Mehrdad Ehsani

Presentations:

A Global Perspective on Sustainable Energy and Transportation

There is plenty of hydro-carbon energy available on earth, for hundreds of years. The urgency of sustainable energy and sustainable transportation technologies is due to population growth, global warming, and equitable access to energy for all humanity. The way forward is to help the developing world (90% of population that dominates the future emissions) with “clean” energy and transportation, rather than making the developed world clean (the 10% solution). The developed world can be more effective by improving its energy efficiency by 50%, in the near future. This has to be done by appropriate technologies, consistent with sound business plans, and market based economy. This presentation offers the engineering and economic foundations of the above proposition. Case studies and example technologies from the author’s group at Texas A&M University will be presented as specific illustrations.

Distributed Energy Storage for Wind Farms

This talk introduces the technology of transgenerator for distributed kinetic energy storage in wind farms. The transgenerator is a dual mechanical port (DMP) machine with two rotating members. This generator allows a flywheel to be connected to the generator directly and efficiently, enabling kinetic energy transfer between a wind turbine and a flywheel. This design also makes the system more compact. Further, this technology makes energy storage distributed, which increases the system overall reliability and stability.

On the Lifetime Emissions of Conventional, Hybrid and Electric Vehicles

Electric vehicles (EVs) are believed to be a good alternative to conventional internal combustion engine vehicles (ICEVs) to eliminate tailpipe CO2 emissions. However, they usually have considerably higher initial manufacturing pollution than IC engine vehicles, which will lead to a significant increase in their lifetime CO2 emissions. Hybrid electric vehicles (HEVs) are traditionally considered to have CO2 emissions between EVs and ICEVs. Previous research on emission comparisons among these vehicle types were confined to individual countries or regions. This paper makes worldwide evaluations of lifetime CO2 emissions of the 2020 Chevrolet Bolt EV, an example commercially available EV, and compares it globally with an ICEV and two types of HEVs. All the vehicles have at least the same vehicle performance as the Chevrolet Bolt EV. The results show that HEVs with dynamic programming optimization can have less worldwide lifetime emissions than both comparable EVs and IC engine vehicles without the sacrifice of vehicle performance.