Smart charging: How EVs can cut emissions by charging smarter, not less

Electric vehicles (EVs) are crucial for sustainable transport, but their environmental benefit depends heavily on when they charge. Charging during periods when the grid relies on fossil fuels can significantly increase their carbon footprint. New research from Multimedia University reveals that "carbon-aware" charging strategies can unlock substantial emission reductions simply by optimizing charging times.

The study, led by Md Sabbir Hossen and Gobbi Ramasamy from Multimedia University, quantifies the real-world carbon emission reduction potential of smart EV charging. Researchers reconstructed hourly residential charging data and combined it with time-varying grid carbon intensity from the Malaysian Peninsula power system. They then evaluated a reinforcement learning-based carbon-aware smart charging strategy, comparing its performance against both uncontrolled charging and an intelligent but carbon-unaware charging approach, all while delivering identical total energy.

The Power of Carbon Awareness

The findings are compelling: while intelligent charging without carbon awareness failed to reduce total carbon emissions, the carbon-aware strategy achieved a statistically significant reduction of approximately 1.62%. This crucial difference comes from proactively shifting charging demand away from periods when grid electricity is most carbon-intensive. Specifically, evening peak hours were found to be approximately 18% more carbon-intensive than off-peak periods, making targeted load shifting highly effective.

The Multimedia University team demonstrates that these emission reductions are driven purely by temporal redistribution of charging demand, meaning no changes to physical infrastructure or reductions in delivered energy are required. This highlights a powerful, yet often overlooked, mechanism for decarbonization within existing urban power networks.

Scalable Solutions for a Greener Future

While a 1.62% reduction at a single residential feeder might seem modest, its impact becomes profound when scaled. Extrapolating to 2,000 similar urban feeders, this approach could prevent over 1,000 metric tons of CO₂ emissions annually. This makes carbon-aware charging a complementary and effective tool alongside other decarbonization efforts, such as renewable energy integration and time-of-use pricing. It specifically addresses the demand-side operational challenge of aligning energy consumption with cleaner supply.

Refining the Road Ahead

Despite its practical benefits, this study, like any, has specific parameters. It focuses on a single residential charging site and historical carbon intensity data, without considering electricity cost optimization. Future research could expand to multi-site networks, explore vehicle-to-grid (V2G) interactions, and integrate local renewable generation and energy storage. Additionally, developing multi-objective strategies that balance carbon reduction, cost, and user convenience will enhance real-world applicability.

Suggested author quote for approval:

"Our research unequivocally shows that the timing of EV charging is as critical as the charging itself for reducing emissions," states Professor Gobbi Ramasamy, a corresponding author from Multimedia University. "By integrating real-time carbon signals into smart charging decisions, we can achieve meaningful, scalable carbon reductions without compromising user convenience or requiring costly infrastructure upgrades. This is a vital step toward sustainable urban mobility."

Corresponding Author: Gobbi Ramasamy

Original Source: https://doi.org/10.1007/s44246-026-00280-6

Contributions: Md Sabbir Hossen conceived the study, performed the data analysis, developed the methodology, and prepared the manuscript draft. Md Tanjil Sarker contributed to the modelling framework and validation. Gobbi Ramasamy and Ngu Eng Eng provided supervision, critical review, and interpretation of results. All authors read and approved the final manuscript.