Electricity Storage Technology Review Prepared for U.S. Department of Energy Office of Fossil Energy June 30, 2020 Executive Summary Contents Executive Summary ....................................................................................................................................... 1 Introduction .................................................................................................................................................. 1 Project Overview and Methodology ......................................................................................................... 1 Worldwide Electricity Storage Installations .............................................................................................. 2 The Issue at Hand: Large Market Penetration of Intermittent Electricity Generation Capacity ............. 4 Services Provided by Energy Storage Systems .......................................................................................... 5 Indirect Benefits: Grid-Connected Services Provided by Energy Storage ............................................. 5 Direct Benefits: Integrating Energy Storage Directly with Generation ................................................. 6 Opportunities for Fossil Thermal Integration with Storage .................................................................. 6 Technology Reviews ...................................................................................................................................... 8 Stationary Battery Energy Storage ............................................................................................................ 9 Lithium-Ion BES ..................................................................................................................................... 9 Redox Flow BES ................................................................................................................................... 14 Other BES ............................................................................................................................................ 19 Mechanical Energy Storage..................................................................................................................... 22 Compressed Air Energy Storage (CAES) .............................................................................................. 22 Pumped Storage Hydropower (PSH) ................................................................................................... 24 Thermal Energy Storage .......................................................................................................................... 27 Super Critical CO 2 Energy Storage (SC-CCES) ...................................................................................... 27 Molten Salt .......................................................................................................................................... 29 Liquid Air ............................................................................................................................................. 31 Chemical Energy Storage ........................................................................................................................ 33 Hydrogen ............................................................................................................................................. 34 Ammonia ............................................................................................................................................. 38 Methanol ............................................................................................................................................. 40 Conclusions and Recommendations ....................................................................................................... 43 Bibliography ................................................................................................................................................ 49 Electricity Storage Technology Review i Executive Summary Table of Figures Figure 1. Comparative Matrix with Preliminary Assessment of Energy Storage Technologies ................... 2 Figure 2. Worldwide Electricity Storage Operating Capacity by Technology and by Country, 2020 ........... 2 Figure 3. Worldwide Storage Capacity Additions, 2010 to 2020 ................................................................. 3 Figure 4. Illustrative Example of the Impact of PV Deployment on Generator Dispatch ............................ 4 Figure 5. Overview of Range of Services That Can Be Provided by Energy Storage Systems ...................... 5 Figure 6. Co-Locating Vs. Standalone Energy Storage at Fossil Thermal Powerplants Can Provide Net Benefits Depending on Ancillary Electric Market Structure ......................................................................... 7 Figure 7. Illustrative Configuration of a Stationary Lithium-Ion BES ........................................................... 9 Figure 8. Summary Operating Characteristics of Lithium-Ion BES .............................................................. 11 Figure 9. Example Lithium-Ion BES Cost Projections Illustrating Capacity and Energy Considerations, $/kW............................................................................................................................................................ 13 Figure 10. Evolution of Electric Vehicle BES Cost Projections Illustrate the Effects of Ongoing Technological Change, $/kWh .................................................................................................................... 13 Figure 11. Example Configuration of a Vanadium Redox-Flow BES ........................................................... 14 Figure 12. Summary Operating Characteristics of Flow BES ...................................................................... 15 Figure 13. Companies Active in Flow BES Commercialization Efforts........................................................ 16 Figure 14 Illustrative Cost Projections for Flow BES at Different Hour Ratings, $/kW .............................. 18 Figure 15. U.S. Large-Scale BES Power Capacity and Energy Capacity by Chemistry, 2003-2017 ............. 19 Figure 16. Illustrative Comparative Costs for Different BES Technologies by Major Component ............. 21 Figure 17. Diagram of A Compressed Air Energy Storage System ............................................................. 22 Figure 18. Diagram of A Pumped Storage Hydropower Station ................................................................ 24 Figure 19. Diagram of Super Critical CO2 Energy Storage System ............................................................. 27 Figure 20. Molten Salt Energy Storage Principle of Operation .................................................................. 29 Figure 21. Illustrative Integration of Thermal Energy Storage into Powerplant ........................................ 29 Figure 22. Liquid Air Power Cycle ............................................................................................................... 31 Figure 23. “Universal” Block Flow Diagram Illustrating a Multitude of Opportunities for Fossil Thermal Powerplant Systems to be Integrated with Chemical Energy Storage ....................................................... 33 Figure 24. Efficiencies of Fuel Cells at Different Chemistries and Temperatures ...................................... 35 Figure 25. Comparative Assessment of Energy Storage Technologies ...................................................... 43 Figure 26. Hourly Coal Powerplant Efficiency by Load Level for a Representative Region in 2013 - 2015 45 Figure 27. Fossil Thermal Powerplant Characteristics ............................................................................... 46 Figure 28. “Getting It Right” in Economic Unit Commitment and Dispatch is Key .................................... 47 Figure 29. Modeling Issues ......................................................................................................................... 48 Note about th e Review : The Review is intended to provide a briefing regarding a range of energy storage technologies that includes a detailed listing of primary sources. For that reason, Microsoft® Word, rather than PowerPoint, was used for producing the Review. Electricity Storage Technology Review ii Executive Summary Executive Summary • Objective: o The objective is to identify and describe the salient characteristics of a range of energy storage technologies that currently are, or could be, undergoing R&D that could directly or indirectly benefit fossil thermal energy power systems. o The uses for this work include: ° Inform DOE-FE of range of technologies and potential R&D. ° Perform initial steps for scoping the work required to analyze and model the benefits that could arise from energy storage R&D and deployment. • Technology Benefits: o There are potentially two major categories of benefits from energy storage technologies for fossil thermal energy power systems, direct and indirect. ° Grid-connected energy storage provides indirect benefits through regional load shaping, thereby improving wholesale power pricing, increasing fossil thermal generation and utilization, reducing cycling, and improving plant efficiency. ° Co-located energy storage has the potential to provide direct benefits arising from integrating that technology with one or more aspects of fossil thermal power systems to improve plant economics,