Stationary Battery Energy Storage Systems Analysis A focus on intraday shifting March 2023 Contents Preface 3 A note on the analysis 3 Commercialisation considerations Analysis 13 Summary 4 Recommendations 4 Definitions 5 Context 6 Examples of BESS projects and installations 7 Technologies and manufacturers 8 Lithium ion batteries 8 Redox flow batteries (RFB) 8 Molten salt batteries 9 Other metal batteries 9 Non-metal batteries 9 10 Technical comparison 13 Commercial comparison 17 Environmental comparison 19 Safety comparison 21 Conclusion and recommendations 22 Appendix 23 References 25 Preface A note on the analysis The purpose of this document is to provide a technical and commercial comparison of various battery energy storage system (BESS) chemistries which are currently available on the market suitable for intraday shifting. The analysis presented in this document was conducted internally by Ara Ake in Q4 2022, and as such, only shows a snapshot of the BESS market in time. Due to the significant growth and innovation occurring in the BESS market, depending upon when this document is picked up by the reader, the results throughout regarding the chemistries presented may be out of date. When such a BESS is combined with an intermittent renewable energy system with no inherent storage (wind, solar, run-of-the-river hydro), throughout the day, the resulting hybrid system can divert any excess energy produced at times of low demand to storage. The BESS can subsequently supply the grid at times of high demand, whilst also minimising the use of fossil fuels when attempting to match peak demand and overcome network constraints. 3 Summary Renewable energy is New Zealand’s largest source of electricity generation (82%) and provides approximately 41% of New Zealand’s primary energy supply.1 Of the installed renewable electricity capacity, 20% is associated with intermittent renewable energy systems (IRES) with little to no capacity for energy storage.2 • Nickel-hydrogen is designed for up to three charge/discharge cycles per day, yet is also capable of discharge rates varying between 2 and 12 hours. Competitors have similar charge/discharge rates, but are only designed for a maximum of one to two cycles per day before significantly impacting battery lifetime. There is potential to overcome this issue by combining IRES with stationary energy storage systems (i.e. batteries). With this kind of hybrid system, through intraday shifting, any excess energy produced by the plant at times of low demand may be stored to subsequently supply the grid at times of high demand, whilst also minimising the use of fossil fuels when attempting to match peak demand and overcome network constraints. • From a cost perspective, nickel-hydrogen is the best value for 12 hours or less of storage when comparing the levelised cost of storage (LCOS) of the technologies, a measure of the total cost of an energy storage system against the energy discharged over the battery’s lifetime. Ara Ake has identified a number of potential IRES power plants within New Zealand to demonstrate such a hybrid system. Lithium ion technology dominates the battery market across most sectors,3 including renewable energy storage, but it is of interest to Ara Ake to understand the technical and commercial characteristics of all the various battery solutions available on the market, as well as the safety and environmental impacts of these technologies. • The nickel-hydrogen technology has passed all relevant battery safety standards, including the UL 9540A test for thermal runaway. Many new battery technologies have passed this test, however, few lithium ion manufacturers have with only a single containerised lithium ion battery manufacturer in the UL 9540A database (EVLO). • On a footprint basis, nickel-hydrogen is competitive in terms of useable annual energy output with higher energy density lithium ion and molten salt battery chemistries. On a lifetime basis, nickel-hydrogen has among the highest energy output of all technologies studied, beating all manufacturers, but two lithium ion offerings (CATL and Tesla). Another battery technology which could be of interest is calcium-antimony (CaSb), given its high energy output and low LCOS similar to nickel-hydrogen. No environmental data for this technology was available, but all things considered, it could be an interesting technology for similar applicatio