Electric Vehicle V2G Technology

The current power grid is actually not very efficient, because first, the cost is higher, and second, it is easy to cause waste. Part of this problem is caused by the large fluctuations in load demand that occur and the need for voltage and frequency regulation of the grid. When grid demand exceeds the capacity of baseload power plants, peaking power plants are put into operation because the grid itself does not have sufficient electrical energy storage, and sometimes spinning reserves are also involved. When grid demand is low, electricity usage is lower than the output of baseload power plants, so that unused energy is wasted. In addition, the voltage and frequency regulation of the grid increases the operating cost of the grid to a large extent.
Renewable energy systems (such as solar, wind, etc.) are being heavily integrated into the power system. Since the natural discontinuity of renewable energy can cause fluctuations in power generation, other energy sources (such as battery energy storage systems) are urgently needed to compensate, to smooth the natural variability of renewable energy, guarantee grid frequency stability and suppress the reverse power caused by reverse power. The voltage rise caused by the flow.
The concept of V2G is proposed in response to the above problems, and its core idea is to use the energy storage of a large number of electric vehicles as a buffer for the grid and renewable energy. When the grid load is too high, the energy stored by the electric vehicle is fed to the grid; and when the grid load is low, it is used to store the excess power generation of the grid to avoid waste. In this way, electric vehicle users can buy electricity from the grid when the price of electricity is low, and sell electricity to the grid when the price of electricity from the grid is high, so as to obtain certain benefits.

Now, plug-in hybrid electric vehicles (PHEV) and pure electric vehicles (EV) are slowly entering the market. Since these cars have larger capacity batteries, consider having them provide an energy buffer to the grid when parked, as most cars are parked for approximately 22 hours each, during which time they represent An idle asset. And when the number of these cars is large enough, the total capacity of their batteries is so large that they can be used as a buffer for the grid as well as the renewable energy system.
However, electric vehicles cannot be connected to the grid at will and without management, because if the grid is in peak load demand, the charging requirements of a large number of vehicles will inevitably have an extremely serious impact on the grid; for vehicles, In addition to providing ancillary services to the grid, it must also be able to meet daily driving demands. Therefore, in the process of feeding power to the power grid, the energy storage state of the car itself must also be taken into account to avoid affecting the normal use of the car. Combining the above two aspects, it is very necessary to study the V2G of electric vehicles, and coordinate the charging and discharging between the vehicle and the power grid, so that it will neither affect the operation of the power grid nor limit the normal use of the vehicle.

Post time: Jun-09-2022