Rapid urbanization and rising motorization in South Asia demand scalable electric vehicle charging infrastructure that does not strain aging distribution networks. A case study of Bijoy Rakeen City, a dense residential community in Dhaka, tested whether hybrid solar-grid charging stations can meet future demand without substation upgrades.
Researchers designed an 80 kW charging station paired with a 20 kW rooftop photovoltaic array and modeled two adoption scenarios: a baseline reflecting current EV penetration and a stress test with 50 battery-electric vehicles (BEVs) and 40 plug-in hybrids (PHEVs). Using HOMER Pro software, they analyzed hourly load profiles derived from local surveys and projected charging patterns.
Results showed that peak charging demand could reach 40 kW under high adoption, consuming existing substation reserve capacity but remaining within safe limits. The rooftop solar system generated approximately 29,000 kWh annually, covering 51% of demand under moderate EV adoption and 22% under high adoption. This solar contribution substantially reduced grid purchase requirements and lowered operational costs compared to grid-only charging.
Cost-benefit analysis confirmed that distributed solar integration is economically attractive, reducing per-kilowatt-hour delivery costs and deferring capital expenditure on substation reinforcement. However, the study revealed an environmental trade-off: under Bangladesh's current grid electricity mix—dominated by natural gas and coal—EVs charged from the grid emit roughly twice the nitrogen oxides and sulfur dioxide of conventional gasoline vehicles. Solar-charged EVs avoided these emissions, underscoring the importance of grid decarbonization.
The findings suggest that hybrid solar-grid charging is technically feasible and cost-effective for dense South Asian cities, provided substations retain adequate reserve capacity. Policymakers should prioritize distributed renewable integration alongside EV incentives, while accelerating grid transition to renewables to unlock the full environmental potential of vehicle electrification. Further research should explore battery storage to shift solar generation to peak charging hours.
