Upgrading of power grid

Background

In terms of electricity usage scenarios, we can roughly divide it into three stages. In the early applications of the power grid, its main supply targets were industries and conventional households. Due to lower industrial and living standards, the overall electricity demand was relatively low during this stage. The equipment and facilities of the power grid were relatively simple with lower performance at that time, and development and construction took place against this backdrop. With technological advancements, industrial electricity consumption rapidly increased, and the proliferation of various household appliances led to an expansion in residential electricity usage as well. As a result, the initially constructed power grid infrastructure including lines became inadequate to meet current electricity demands, leading to a second phase of upgrading and renovation.

In simple terms, it’s like an old house that is unable to handle the large number and high power of modern electrical appliances. To prevent any electrical safety accidents, it is necessary to remove the old circuits in the house and rearrange them.

Current Situation

Nowadays, the number of new energy vehicles in cities has reached a certain scale. The main power supply for the grid has also shifted from industrial and residential electricity to include electricity for industry, residents, and automobiles. If we simply convert the electricity used by cars into residential usage, it would be several times higher than the actual quantity. Let’s use approximate data for comparison: suppose the average battery capacity of a new energy vehicle is 70 kWh, with each charging session accounting for 50% of its total capacity (SOC ranging from 30% to 80%), which means each charging session requires 35 kWh. If an individual consumes an average of 10 kilowatt-hours per day, then one full charge of a new energy vehicle is equivalent to the daily electricity consumption of 3.5 individuals. In other words, when the number of new energy vehicles in residential areas reaches a certain scale, the “residential end” electricity consumption on the grid will be four to five times higher than before.

New Direction

Due to the complexity and scale of resources, costs, and time required for power grid transformation，a groundbreaking solution has been proposed through collaborative exploration across multiple industries. This innovative approach involves isolating the vehicle’s energy supplementation method before integrating it into the grid. The main idea is to transform existing charging stations into new integrated power systems that combine photovoltaic generation，energy storage，intelligent control，and charging capabilities。By isolating the charging network for vehicle energy supplementation，this solution ensures uninterrupted residential and regular industrial electricity supply。Additionally，by implementing an integrated system that combines solar power generation with storage capabilities ，surplus electricity can be effectively stored while achieving self-consumption of solar energy.

In terms of structure, it adopts a combination of a photovoltaic system, an energy storage system, and a microgrid, allowing the energy buffering function of the storage system to be integrated into the power grid. Finally, charging stations are connected to form a new type of intelligent charging network that can smooth out peak demand and fill in valleys.

It is worth noting that currently, very few of the “solar EV charging” integrated solutions available on the market include smart microgrids. Instead, they are simply applications of energy storage technology, which reduces the technical difficulty to some extent but increases the cost of storage and site requirements. Therefore, many charging station operators adopt this solution in order to reduce costs while achieving integration between vehicles and industries. The application of microgrids is essential for further cost reduction and achieving integration.

V2G

In addition to buffering vehicle energy consumption through energy storage systems, utilizing Vehicle-to-Grid (V2G) technology for energy interaction between vehicles and the power grid is also one of the technical means to achieve peak shaving and valley filling of the grid, based on the impact of new energy vehicles accessing the power grid

V2G refers to the process of using vehicle batteries to store electricity during periods of low grid demand and then releasing that energy back into the grid during peak demand or high-load periods through a technique called ‘vehicle-to-grid’ technology. For vehicle owners, this allows them to profit from buying electricity at lower off-peak rates and selling it back at higher peak rates, thereby reducing their overall cost of ownership. For the power grid, leveraging the flexible scheduling of vehicles with energy storage capabilities enables effective control over load management, reducing the need for investment in additional grid storage capacity.

According to the data, when the number of electric vehicles reaches tens of thousands, the application of V2G technology can provide megawatt-level power to the grid. However, when the number of electric cars reaches tens of millions, it can meet gigawatt-level power demand for the grid. Taking residential areas as an example, when 20% of electric vehicles participate in V2G applications, their grid load will transition from being overloaded due to uncontrolled charging to a baseline level.

We know that the number of charge and discharge cycles in the lifespan of a power battery is essentially fixed. Simply put, V2G technology involves continuously charging and discharging the power battery. However, frequent charging and discharging can accelerate performance degradation and shorten its lifespan. Because this technology affects battery life and performance, there are not many models supporting V2G technology for household vehicles; however, it has some support in commercial applications.