The accelerating global transition toward low-carbon energy systems has positioned electric vehicles as both a major new load and a flexible distributed energy resource within modern power grids. Beyond their conventional role as transportation devices, electric vehicles increasingly participate in grid-to-vehicle and vehicle-to-grid interactions, enabling bidirectional energy exchange, demand-side flexibility, and ancillary service provision. This research article develops a comprehensive and theoretically grounded investigation of integrated grid-to-vehicle and vehicle-to-grid architectures, with a particular emphasis on optimization techniques, uncertainty management, and large-scale system implications under high renewable energy penetration. Drawing strictly on the existing scholarly literature, the article synthesizes insights from foundational smart grid studies, contemporary vehicle-to-grid modeling frameworks, photovoltaic-electric vehicle co-optimization research, profitability analyses under uncertainty, and system-level case studies from diverse geographical contexts.

The study advances the argument that grid-to-vehicle and vehicle-to-grid strategies must be conceptualized not merely as technical charging schemes, but as socio-technical coordination mechanisms embedded within evolving energy markets, regulatory environments, and renewable-dominated power systems. Methodologically, the article adopts a qualitative-analytical synthesis of optimization paradigms, including deterministic scheduling, stochastic optimization, information gap decision theory, and hybrid frameworks that account for uncertainty in renewable generation, vehicle availability, battery degradation, and market prices. Particular attention is devoted to the modeling of electric vehicle batteries, driving behavior, and state-of-health dynamics, recognizing their critical influence on the long-term feasibility of bidirectional grid participation.

The results section presents an integrated descriptive analysis of how coordinated charging, vehicle-to-grid aggregation, and virtual power plant configurations reshape load profiles, mitigate network congestion, and enhance renewable energy utilization across distribution and transmission levels. The discussion critically examines economic viability, battery aging trade-offs, and the role of policy and market design in enabling scalable deployment. Limitations associated with model assumptions, data uncertainty, and real-world behavioral variability are explored in depth, alongside future research pathways involving multi-energy systems, advanced forecasting, and digitalized grid control. The article concludes that electric vehicles, when systematically integrated through optimized grid-to-vehicle and vehicle-to-grid frameworks, constitute a cornerstone technology for resilient, renewable-intensive power systems, provided that technical, economic, and institutional challenges are addressed in a coordinated manner.