The German company BMW is continuing the development of bidirectional technology on its electric cars. The system allows cars to return energy to the electricity grid if necessary. There are many examples: from the Vehicle-to-home architecture that uses the car as an energy storage system, in combination with an accumulator, to return energy to the home; or in combination with the photovoltaic system and the pre-setting of the recharge, to supply power to an external device or to an independent home.
BMW has delivered to some customers twenty i3 equipped with the new bi-directional technology, while another thirty will be delivered to business users in the coming weeks. The research project of the “Bidirectional Charging Management – BCM” consortium, launched in May 2019, aims to connect vehicles, charging infrastructures and electricity grids for the first time to facilitate the use of renewable energy – and at the same time increase the reliability of the energy supply. The research project will run for three years under the guidance of the German Aerospace Center and with funding from the German Federal Republic’s Ministry of Economy and Energy.
“Electric vehicles with bi-directional charging capability will not only be able to draw electricity for the high voltage battery when connected to a compatible charging station or wallbox, but will also have the ability to reverse the process and feed energy back into the electricity network of the distribution network operator. This will effectively transform electric vehicle batteries into mobile energy storage devices, capable of providing electricity when needed“, Remembers BMW.
The consortium behind the project is of considerable impact, in terms of names. Involved are: Kostal Industrie Elektrik GmbH (development of charging hardware), Keo GmbH (software provider for connecting user systems with energy suppliers), transmission grid operator TenneT and grid operator distribution network Bayernwerk Netz GmbH (both services of the energy system), the Research Institute for Energy and the Research Association for Energy eV (both the FfE research on the energy system and the impact on the network, and the evaluation of measurement), the Karlsruhe Institute of Technology (KIT; research on the electricity market and impact on the grid) and the University of Passau (user research).
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Customers will be provided with a technology ‘package’ to test. It consists of the in-vehicle and backend technology (BMW), the intelligent wallbox (Kostal) and the connection for the interconnection of the electric car, the wallbox and the electrical system in the customer’s building with the electricity grid (Bayernwerk, KEO and TenneT). The first direct effect for customers will be the maximization of the energy generated by their photovoltaic system in consumption, with a consequent significant reduction in electricity costs. This will be integrated in a second phase by the vehicle-to-grid (V2G) functionality, which means customers will be involved in new business models for energy trading and grid stabilization.
There will also be a third phase, which will extend the experimentation to customers with electric fleets, who will use their vehicles as short-term storage devices to eliminate peaks in energy consumption in the daily load cycle. BMW is also developing a system that can interrupt or reduce the energy required for recharging should the grid operator need it. Indeed, during periods when electricity demand is particularly high, these vehicles are able to feed additional energy into the grid, while high-voltage batteries are charged mainly at times when electricity from renewable sources is available or in demand. overall is lower.