Page 77 - North American Clean Energy January/February 2019 Issue

Dr. Davion Hill is an energy storage expert managing DNV GL’s energy storage business for the Americas region. He is an Executive Board member for NAATBatt International, former President (2015) and Chairman
(2016), and also serves on the Board of Directors for NYBEST. As an energy storage expert serving the energy project development and energy nance communities, Dr. Hill has been principle investigator for R&D programs with ARPA-e, NYSERDA, the US Department of Transportation,
number of amp-hours or watt-hours a battery can discharge over its life. e throughput should be quanti ed subject to these conditions: 1) temperature, 2) average SOC, 3) SOC change per cycle
(or SOC swing), and 4) C-rate (an indirect measure of battery current). Battery performance ranked in these terms can be used to validate a warranty.
ere are two factors that must be addressed to estimate whether the warranty and/or capacity guarantee
is su cient. First, the system design comprises a number of battery cells con gured in series and parallel, to achieve the desired power and voltage of the system. is con guration will impact the current and SOC conditions for the battery cells. e battery management system (BMS) imposes static upper and lower SOC limits on the cells. ese limits should be compared against the SOC and C-rates that maximize the life
of the cell. It is for these reasons that
the electrochemical SOC at the cell
and the system SOC are two di erent numbers. If the warranty is o ered in
the context of system conditions, the cell-level implications will need to be back-calculated. Second, the control of the system—as it pertains to its use case and environmental conditions—will need to be analyzed to determine if the SOC, temperature, and power of the system are detrimental to the warranty.
e old legacy of a 10-year warranty with 80 percent remaining capacity fails to acknowledge condition-dependency on battery throughput. As projects are being deployed at the gigawatt scale, it is evidential that there are commercially viable and technically sound solutions in the marketplace. Unfortunately, due to lack of transparency in warranties and performance, their viability is not apparent to the greater market. e industry precedent of relying on the manufacturer’s self-validation of the warranty is exposing the industry to technical risk. Buyers and owners of energy storage systems can mitigate this risk by participating in independent testing programs to validate warranties and performance guarantees. is ultimately leads to more certainty in transactions, which increases investor con dence, and accelerates the market.
the Federal Aviation Administration, and the California Energy Commission, Dr. Hill also led DNV GL’s North American joint industry guidelines for energy storage on hybrid vessels in the oil & gas sector, and was one of several authors for DNV GL’s GRIDSTOR RP-0043. As primary author on the Consolidated Edison Battery Energy Storage Safety report, Dr. Hill led an industry-wide conversation
in 2016-2017 to address re safety issues in energy storage. Dr. Hill’s expertise spans energy storage business models and project development, safety issues and integration, and
long-term performance to support warranties. In 2011 Dr. Hill was a co-awardee of the TechColumbus Innovation award for DNV’s analysis of grid scale energy storage via CO2 conversion, and also chaired panels for the National Academy of Engineers on energy storage across scales. He is an accomplished author with over 30+ peer reviewed publications and articles. and acquired his PhD in applied materials physics from e Ohio State University in 2006.
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