Study on the influence of EV charging facilities on peak load demands
Problems of EV charging development
Transportation shares 30% of the total global energy consumption, equivalent to the energy grid consumption. Total vehicle electrification means doubling the grid demand.
HK Government implements various policies to promote EV starting from 1994. The number of EV increases from 70 to 13,980 from 2010 to 2020. Now we have over 25,000 EVs and the number is growing fast.
Increasing EV charging demand will induce “hotspots” issue due to disorganized charging behavior/platform/frequency that utility and equipment upgrade is required.
Figure 1. Charging ahead: Electric-vehicle infrastructure demand.
Lacking EV charging infrastructure in HK
Low charger-EV ratio in HK at <1:5 discourages EV adoption
Very low quick chargers’ penetration due to grid capacity constraints
Charging capacity bottlenecks at old residential buildings
Problem Statement
EV Charging Load Demands increase the overall zone load demands significantly and might cause overload and safety issues.
EV Charging Load
Zone Substation Load Demands
EV Charging hotspots
1. Transformer at the building: near end-users, steps down voltage for local supply. Supports limited charging facilities.
2. Feeder: Transmits electricity from substations. Can support medium to high-power charging along its route (in commercial areas or major roads).
3. Zone Substation: Receives from transmission grid, steps down voltage for a zone. Ideal for large-scale charging hubs (in busy districts or hubs).
Execution Plan
1) Stochastic model of EV charging and hotspots identification: Develop a Stochastic model of the load profile according to the different levels of EV charging behaviour.
2) Capacity limits: Upon identifying the hotspots, the following should be studied: (a) maximum charging power allowed, and (b) different combinations of charging capacities.
3) Integration of the stochastic EV charging model, hotspots identification, and cloud based management platform. A cloud based management platform. will be designed and simulated. The core functionality of the software is to allow the site facility manager to scale and manage the network on-site properly, so the facility electricity and demand charge can be minimized.
4) Demonstration and experiment: Select a location as case study, rum simulation with different scenarios and combinations of charging facilities.
5) Documentation: After validating the test results in step 4, document the management platform. and algorithms, then write up the final report.