Analysis of EV Charging scenarios and impact on power grid

Home Charging: Risks and Opportunities
Home charging of EVs poses a significant risk of overloading the distribution transformers and feeder loading. However, the report identifies off-peak charging as a viable solution to mitigate this risk. By shifting the load to off-peak hours, not only can overloading be avoided, but it also allows for the reduction of variable renewable energy (VRE) curtailment.

Workplace Charging: A Sustainable Approach
Charging EVs at workplaces presents a lower risk of overloading due to the typically larger capacities of commercial or industrial zones. This scenario also offers the potential to increase the consumption of solar power, due to the prevalence of daytime connection, adding a layer of flexibility to the power grid.

Public Roadside Charging: Balancing Demand and Supply
The CEA report highlights that public roadside charging, particularly with high-power draws from three-phase charging, could lead to overloading issues similar to home charging. Nevertheless, it also presents an opportunity to boost the consumption of renewable energy generation, leveraging the usual daytime connection.

En Route Charging: High Power, Limited Flexibility
Charging EVs en route, such as on highways, could necessitate high power draws. This scenario might require dedicated transformers or stationary storage as buffers. However, there is limited scope for demand response flexibility due to the typically short or non-existent surplus connection time.

Depot Charging: High Demand, Strategic Management
Depot charging, used for larger volumes and numbers of vehicles, is expected to draw significant power. This might necessitate dedicated substations, which could be viable given the commercial nature of the operation. Challenges include potential land use restrictions for network upgrades in urban areas. On the upside, fleet predictability and load management present high potential for load shifting, VRE curtailment reduction, and bidirectional charging.

Battery Swapping: A Controlled and Efficient Approach
The battery swapping model introduces a controlled charging process, reducing the risk of overloading. It allows for 24/7 bidirectional interaction with the grid and facilitates the use of VRE. Additionally, this approach aids in battery charging management, potentially reducing the ageing of assets.

In summary, the CEA report comprehensively outlines the varying impacts and opportunities of different EV charging scenarios. While each scenario presents its unique challenges, there are also distinct opportunities for integrating V2G technologies to enhance grid stability and promote the use of renewable energy. The report underscores the need for strategic planning and management to optimize these opportunities while mitigating risks.

Source: Electric vehicles utilisation for v2g services | Reported by Central Electricity Authority