With the rapid growth of China’s new energy vehicle market, the application of Vehicle-to-Grid (V2G) technology has become increasingly important for the construction of national energy strategies and smart grids. V2G technology transforms electric vehicles into mobile energy storage units and uses two-way charging piles to realize power transmission from the vehicle to the grid. Through this technology, electric vehicles can provide power to the grid during high-load periods and charge during low-load periods, helping to balance the load on the grid.
On January 4, 2024, the National Development and Reform Commission and other departments issued the first domestic policy document specifically targeting V2G technology – “Implementation Opinions on Strengthening the Integration and Interaction of New Energy Vehicles and Power Grids.” Based on the previous “Guiding Opinions on Further Building a High-Quality Charging Infrastructure System” issued by the General Office of the State Council, the implementation opinions not only clarified the definition of vehicle-network interactive technology, but also put forward specific goals and strategies, and planned to use them in the Yangtze River Delta , Pearl River Delta, Beijing-Tianjin-Hebei-Shandong, Sichuan and Chongqing and other regions with mature conditions to establish demonstration projects.
Previous information shows that there are only about 1,000 charging piles with V2G functions in the country, and there are currently 3.98 million charging piles in the country, accounting for only 0.025% of the total number of existing charging piles. In addition, the V2G technology for vehicle-network interaction is also relatively mature, and the application and research of this technology are not uncommon internationally. As a result, there is great room for improvement in the popularity of V2G technology in cities.
As a national low-carbon city pilot, Beijing is promoting the use of renewable energy. The city’s huge new energy vehicles and charging infrastructure have laid the foundation for the application of V2G technology. By the end of 2022, the city has built more than 280,000 charging piles and 292 battery swap stations.
However, during the promotion and implementation process, V2G technology also faces a series of challenges, mainly related to the feasibility of actual operation and the construction of corresponding infrastructure. Taking Beijing as a sample, researchers from The Paper Research Institute recently conducted a survey on urban energy, electricity and charging pile related industries.
Two-way charging piles require high initial investment costs
Researchers learned that if V2G technology is popularized in urban environments, it may effectively alleviate the current problem of “hard to find charging piles” in cities. China is still in the early stages of applying V2G technology. As the person in charge of a power plant pointed out, in theory, V2G technology is similar to allowing mobile phones to charge power banks, but its actual application requires more advanced battery management and grid interaction.
Researchers investigated charging pile companies in Beijing and learned that at present, most of the charging piles in Beijing are one-way charging piles that can only charge vehicles. To promote two-way charging piles with V2G functions, we currently face several practical challenges:
First, first-tier cities, such as Beijing, are facing a shortage of land. To build charging stations with V2G functions, whether leasing or purchasing land, means long-term investment and high costs. What’s more, it’s hard to find additional land available.
Second, it will take time to transform existing charging piles. The investment cost of building charging piles is relatively high, including the cost of equipment, rental space and wiring to connect to the power grid. These investments usually take at least 2-3 years to recoup. If retrofitting is based on existing charging piles, companies may lack sufficient incentives before the costs have been recovered.
Previously, media reports stated that at present, popularizing V2G technology in cities will face two major challenges: The first is the high initial construction cost. Secondly, if the power supply of electric vehicles is connected to the grid out of order, it may affect the stability of the grid.
The technology outlook is optimistic and has great potential in the long term.
What does the application of V2G technology mean to car owners? Relevant studies show that the energy efficiency of small trams is about 6km/kWh (that is, one kilowatt hour of electricity can run 6 kilometers). The battery capacity of small electric vehicles is generally 60-80kWh (60-80 kilowatt-hours of electricity), and an electric car can charge about 80 kilowatt-hours of electricity. However, vehicle energy consumption also includes air conditioning, etc. Compared with the ideal state, the driving distance will be reduced.
The person in charge of the aforementioned charging pile company is optimistic about V2G technology. He pointed out that a new energy vehicle can store 80 kilowatt-hours of electricity when fully charged and can deliver 50 kilowatt-hours of electricity to the grid each time. Calculated based on the charging electricity prices that researchers saw in the underground parking lot of a shopping mall in East Fourth Ring Road, Beijing, the charging price during off-peak hours is 1.1 yuan/kWh (charging prices are lower in suburbs), and the charging price during peak hours is 2.1 yuan/kWh. Assuming that the car owner charges during off-peak hours every day and delivers power to the grid during peak hours, based on current prices, the car owner can make a profit of at least 50 yuan per day. “With possible price adjustments from the power grid, such as the implementation of market pricing during peak hours, the revenue from vehicles delivering power to charging piles may further increase.”
The person in charge of the aforementioned power plant pointed out that through V2G technology, battery loss costs must be considered when electric vehicles send power to the grid. Relevant reports indicate that the cost of a 60kWh battery is approximately US$7,680 (equivalent to approximately RMB 55,000).
For charging pile companies, as the number of new energy vehicles continues to increase, the market demand for V2G technology will also grow. When electric vehicles transmit power to the grid through charging piles, the charging pile companies can charge a certain “platform service fee”. In addition, in many cities in China, companies invest and operate charging piles, and the government will provide corresponding subsidies.
Domestic cities are gradually promoting V2G applications. In July 2023, Zhoushan City’s first V2G charging demonstration station was officially put into use, and the first in-park transaction order in Zhejiang Province was successfully completed. On January 9, 2024, NIO announced that its first batch of 10 V2G charging stations in Shanghai was officially put into operation.
Cui Dongshu, secretary-general of the National Passenger Car Market Information Joint Association, is optimistic about the potential of V2G technology. He told researchers that with the advancement of power battery technology, the battery cycle life may be increased to 3,000 times or higher, which is equivalent to about 10 years of use. This is extremely important for application scenarios where electric vehicles are frequently charged and discharged.
Overseas researchers have made similar findings. Australia’s ACT recently completed a two-year V2G technology research project called “Realizing Electric Vehicles to Grid Services (REVS)”. It shows that with the large-scale development of technology, V2G charging costs are expected to be significantly reduced. This means that in the long run, as the cost of charging facilities drops, the price of electric vehicles will also drop, thereby reducing long-term use costs. The findings could also be particularly beneficial for balancing the input of renewable energy into the grid during peak power periods.
It needs the cooperation of the power grid and a market-oriented solution.
At the technical level, the process of electric vehicles feeding back to the power grid will increase the complexity of the overall operation.
Xi Guofu, director of the Industrial Development Department of State Grid Corporation of China, once said that charging new energy vehicles involves “high load and low power”. Most new energy vehicle owners are accustomed to charging between 19:00 and 23:00, which coincides with the peak period of residential electricity load. As high as 85%, which intensifies the peak power load and brings a greater impact to the distribution network.
From a practical perspective, when electric vehicles feed back electric energy to the grid, a transformer is required to adjust the voltage to ensure compatibility with the grid. This means that the electric vehicle discharge process needs to match the transformer technology of the power grid. Specifically, the transmission of power from the charging pile to the tram involves the transmission of electrical energy from higher voltage to lower voltage, while the transmission of power from the tram to the charging pile (and thus to the grid) requires an increase from a lower voltage to a higher voltage. In technology It is more complex, involving voltage conversion and ensuring the stability of electric energy and compliance with grid standards.
The person in charge of the aforementioned power plant pointed out that the power grid needs to conduct precise energy management for the charging and discharging processes of multiple electric vehicles, which is not only a technical challenge, but also involves the adjustment of the grid operation strategy.
He said: “For example, in some places, the existing power grid wires are not thick enough to support a large number of charging piles. This is equivalent to the water pipe system. The main pipe cannot supply enough water to all branch pipes and needs to be rewired. This requires a lot of rewiring. High construction costs.” Even if charging piles are installed somewhere, they may not work properly due to grid capacity issues.
Corresponding adaptation work needs to be advanced. For example, the power of slow charging charging piles is usually 7 kilowatts (7KW), while the total power of household appliances in an average household is about 3 kilowatts (3KW). If one or two charging piles are connected, the load can be fully loaded, and even if the power is used at off-peak hours, the power grid can be made more stable. However, if a large number of charging piles are connected and power is used at peak times, the load capacity of the grid may be exceeded.
The person in charge of the aforementioned power plant said that under the prospect of distributed energy, electricity marketization can be explored to solve the problem of promoting the charging and discharging of new energy vehicles to the power grid in the future. At present, electric energy is sold by power generation companies to power grid companies, which then distribute it to users and enterprises. Multi-level circulation increases the overall power supply cost. If users and businesses can purchase electricity directly from power generation companies, it will simplify the power supply chain. “Direct purchase can reduce intermediate links, thereby reducing the operating cost of electricity. It may also promote charging pile companies to more actively participate in the power supply and regulation of the power grid, which is of great significance to the efficient operation of the power market and the promotion of vehicle-grid interconnection technology. “
Qin Jianze, director of the Energy Service Center (Load Control Center) of State Grid Smart Internet of Vehicles Technology Co., Ltd., suggested that by leveraging the functions and advantages of the Internet of Vehicles platform, social asset charging piles can be connected to the Internet of Vehicles platform to simplify the operations of social operators. Build the threshold, reduce investment costs, achieve win-win cooperation with the Internet of Vehicles platform, and build a sustainable industry ecosystem.
Susie
Sichuan Green Science & Technology Ltd., Co.
0086 19302815938
Post time: Feb-10-2024
