Operational strategies for EV fast-charging and their impact on power grid and renewable integration

Electric vehicles (EVs) are a transformative force in sustainable transportation, but their widespread adoption depends critically on the development of robust and intelligent fast-charging infrastructure. This paper presents a comprehensive review of EV fast-charging station (FCS) operational strategies and analyzes their multidimensional impact on modern power grids, focusing on grid stability, energy optimization, and renewable integration from 2014 to 2024. The review consolidates over 100 high-impact studies and technical databases. Our study identifies that FCS can recharge EVs up to 80% within 20–30 min, which significantly improves user convenience but simultaneously introduces peak demand surges, voltage instability, and transformer stress in distribution networks. Simulation results from referenced studies show voltage drops of up to 12%, with transformer aging rates increasing by 30–40% under uncoordinated charging scenarios. High-power charging stations (>350 kW) pose particularly severe challenges, requiring infrastructure upgrades and intelligent load management systems. This review further explores the strategic placement of charging stations using optimization techniques, including particle swarm optimization (PSO), genetic algorithms (GA), and Monte Carlo simulations. These techniques have demonstrated power loss reductions of up to 33% and improved voltage stability in modeled IEEE 33-bus systems. Additionally, integrating photovoltaic systems with battery energy storage systems can meet up to 69% of the station's energy needs, significantly reducing grid dependency. We also highlight emerging technologies, including vehicle-to-grid (V2G), dynamic pricing models, and AI-based predictive control systems, showing their potential to enhance both grid performance and economic viability. The review concludes by proposing a roadmap that combines operational strategy development, renewable integration, and smart grid control to support scalable and sustainable EV fast-charging infrastructure globally.