Prof. Hsieh's Ph.D. work on China's transition to electric vehicles is live on MIT News.

Before founding the E3 group at NTU, I-Yun Lisa Hsieh — then a doctoral researcher at the Massachusetts Institute of Technology (PhD '20) — worked with Professor William H. Green (Hoyt C. Hottel Professor in Chemical Engineering and co-director of the MIT Energy Initiative's Mobility Systems Center) on a question with global stakes: what will China's electric-vehicle mandate actually cost — and will it work? The research, conducted under the MIT Energy Initiative's Mobility of the Future study, was featured twice by MIT: in the Energy Initiative's magazine Energy Futures in late 2020, and by MIT News in April 2021 — by which time she had joined NTU as an assistant professor.

The Research

China's mandate — reaching for new-energy vehicles to make up 40% of car sales by 2030 — is among the strongest EV policies in the world. Across four peer-reviewed papers, the research built an integrated techno-economic picture of what that transition entails:

• Modeling uncertainty in China's private car-sales trajectory (Transportation Research Record, 2018);
• Practical limits on battery price reduction (Applied Energy, 2019) — showing that learning-curve gains in lithium-ion NMC battery manufacturing slow as prices approach the floor set by raw-material costs;
• Implications for private motorization rate and battery market (Energy Policy, 2020);
• Total cost of ownership under the transition (SAE International Journal of Sustainable Transportation, 2020) — finding that hybrids reach cost parity with gasoline cars once purchase subsidies lapse, while pure battery EVs remain more expensive through 2030.

The headline projections: roughly 66 million EVs sold in China across the 2020s, reaching a 37% sales share (11.2 million vehicles) by 2030 — just shy of the mandate's target — at a societal cost averaging about 100 billion yuan per year, on the order of 0.1% of China's GDP. "The benefits appear to be the same order of magnitude as the costs," Prof. Hsieh noted in the MIT News story. "It's so close that we need to be careful to get the numbers right."

From Cambridge to Taipei

That doctoral work became the intellectual foundation of the E3 group. The same integrated lens — technology cost curves, consumer economics, and policy design analyzed as one system — carried into Prof. Hsieh's first Taiwan research grant on computer-aided assessment of green transportation policies, and has since grown into the lab's research on scooter fleet electrification, battery swapping, and Vehicle-to-Grid integration — bringing the questions first asked about the world's largest car market home to Taiwan's distinctive mobility landscape.

Read more: the original features on MIT News and in MITEI's Energy Futures