Batteries not only energize electric vehicles, but also supply energy to buildings and stabilize the power grid, through reciprocal charging systems.
Electrified vehicles are equipped with progressively more potent batteries, which can be recharged through a connection to the power grid or by using solar panels installed on rooftops.
This system can be used for home energy storage and also for linking the power grid through a two-way energy exchange that can lower energy bills.
How does it operate and are there any limitations or downsides?
What is bidirectional charging?
Batteries for electric vehicles from the charging station.
A fully charged battery can not only power the electric motor, electronics, lights, and heating but also external devices such as a refrigerator while camping, a drill on a construction site, or even another electric vehicle. These additional functions are referred to as V2D (vehicle-to-device) and V2L (vehicle-to-load).
These electrical vehicles can provide power to an entire building using vehicle-to-home (V2H), or power the public grid via vehicle-to-grid (V2G) technology. They can also charge car batteries.
Currently, bidirectional devices can only be found at select locations that provide charging stations.
What is the capacity of a car battery in terms of electricity storage?
The cost and capacity of batteries for Electric Vehicles (EVs) are decreasing. For instance, the Tesla Model Y comes equipped with a battery of at least 62 kilowatt hours (kWh), the VW ID.4 has a minimum of 77 kWh and the Renault R5 has at least 40 kWh on board.
In comparison, the electricity consumption of a two-person household in Germany is approximately 54 kWh per week. A mid-range electric car with a fully charged battery can fully cover this energy demand.
In addition, the new ID.4 and R5 models are already designed to power homes and supply electricity to the power grid.
With a bidirectional charging station, solar power can flow from a house’s rooftop into its car battery during the day, and then back into the building from the car in the evening. This allows residents to use inexpensive solar power both day and night.
Homeowners can link their electric cars to save on the cost of installing separate battery storage units for their solar systems. Typically, solar battery systems for single-family homes have a capacity of 5 to 10 kWh and can cost up to €10,000 ($10,440).
In particular,” said Robert Kohrs, an expert in smart energy grids at the Fraunhofer Institute, a German research body, “if done properly, controlled charging and discharging can extend battery life by 5 to 10%.
What benefits do electric cars have for the power grid?
In Germany, cars are driven on average for less than an hour daily. Meanwhile, when e-cars are stationary, grid operators can utilize their batteries to temporarily store excess electricity, thereby leveling out power fluctuations on the grid.
This will aid in utilizing the increasing amount of solar and wind power entering national grids effectively. In recent years, this has totalled 70% of the power generated in Denmark and slightly less than 50% in Germany – despite often being available during periods of low demand.
Currently, some communities in Europe can store excess electricity produced by its employing wind and solar energy. If there is peak energy demand, then the stored electricity is fed into the main power grid. This means there is less burden on gas or coal-fired power plants when electricity usage is high, also requiring less battery storage to maintain energy stability in the grid.
Annual savings of up to €22 billion could be achieved by sharing car batteries across Europe, as estimated by a study commissioned by the European environmental organization Transport & Environment.
According to the report, Electric Vehicles (EVs) can account for as much as 9% of the EU’s electricity needs, and potentially even up to a temporary 20%. This makes them a significant contributor to the overall electricity system.
This will necessitate the deployment of battery storage systems with a worldwide capacity of seventy-four billion kilowatt hours by the year twenty-fifty.
According to the researchers, there may be 1.5 billion EVs globally by 2050. With an average of 60 kWh of battery capacity per vehicle, the worldwide fleet of EVs could store a total of up to 90 billion kWh of electricity by then.
What are the advantages of car batteries for cars, residences, and the power grid?
According to the Fraunhofer study on electric vehicle power integration, e-car owners can save between €31 and €780 per year by sharing the battery power both at home and with the power grid.
In France, private owners of the new electric Renault R5 were offered 10,000 kilometers (approximately 6,200 miles) of complimentary driving electricity in exchange for connecting their vehicle to a bidirectional charging station for an average of 15 hours daily.
Raffeiner stated to that even more such offers are currently in development.
According to a survey commissioned by energy supplier E-on, 77% of respondents would utilize bidirectional charging technology to power their own buildings, while 65% would endorse electricity grid compatibility.
Experts propose that the next generation of public and private charging stations should be able to work in both directions wherever feasible.
This study by Fraunhofer estimated that this would raise the initial costs by approximately €100 for small charging stations (up to 22 KW), and by roughly €250 for a fast charging station.
However, these additional expenses would be compensated by the savings made within a few months of use.
