【Swapping Station: A Better Energy-Refilling Solution for Electric Truck?】
1. In China, heavy-duty electric trucks are in the momentum mainly due to the high transport efficiency over charging electric trucks, which drives the demand for more swapping stations.
2. The swapping station is considered the preferred solution for heavy-duty e-trucks and has the advantage of deployment in cold areas and plateaus. Tibet's Yulong Mines project is the highest-altitude swapping station project for battery-swapping trucks. Besides, swapping stations can be a foundation for a RE-microgrid at an industrial park to promote decarbonization.
3. The swapping mode faces mainly two bottlenecks: lack of standards and the commercialization problem. The first uniform bottleneck has been relieved by the 2023 launch of swapping specification standards. The other commercial bottleneck is about the heavy investment but can be mitigated by Vehicle-Grid-Integration operation, as well as government subsidies in some regions. NIO's swapping stations have successfully joined VPP events and possibly will trade at ancillary service markets in some pilot provinces such as Zhejiang, Shandong, Sichuan, etc.
Keywords: #ElectricTruck #Swapping #VGI #V2G #VPP
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In 2023 August, FotonDaimler launched its new battery-swapping electric tractor truck, Auman Zhilan (欧曼智蓝) in Beijing to catch up with the increasing demand for heavy-duty electric trucks under the decarbonization trend. Not only in closed scenarios such as ports, mines, and steel factories, Foton's new e-truck can also transport cargo for regional distribution and short trunklines with longer duration at a maximum power amount of 513kWh.
Figure 1. Auman Zhilan's e-truck is waiting to be loaded with new batteries.
Indeed, heavy-duty electric trucks have gradually become popular since 2020, mainly driven by the increasingly stricter vehicle emission regulation pressure, bringing up a penetration of 3.74% in 2022 to possibly 30% in 2030 in the Chinese heavy-duty truck sector.
Figure 2. Heavy-duty electric truck sales have grown steadily
As for the application, heavy-duty electric trucks in China have been used according to their mileage and carriage weight. Generally, they can be categorized into four types as required differently by scenario. The tractor e-truck can run 100-600km per time at a maximum power of 500-900 kWh, thus this type can be used for more areas than others.
Figure 3. Four types of heavy-duty electric trucks in China
In the unstoppable momentum of electric trucks, energy refilling has become a major issue for e-truck drivers and operators. Charging, as the typical solution, has the disadvantage of hours-long charging time but it is easier to deploy charging piles. On the other hand, a swapping station that only takes a few minutes to replace empty batteries with fully charged ones has emerged but it is costly to construct.
Figure 4. Two energy-filling solutions for heavy-duty electric trucks
In the trade-off between charging and swapping, swapping mode currently has an increasing number of supporters for heavy-duty electric trucks. This article first checks some real application cases of swapping stations for electric trucks and then discusses some methods to mitigate the bottleneck of swapping stations in China.
Momentum of Swapping for Heavy-Duty Electric Trucks in China
Generally, electric trucks are used in small-scaled scenarios, like mines or steel factories, so that they don’t need to be charged during the working process and can quickly go to the fixed charging point. However, swapping modes can extend trucks’ transport mileage to apply in longer-distance scenarios, such as some trunklines with fixed routes, because they can quickly refill electricity. Moreover, truck users can simply purchase trucks at a lower cost since batteries as the most costly component can be leased by battery suppliers or battery banks.
Such a swapping mode has proved practical and triggered the demand for battery-swapping trucks which can be refilled by both charging and swapping. In 2022, battery-swapping trucks represent around 50% of the 25,500 units of NEV trucks sold, 285% up from last year, and are expected to take more shares in the heavy-duty electric truck segment.
Figure 5. The increasing penetration of battery-swapping trucks
As mentioned, the explosive growth in battery-swapping trucks mainly comes from the time advantage. Swapping batteries can save 98% of the driver’s waiting time in comparison to charging batteries, leading to its efficiency optimization. This can be a decision-making factor for transport companies who are always hurrying to deliver cargo to destinations. Especially in cold regions, swapping mode is preferred as charging electric trucks can take longer time than in other areas because the electricity currents need to be lowered to protect lithium batteries.
Swapping Stations for Heavy-Duty Electric Trucks in Real Case
So far, China has practiced swapping stations in many extreme weather scenarios, for example, plateau mines. In 2021 May, State Grid EV Service company provided a fully automatic swapping station in Yulong Copper Mines (玉龙铜矿) in Tibet to support 40 dumping e-trucks. The swapping process only takes within 4 minutes.
Figure 6. CRCC 19th Bureau, GHAUL, and State Grid EV Service
Furthermore, since Oct. 2021, MIIT (工信部) has selected 13 cities to pilot swapping mode, including Changchun (长春) as the only one in the Northeastern region, which also implies the advantage of swapping mode in lower-temperature areas than charging.
SOJO Electric’s PV-storage-charging-swapping station
In 2022 August, SOJO Electric (双杰电气) deployed a PV-storage-charging-swapping station at its industrial park in Anhui. It is the example case of a heavy-duty truck swapping station to work as a microgrid. The swapping station aims to optimize the utilization of PV power to self-suffice the charging demand for batteries and save electricity costs while balancing power in microgrids.
At the SOJO factory, the rooftop PV of around 70,000 m2 generates 5.9MW power and 5.1GWh per year, whose power generation fluctuation issue can be mitigated by the swapping station. The battery swapping only takes within 3-5 minutes for 50-80 trucks per day.
Its subsidiary JJ Xundian (杰捷迅电) helps operators remotely control PV panels and swapping stations to switch from charging to releasing.
Figure 7. SOJO’s swapping station in Anhui
One noteworthy thing is that the PV and digital management platform are provided by SOJO's subsidiaries, which can work smoothly with SOJO's swapping stations. However, in China most swapping station constructors don't have the capabilities to self-develop or self-deploy distributed generators or energy management systems. Thus, these auxiliary areas that provide additional values for swapping stations can be ideal penetration segments for relevant players to catch up with the momentum of battery-swapping trucks.
Bottlenecks of Swapping Mode in China
However, the swapping station solution is still faced with some bottlenecks in China, one of which is the lack of unified swapping standards. As a result, various players enter this field as shown below and they develop swapping stations in their way and the incompatibility causes inconvenience for e-truck drivers. They can only use one brand’s swapping stations. It leads to limited application scenarios of battery-swapping trucks – so far they can only run within a small area or along fixed routes with directed swapping stations.
Figure 8. Market share of battery swapping trucks by OEMs
Currently, China Electric Heavy Truck Power Conversion Industry Promotion Alliance (中国电动重卡换电产业促进联盟) has been working on the unification of battery swapping for an estimated 5,000 swapping stations by 2025 to promote more e-trucks on long-distance transport. One founding member, the China Association of Automobile Manufacturers (中汽协) introduced a group-level standard, Technical Specification for the Construction of Electric Medium and Heavy-Duty Truck Sharing Swapping Stations and Battery-Swapping Vehicles (电动中重型卡车共享换电站建设及换电车辆技术规范) in 2022.
Another bottleneck is its heavy construction cost. One swapping station costs around RMB 1-2 million for passenger cars or RMB 23-25 million for heavy-duty electric trucks. To mitigate the construction cost of the swapping station, operation with the vehicle-grid-integration (VGI) function is the key part.
VGI: Cost Mitigation for Swapping Stations
In China, Vehicle-Grid Integration (车网互动) not only means smart charging but also V2G or swapping station-to-grid. Batteries can become external an energy resource to help the grid supplement electricity or adjust frequency. Given that China plans on 80 million electric vehicles hitting the road by 2030, EVs’ batteries, as well as swapping stations, can play a considerable role in stabilizing the grid system in the following three major ways:
Load modulation is the unique and most popular ancillary service across China. So far, multiple demo projects of smart charging / V2G load modulation have been conducted, mainly by grid companies.
Frequency modulation has been practically achieved in V2G projects.
In the long term, reserve capacity can be achieved by EV but as the current demo scale is limited, there is no related project.
Figure 9. Three major ways in VGI concept
Since 2022, several VGI cases have come out that involve swapping stations for passenger cars to help the grid system relieve electricity shocks and pressure. It is expected to see such a project in the heavy-duty electric truck sector too in the forthcoming future.
NIO’s Swapping Station in VPPs
In 2023 May, NIO’s swapping station joined a VPP event in Hefei, Anhui, to play the role of a storage system like a power station to provide ancillary services for the power grid to make additional revenue.
Figure 10. Overview of NIO’s Swapping Station in VPPs
Under Hefei State Grid’s Power Dispatch Center, the VPP has been launched since Feb. 2020 and accumulated a 220 MW capacity of PV stations, EV charging/ swapping stations (by NIO), storage systems, commercial buildings, etc.
The 2023 May VPP event adjusted the 5MW load in total during the 5 days. Each of NIO’s 15 swapping stations has 13 batteries to keep 600-700kWh storage capacity. When receiving VPP’s instructions, available batteries quickly responded to the grid system within 15 seconds to alleviate frequency fluctuations to keep around 50 Hertz. As a result, every swapping station’s charging voltage decreased from 630kW to 530kW. The whole process lasted for 5-10 minutes, leading to prolonged charging time by 3 minutes without any impact on EV users' experience swapping process. Through this AS service provision, NIO gets AS revenues though its amount is not disclosed. As a reference, Anhui has subsidized demand response between RMB 8-12/kW per time in 2022 and this may cover its VPP subsidy level, given that Zhejiang provides VPP subsidy at up to RMB 8/kWh in 2023.
Figure 11. NIO swapping station at Red Star Macalline (红星美凯龙) in Hefei’s Zhengwu district
According to Hefei’s three-year plan, the VPP will expand to cover 20% of the city’s summer load of 4GW in the future, which is equivalent to an 800MW-level traditional power plant. Swapping stations will become a type of highly flexible and reliable energy resource in the future.
Subsidy for Swapping Stations
Apart from benefits in operation, some cities provide subsidies in terms of construction and operation to help relieve investors' or operators' financial pressure in swapping stations. The construction subsidy is often one-time for swapping stations, ranging from 300 RMB/kW to 600 RMB/kW (≤ 1mn RMB/station) or a 30% refund of the total investment (1mn RMB/station). By contrast, the operation subsidy is usually based on the annual charging power amount (kWh), for example, 1.5k RMB/kW at the swapping station.
Figure 12. Subsidy and Ancillary Service Opportunities for Swapping Stations in China
As of 2023 June, swapping stations have been officially supported mainly in transport hub cities along trunk lines. These cities and provinces may be better locations for swapping station investors or operators in terms of cost mitigation. By comparing to the map of ancillary service markets for third-party players, Zhejiang, Sichuan, Shandong, Inner Mongolia, and Jilin can be considered as prioritized areas for swapping station business.
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