Electric vehicle V2G technology refers to the technology of electric vehicles to supply power to the power grid, and its core idea is to use the energy storage of a large number of electric vehicles as a buffer for the power grid and renewable energy.
Vehicle-to-Grid (V2G) is an emerging energy management technology that connects electric vehicles (EV) to the power grid to achieve two-way energy exchange. Traditionally, electric vehicles only obtain energy from the power grid for power supply, while V2G technology allows electric vehicles to feed excess power back to the power grid for use by the power grid, thereby achieving a two-way flow of energy.
The current power grid is actually not very efficient because of the high cost and easy waste. Part of the problem is caused by daily fluctuations in load demand and the need for voltage and frequency regulation of the grid. When grid demand exceeds the capacity of base-load power plants, peaking plants are brought into operation, sometimes with spinning reserves involved, as the grid itself does not have sufficient energy storage. When demand on the grid is low, electricity usage is lower than the output of base-load power plants, and any unused energy is wasted. In addition, voltage and frequency regulation of the grid increases the operating costs of the grid to a large extent.
Renewable energy systems (such as solar energy, wind energy, etc.) are being connected to the power system in large quantities. Since the natural discontinuity of renewable energy can cause fluctuations in power generation, there is an urgent need for compensation from other energy sources (such as battery energy storage systems) to smooth the natural variability of renewable energy, ensure the stability of the grid frequency and suppress the effects of reverse power. voltage rise caused by current.
The concept of V2G was proposed in response to the above problems. Its core idea is to use the energy storage of a large number of electric vehicles as a buffer for the power grid and renewable energy. When the grid load is too high, the electric vehicle energy storage feeds power to the grid; when the grid load is low, it is used to store the grid's excess power generation to avoid waste. In this way, electric vehicle users can buy electricity from the grid when the electricity price is low and sell electricity to the grid when the electricity price is high, thereby obtaining certain benefits.
Now, plug-in hybrid electric vehicles (PHEV) and pure electric vehicles (EV) are slowly entering the market. Since these cars are equipped with larger-capacity batteries, they can be considered to provide an energy buffer for the grid when parked. Since most cars are parked for approximately 22 hours a day, during this time they represent a an idle asset. And when the number of these cars is large enough, the total capacity of their batteries is so huge that they can be used as a buffer for the grid and renewable energy systems.
However, electric vehicles cannot be connected to the power grid at will and without management. This is because if the power grid is at peak load demand, the charging requirements of a large number of cars will inevitably have an extremely serious impact on the power grid; for cars, In addition to providing auxiliary services to the grid, it must also be able to meet daily driving needs. Therefore, in the process of feeding power to the grid, the energy storage status of the car itself must also be taken into consideration to avoid affecting the normal use of the car. Based on the above two aspects, it is very necessary to conduct research on V2G of electric vehicles to coordinate the charging and discharging between the vehicles and the power grid so that it will neither affect the operation of the power grid nor limit the normal use of the vehicles.