle is taking on an unusual role here.

VW charging station Elli aims to optimize electromobility with the help of VG2 technology, among other things; the goal: power-saving, more sustainable energy generation. © Volkswagen AG

VW charging station Elli aims to optimize electromobility with the help of VG2 technology, among other things; the goal: power-saving, more sustainable energy generation. © Volkswagen AG

Just a few years ago, it would almost certainly have been an affront to describe driving a car - even an electric one - as a thoroughly sustainable way of getting around. There is no need to talk about gasoline-powered cars at this point, and even electrically powered vehicles, which at least did not emit any CO2 while driving, were completely dependent on the electricity mix of the respective state in which they were operating; and this was generally obtained only to a relatively small extent from renewable energy sources. The energy loss argument also became a permanent fixture in the e-debate, primarily for the reason that wind turbines or solar plants, for example, were and are often not built in areas where mobility pressures are particularly high, but rather on the periphery. In the near future, these two issues may now be resolved: Bosch, Nissan, Shell and VW subsidiary Elli are just a few of the numerous companies currently working flat out to develop concepts that will help acquit the electric car of almost all ecologically relevant charges. The keys to this: a modified charging cable and an intelligent system.

VW subsidiary Elli is currently developing a pilot project in smart charging together with EON subsidiary Mitnetz - also including V2G technology; the goal: grid-serving charging. © Elli

VW subsidiary Elli is currently developing a pilot project in smart charging together with EON subsidiary Mitnetz - also including V2G technology; the goal: grid-serving charging. © Elli

Smart Charging, Internet of Energy

i-rEzEPT uses V2G technology as it promises great potential in terms of electricity savings, among other things. © Nissan

i-rEzEPT uses V2G technology as it promises great potential in terms of electricity savings, among other things. © Nissan

This system enables communication between all the players involved via an Internet connection and coordinates them with each other - as long as the electric car is connected to the charging station. Based on the Internet of Things, which in simple terms represents the interface between online and offline, everything that happens within a smart energy system - from energy production and distribution to consumption - is referred to as the Internet of Energy. In the context of electromobility, this primarily involves a continuous exchange of data between the charging infrastructure, the electric car and the grid operator. A bidirectional charging cable is used for this purpose, which enables a two-way flow of electricity and data during the charging process and can therefore transport energy not only into the car battery, but also out of it and back into the grid. In this way, a new cycle takes the place of a one-sided charging process.

This technology, known as vehicle-to-grid, was already being tested in 2007 and is now already being used in some electric vehicles after the Nissan LEAF became the first model to receive its approval in 2018. In this process, excess electricity is "stored" in the battery until it is needed elsewhere; the "prosumer," i.e., the consumer who "produces" electricity at the same time, is compensated for feeding it back into the grid. In this way, the vehicle acts as a kind of temporary storage facility that can relieve the load on the power grid should supply ever be tight.

Efficient energy use - e-cars as distributed storage

Novel smart-charging technologies are now taking this a step further by not feeding excess electricity back into the grid but, if possible, not generating it at all by using intelligent algorithms to match planned charging operations with available grid capacity. In this way, vehicles are only charged when the electricity supply is high, such as at midday or when the wind is strong. In a broader sense, the Internet of Energy thus helps to increase energy efficiency, which includes sustainable generation as well as transport with as few losses as possible, but also responsible, economical consumption. In this way, the energy supply should become more reliable and flexible in order to meet changing requirements. All these different parameters - such as usage behavior and energy availability - are accurately coordinated. The goal is to use every available kilowatt hour of electricity as much as possible, at best no less and in any case no more, because currently around 6,000 GWh of renewable electricity is still being lost every year.

Likewise, Nissan and Bosch are integrating VG2 technology; such is the case with i-rEzEPT, which is researching the intelligent connection of automobiles to the power grid and aims to optimize it. © Nissan

Likewise, Nissan and Bosch are integrating VG2 technology; such is the case with i-rEzEPT, which is researching the intelligent connection of automobiles to the power grid and aims to optimize it. © Nissan

Dr. Martin Sachenbacher, an expert in energy storage and electromobility at the University of Lübeck and senior software engineer at LION Smart GmbH, sees great potential for electricity savings in V2G: "Technologies for the intermediate storage of electricity, such as V2G, can help here." But he cautions that this would require a corresponding proliferation of electric vehicle fleets and bidirectional charging infrastructure. Even though it will be one component of several, Sachenbacher expects "V2G to make a significant contribution to making better use of renewable electricity in the future."

Especially in light of the current energy crisis, which experts believe will continue for some time, more efficient energy use is essential. According to Sachenbacher, this will drive the expansion of renewable energies, but will also ensure a more fluctuating supply of electricity. "This is where V2G offers the potential to use electric vehicles as a large, distributed battery storage system to balance the fluctuating electricity supply and thus support the transition," Sachenbacher said.

Leading the way smart - exciting pilot projects

It may come as no surprise that the range of companies involved in the new technology is wide. Volkswagen subsidiary Elli, effectively the company's own energy company, is developing a smart charging pilot project in Saxony with regional grid operator Mitnetz, which in turn belongs to Eon, to encourage consumers to "charge in line with the grid" with the help of flexible prices. The company E-Bridge, which synchronizes the vehicles with the grid, rounds off the triumvirate. In this way, owners only recharge the amount of electricity they have actually used and receive it at good conditions, provided they charge in a consumption-conscious manner. The grid operator benefits by being able to use the vehicle as an electricity storage facility according to its own needs, and there are fewer bottlenecks in the grid during periods of high demand. The results of the pilot project are expected in fall 2022.

i-rEzEPT uses V2G technology as it promises great potential in terms of electricity savings, among other things. © Nissan

i-rEzEPT uses V2G technology as it promises great potential in terms of electricity savings, among other things. © Nissan

Bosch and Nissan have joined forces with the Fraunhofer Institutes IFAM and IAO to research the intelligent integration of automobiles into the power grid under the name i-rEzEPT. As part of the project, 13 home owners who have a photovoltaic system were provided with a Nissan LEAF and a charging station. The goal of the project: to make the most of the household's supply of self-generated electricity, to help relieve the strain on the public power grid, and to reduce the operating costs of the electric vehicle in the process. Under the term vehicle-to-home, in addition to storing the energy in the vehicle, it is also possible to deliver it to the household and operate electrical appliances without a load on the power grid. The future viability of the bidirectional charging infrastructure therefore does not end with feeding the electricity back into the grid or adapting the charging behavior to external circumstances at any given time, but also makes itself felt in the home.

i-rEzEPT uses V2G technology as it promises great potential in terms of electricity savings, among other things. © Nissan

i-rEzEPT uses V2G technology as it promises great potential in terms of electricity savings, among other things. © Nissan

Shell Recharge Solutions is also committed to V2G technology and is conducting a pilot project in collaboration with Mitsubishi, TenneT, Enel and Nuvve to demonstrate the benefits of smart technology. Here, too, the goal is to ensure intelligent sector coupling and correspondingly balanced load control in the power grid. For example, Mitsubishi's Outlander Phev ESUV in the Netherlands can already contribute to a balanced power grid with the help of vehicle-to-grid, storing as much energy in its 12-kilowatt-hour battery as an average family uses per day. At midday, solar energy production peaks are absorbed and fed back into the power grid during the evening demand peak. If vehicle owners have access to bidirectional charging stations at home and at work, 70% of all vehicles could be used to store excess energy. Monetary benefits for consumers are also envisaged here.

If nationwide provision of both public and private charging stations - and above all the vehicles themselves - with the infrastructure for smart charging becomes established, the electric car can significantly increase its share of the transformation. German and European manufacturers and utilities are currently building more and more coalitions to test and improve the system. According to forecasts, it will take time before all the legal and financial issues are resolved; however, the trend in the electrified mobility industry is clearly pointing in the direction of vehicle-to-grid technology. In Dr. Martin Sachenbacher's view, there is a need for action above all in secure communication and efficient control of the overall system. He also says that it still needs to be clarified who is liable in the event of failures, how faults can be reliably detected, and how exactly the billing of the electricity fed back into the grid works. "From my point of view, we can therefore expect to see solutions on a local scale first," Sachenbacher summarizes. The coming years will now provide information on when consumers can expect to see their vehicles being transferred to the smart charging circuit across the board.

Author

David O‘Neill