When Does Smart Charging Reduce Emissions? A Systematic Review of Behavioral and Structural Drivers

Global policy mandates accelerate transport electrification, yet the environmental benefits of smart charging (SC) and vehicle-to-grid (V2G) remain uncertain and context dependent. This systematic review synthesizes 88 peer-reviewed studies (2011 - 2025), retrieved through a dual-branch search combining sociotechnical adoption literature (Search A, n = 57) with environmental and grid-performance evidence (Search B, n = 31), to identify conditions under which SC and V2G are reported to deliver or fail to deliver sustainability benefits. The study proposes an integrated sociotechnical framework structured as a two-tier architecture: a parsimonious primary framework (seven constructs, six directed pathways) supported by classifiable evidence, and a hypothesis-generating extension for recurrent but unvalidated constructs. The framework is explicitly calibration-derived and requires future empirical validation. Evidence indicates that behavioral determinants are associated with participation intentions but are linked to actual participation only when structural conditions are present. Model-based evidence indicates that SC and V2G may increase emissions in high-carbon grids, demonstrating that these technologies are not inherently sustainable without aligned policy and energy system conditions. Four candidate contextual conditions including grid carbon intensity, infrastructure density, market maturity, and prior experience are recurrently identified as potentially conditioning deployment and emissions outcomes. These contributions shift policy discourse from overcoming user resistance to composing enabling conditions, offering context-dependent recommendations for deployment associated with measurable environmental benefits rather than unintended emission increases.