The viability of vehicle-to-grid operations from a battery technology and policy perspective

Significance 

Vehicle-to-grid can be described as the reciprocal power flow of electricity between a battery on an electric vehicle and a recipient, such as an electrical grid, low voltage microgrid or a building.  Vehicle-to-grid can be characterized as a “grid service”, which introduces the aspect of financial incentives to consumers by offering frequency regulation and energy storage facilities to the grid, demand shifting, and lower rates resulting from avoidance of peak tariffs during high demand.  In addition, vehicle-to-grid offers the possibility of incorporating more localized renewables as a percentage of the generation mix.  Irrespective of these incentives and benefits, the effect of vehicle-to-grid on the degradation of Lithium-ion batteries is still a major concern.

A previous experiment on the effect of vehicle-to-grid operation on Li-ion battery degradation indicated that additional cycling to discharge electric vehicle batteries to the power grid, even at constant power, poses damaging effects on the performance of the battery. Another contradictory experiment presented data and simulation suggesting that vehicle-to-grid could extend the life of lithium-ion batteries in electric vehicles. The contradicting conclusions of the two studies are peculiar considering that both studies used similar 18650-type cells.

The findings of these two papers have drawn considerable attention. Therefore, Kotub Uddin at The University of Warwick in the United Kingdom in collaboration with Matthieu Dubarry and Mark Glick at University of Hawaii at Manoa in the USA reconciled their findings in this study summarizing that lithium-ion battery degradation governs the economic viability of vehicle-to-grid. The authors highlighted the policy, regulatory, and economic implications of managing battery degradation from vehicle-to-grid based primarily on the need for new smart facilities and an urgency for business models that account for battery degradation. Their research is published in the peer-reviewed journal, Energy Policy.

In the simplistic approach implemented by current vehicle-to-grid pilot studies in which an electric vehicle is discharged and charged without a consideration to battery degradation, the authors found vehicle-to-grid to not be economically viable owing to the effect additional cycling poses on battery longevity.  A smart control algorithm with the purpose of maximizing battery life can be used to reverse these effects.

In such an arrangement, the control algorithm would allow access to the stored energy only if there are no damaging effects on battery’s life, thus, the worst case would be that the battery would degrade as if there was no vehicle-to-grid application. This approach however depends on the development of precise battery prognostic models as well as further advances in trying to understand the causes, mechanisms, and the effects of battery degradation.

In view of the policy, the expected electric vehicle growth will offer huge potential for vehicle-to-grid to play a critical role as a grid service. Vehicle-to-grid in conjunction with jurisdictions committed to renewable energy, will be an enabler for carbon reduction. Setting up the grid improvements and platform would be an important first step. However, setting up a suitable compensation model will be challenging and important for vehicle-to-grid to grow. Finally, having a new, free market to aggregate and trade grid services will result in unbridled expansion of vehicle-to-grid as a future smart grid service.

vehicle-to-grid operations from a battery technology-Advances in Engineering

About the author

Dr. Kotub Uddin, Senior Research Fellow, WMG, University of Warwick

Dr Uddin completed a PhD in Applied Mathematics and Theoretical Physics in 2009. Since the completion of his PhD, he has been working on low carbon technologies for the transport and power sectors. His research specializes in the application of energy storage technologies for low carbon transport and power-grid decarbonization and ranges from mathematical modelling and fundamental science to systems engineering and experimental validation.

In his eight-year career he has developed deep insights of low carbon energy storage systems, of the technologies themselves, the techno-economics of such systems and their policy implications. Currently, Dr. Uddin is a Senior Research Fellow in Technologies for Sustainable Energy and the Environment at WMG, The University of Warwick. Previously he held positions of Senior Research Fellow within WMG (2012-2015) and Visiting Research Fellow at the Department of Mechanical Engineering, Imperial College (2013-2016).

In industry, he has worked on a number of electrification programs as a Senior Research Engineer at Jaguar Land Rover (2009-2012) and, prior to his return to WMG, he was a Principal Technical Consultant in alternative fuels at Ricardo Energy and Environment (2015-2016).

About the author

Matthieu Dubarry (PhD, Electrochemistry & Solid State Science, University of Nantes), has over 15 years of experience in renewable energy, with an emphasis in the area of lithium ion batteries. Following his PhD on the synthesis and characterization of materials for lithium batteries, Dr. Dubarry joined the Hawaii Natural Energy Institute at the University of Hawaii at Mānoa as a post-doctoral fellow in 2005 to work on the analysis of the usage of a fleet of electric vehicles. He was later appointed a faculty position in 2010 with a focus on battery testing, modeling and simulation.

While working for HNEI, Dr. Dubarry pioneered the use of new techniques for the analysis of the degradation of Li-ion cells and developed numerous software tools facilitating the prognosis of Li-ion battery degradation both at the single cell and the battery pack level. Current projects include the evaluation of grid scale Li-ion battery energy storage systems; the evaluation of the impact of vehicle-to-grid strategies on electric vehicle battery pack degradation; and the testing of emerging battery technologies for grid-connected and transportation applications.

About the author

Mark Glick is a Specialist and faculty member of the Hawaii Natural Energy Institute, overseeing energy policy and innovation. Glick previously served five years as Administrator of the Hawaii State Energy Office where he led Hawaii’s internationally regarded clean energy transformation efforts. He also served as Vice Chair of the National Association of State Energy Officials (NASEO).

Selected highlights of his tenure as Hawaii’s Energy Administrator include exceeding Hawaii’s 2015 interim renewable portfolio and energy efficiency portfolio standards and contributing to passage of the nation’s first 100 percent renewable portfolio standard and interim goal of 30 percent RPS by 2020. In each of Glick’s five years as Energy Administrator, Hawaii led the nation for five consecutive years in the per capita value of energy savings performance contracts. Glick was also responsible for all energy related regulatory filings and legislative testimony of the Department of Business, Economic Development and Tourism.

Glick served as senior advisor to the Texas Land Commissioner from 1987 to 1991, during which time he played a decisive role in passage of amendments to the Texas Clean Air Act and similar provisions in the federal Clean Air Act Amendments of 1990. For the next decade, Glick was a successful small business owner focused on reducing urban air pollution in the U.S. and abroad in collaboration with the U.S. Department of Energy, the Gas Research Institute, Petrobangla, Southern California Gas Company, Pacific Gas & Electric, Transco, Southern Union Gas Company and the New York City Department of Transportation among others. Returning to the public sector in 2003, Glick headed operations and economic development for the Office of Hawaiian Affairs from 2003 to 2010.

Glick serves on the Board of Directors of the Washington Place Foundation and previously served three terms as Executive Committee Chair of the Hawaii Chapter of the Sierra Club and as Vice Chair of the Hawaii Green Infrastructure Authority. Glick has a Master of Science, Public Management & Policy from Carnegie-Mellon University and a Bachelor of Arts in Mathematics from Lamar University.

Reference

Kotub Uddin, Matthieu Dubarry, and Mark B. Glick. The viability of vehicle-to-grid operations from a battery technology and policy perspective. Energy Policy, volume 113 (2018), pages 342–347.

 

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