By Gregory Keoleian, Ph.D.
Electric Vehicles (EVs), coupled with the clean energy transition, hold the promise of greening mobility and achieving a zero-emissions vehicle future in the binational Great Lakes region, the home for the global automotive industry, representing a significant economic and environmental opportunity for the region and an important response to the ambitious climate change and sustainability priorities outlined in the new Roadmap for a Renewed U.S.-Canada Partnership. However, there are major policy, infrastructure, and supply chain implications that must be considered on a regional, cross-border basis, including the responsible sourcing, manufacturing, use, and recycling of next generation batteries that are critical for the operation of EVs. Dr. Keoleian joined three experts in a dialogue on that subject April 29. His research, summarized below, informed that conversation.
The transportation sector is responsible for 29% of US greenhouse gas emissions (GHGs) and electric vehicles (EVs) are the path forward for the auto industry to decarbonize mobility. Although current EV sales are only about 2% of the market, manufacturers are gearing up to launch a wide selection of EV models ranging from sporty sedans to full-size pick-up trucks.
EVs provide an enormous opportunity to lessen the environmental footprint of mobility, but only if we account for how they are produced, driven, charged, and managed when these vehicles are retired. Battery technology and management is at the core in answering these questions and is critical to optimize to fully benefit from this rapidly emerging shift in mobility.
In our paper, “Green Principles for Responsible Battery Management in Mobile Applications,” we outlined the opportunities for reducing GHGs from the transportation sector. Batteries are the central component of energy storage systems for EVs, and their integration into EVs can lead to a wide range of possible environmental outcomes depending on factors such as battery materials, electricity source, charging patterns, and battery recycling and recovery infrastructure.
Given the complexities of battery systems, we developed a framework to systematically evaluate environmental impacts across battery system life cycle stages, from material extraction and production to use in the EV, through the battery’s end-of-life. We developed a set of ten principles to provide practical guidance, metrics, and methods to accelerate environmental improvement of mobile battery applications and foster innovation by designers, suppliers, original equipment manufacturers (OEMs), and end-of-life managers. The goal of these principles, which should be implemented together as a set, is to enhance stewardship and sustainable life cycle management by guiding design, material choice, deployment (including operation and maintenance), and infrastructure planning of battery systems in mobile applications. These principles are applicable to emerging battery technologies (e.g., lithium-ion), and can also enhance the stewardship of existing (e.g., lead-acid) batteries.
- Principle #1: Choose battery chemistry to minimize life cycle environmental impact.
Develop and select battery chemistry that enhances operational and broader life cycle performance, which ultimately drive sustainability.
- Principle #2: Minimize production burden per energy service.
Minimize the production burden per energy service provided by the battery system. Production burden includes material production, manufacturing, and associated infrastructure.
- Principle #3: Minimize consumptive use of critical and scarce materials.
Design and production of batteries should minimize the consumptive use of scarce and critical materials, since depletion of materials can constrain continued deployment of these systems. It is essential that increased adoption of EVs does not cause adverse consequences, such as unsustainable consumption of metals (lithium, cobalt, manganese) in addition to energy-intensive or high-impact steps in battery production.
- Principle #4: Maximize battery round-trip efficiency.
Maximize battery round-trip efficiency to minimize energy losses during vehicle charging and operation.
- Principle #5: Maximize battery energy density to reduce vehicle operational energy.
Design battery storage with maximum energy density to minimize mass-related fuel consumption. Reducing vehicle mass is a key strategy to achieve significant reductions in life cycle energy consumption and emissions.
- Principle #6: Design and operate battery systems to maximize service life and limit degradation. Use charging patterns that minimize degradation by preserving battery capacity and round-trip efficiency. Temperature also impacts degradation.
- Principle #7: Minimize hazardous material exposure, emissions and ensure safety. Exposure to, and emission of, hazardous materials should be minimized during production, use (operation and service), and end-of-life stages of the battery system to provide a safe environment for communities, workers, and users.
- Principle #8: Market, deploy, and charge electric vehicles in cleaner grids. Charge EVs with cleaner electricity to lower life cycle emissions. Any grid-vehicle interaction should result in lower emissions and cause minimum battery degradation.
- Principle #9: Choose powertrain and vehicle types to maximize life cycle environmental benefits. Increasing degree of electrification from ICEV to PHEV to BEV should result in lower life cycle emissions, depending on the grid mix.
- Principle #10: Design for end-of-life and material recovery. “Circular economy” end-of-life approaches (reuse, remanufacturing, and recycling) can significantly reduce environmental impacts and global demand for extracted materials.
The Center for Sustainable Systems (CSS) has also developed a complementary set of green principles on energy storage for electricity grid applications. As indicated in Principle 8 above, decarbonization of the grid is critical to lowering the carbon footprint of EVs. Energy storage will be critical in managing the variability in electricity generation from renewable sources. Renewable sources currently account for 20% of the US average fuel mix but utilities are accelerating the deployment of wind and solar electricity generation facilities while simultaneously decommissioning plants that combust fossil fuel.
About the Author
He has appointments as Professor in the School for Environment and Sustainability and as Professor in the Department of Civil and Environmental Engineering. He earned his PhD in Chemical Engineering from the University of Michigan in 1987.
His research focuses on the development and application of life cycle models and sustainability metrics to guide the design and improvement of products and technology. Through his interdisciplinary research, he has analyzed diverse systems including conventional and alternative vehicle technology, renewable energy technologies, buildings and infrastructure, consumer products and packaging, and a variety of food systems.
He helped launch the Engineering Sustainable Systems dual degree program between the School for Environment and Sustainability and the College of Engineering to train a new breed of engineers in sustainable systems. He teaches interdisciplinary graduate courses on sustainable energy systems and industrial ecology. He served a two year term as the President of the International Society for Industrial Ecology from 2011-2012. Dr. Keoleian was recently named to the Reuters Hot List of the world’s top climate scientists.
About the Publication
“Green principles for responsible battery management in mobile applications,” was authored by Maryam Arbabzadeh Geoffrey M.Lewisand Gregory A.Keoleian; Center for Sustainable Systems, School for Environment & Sustainability, University of Michigan, 440 Church St., Ann Arbor, MI, 48109, United States, and published in the Journal of Energy Storage Volume 24, August 2019, 100779. For more information, see abstract.
The principles were developed under sponsorship from the national nonprofit Responsible Battery Coalition (RBC). The principles represent a comprehensive set of recommendations to guide mobile battery deployment and technological development from an environmental perspective. The RBC also sponsored CSS research focusing on Principle #6 in a related publication.