If charged with green electricity, electric vehicles (EVs) can contribute greatly toward mitigation of greenhouse gas (GHG) emissions. To promote greener EV charging practices, this study proposes the environmental time-of-use (E-ToU) which provides time-varying prices and GHG intensity signals. Specifically, in E-ToU, GHG intensity is used as a nudge to steer drivers’ charging behavior, providing a mixed financial-environmental incentive. Conjoint-based choice experiments were conducted with participation of 1220 South Korean drivers (including 129 EV owners) to simulate EV charging under this novel scheme. Unit commitment was utilized to determine time-varying prices and GHG intensity, as well as evaluate the effectiveness of E-ToU. The results indicated that both charging costs and GHG intensity influenced the charging decisions (timing) of EV users. The E-ToU shifted EV charging to renewable-abundant daytime, reducing EV charging costs by 14.1 % and GHG emission from EV charging by 15.7 %. Additionally, it reduced the generation costs by 2.2 %, GHG emissions by 1.5 %, and renewable energy curtailments by 2.5 % in the power system. Notably, E-ToU outperformed flat-rate/ToU with respect to all evaluated metrics, highlighting its effectiveness. Therefore, this study recommends the mixed financial-environmental incentive approach for generating synergistic co-benefits for sustainability of power and transportation sectors.