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participate in V2G with fewer battery replacements over the vehicle’s lifespan. During the implementation
of V2G demonstration projects, priority should be given to BEVs with suitable battery capacities to
minimize the GHG emissions associated with V2G technology.

Based on the multi-scenario analysis, the environmental impacts of V2G are expected to improve
significantly with the ongoing expansion of renewable energy and the electrification of transportation. The
widespread adoption of LFP batteries will substantially reduce the additional carbon emissions associated
with V2G technology. Supplementary Figure 6 compares the results of this study with existing research on
the additional GHG emissions of stationary battery storage technologies. The results indicate that the
additional emissions from V2G are significantly lower than those from stationary storage technologies,
positioning V2G as a crucial energy storage solution for the future power system. The focus of this study is
the additional GHG emissions from EVs providing distributed energy storage services via V2G, without
accounting for the emission reduction benefits associated with the optimization of the overall grid system.
However, it is important to acknowledge that energy storage systems also play a role in reducing the overall
GHG emissions of the power system. On one hand, the integration of energy storage with renewable energy
generation helps to mitigate the intermittency and variability of resources such as wind and solar power,
thereby facilitating their integration into the grid and reducing the overall emission intensity of electricity.
On the other hand, traditional grid services are predominantly supplied by high-carbon thermal power
plants, while EVs and other battery storage systems provide a low-carbon alternative. According to the latest
report from the International Energy Agency (IEA), failing to achieve large-scale deployment of battery
energy storage systems within the power system represents a substantial risk to the clean energy
transition . In scenarios with low penetration of battery storage, the integration of photovoltaic (PV)
[39]
generation will face considerable obstacles, and a substantial portion of electricity demand will need to be
met by high-carbon energy sources, such as coal and natural gas. Under such circumstances, the
decarbonization of the power system is expected to decelerate around 2030, resulting in an additional 83 Gt
of cumulative global GHG emissions by 2050. This would substantially hinder the global target of limiting
the average temperature rise to 1.5 °C by the end of the century. In future research, a more comprehensive
evaluation of both the additional emissions and the system-wide emission reduction benefits will be
essential to better understand the potential of V2G technology in advancing the sustainability of the power
system.

CONCLUSION
This study focuses on the additional greenhouse gas emissions associated with electric vehicles providing
energy storage services by vehicle-to-grid technology. A data-driven life cycle assessment for vehicle-to-grid
technology is developed specifically for the Chinese market. The model integrates statistical data on various
factors, including China's EV market structure, driving behaviors, relevant policies, and geographical
indicators, enabling a comprehensive analysis of the geographical heterogeneity in lifecycle greenhouse gas
emissions of V2G technology at the city level.

The results indicate that the additional lifecycle greenhouse gas emissions associated with electric vehicles
providing frequency regulation as well as peak shaving and valley filling services in different cities range
from 0.046 to 0.152 kgCO /kWh and 0.036 to 0.148 kgCO /kWh, respectively. Among all components,
2-eq
2-eq
energy-related greenhouse gas emissions constitute the largest proportion, accounting for 59.0% and 66.8%,
respectively. Overall, the additional greenhouse gas emissions from vehicle-to-grid technology in China
exhibit a geographical distribution, with the lowest values in the southwest regions and the highest in the
northeast regions. The greenhouse gas emissions of vehicle-to-grid technology can be improved by cleaner
electricity generation, optimal battery capacities, and longer battery lifecycles. These findings provide