Table of Content

1. Executive summary and conclusions
1.1 Purpose and scope of this report
1.2 Methodology of this analysis
1.3 Definition and need
1.4 The very different needs for grid vs beyond-grid LDES 2024-2044
1.5 Basic technology choices for LDES
1.6 Duration being achieved by technology and location
1.7 Lesson from relative investment by technology and location
1.8 Key conclusions: markets
1.9 Key conclusions: technology
1.10 Probable winner for beyond grid LDES: RFB success and gaps in its markets
1.11 Long Duration Energy Storage LDES roadmap 2023-2044
1.12 Market forecasts 2024-2044 in 35 lines
1.12.1 Total LDES market 8 hours and above in 11 technology categories $ billion 2023-2044 table, graphs
1.12.2 Regional share of LDES value market in four regions 2024-2044
1.12.3 Global market split by duration 2024 and 2044
1.12.4 Possible LDES global scenario TWh cumulative 2024-2044
1.12.5 Possible LDES global scenario average duration 2024-2044
1.12.6 Possible LDES global scenario TW cumulative 2024-2044
1.12.7 Beyond-grid LDES market in 8 categories $ billion 2023-2044: table and line graphs
1.12.8 RFB global value market grid vs beyond-grid 2023-2044 table, graph, explanation
1.12.9 RFB global value market short term and LDES 2023-2044 table, graph, explanation
1.12.10 Vanadium vs iron vs other RFB market % 2024-2044 table, graph, explanation
1.12.11 Regular vs hybrid RFB % value sales 2024-2044

2. Introduction
2.1 Overview: energy storage and its mitigation
2.1.1 What is energy storage?
2.1.2 Why stationary electricity storage will overtake mobile storage
2.1.3 Long Duration Energy Storage definition, need for new technology and alternatives
2.1.4 Capacity factor of wind, solar and options that need little or no LDES
2.1.5 Anatomy of LDES and why it is still needed
2.2 Going electric and the place of hydrogen and nine harvesting options
2.3 The solar megatrend
2.4 Growth of wind and solar energy sources across the world
2.5 The beyond-grid megatrend
2.6 Overview, definition and usefulness of Levelised Cost of Storage LCOS
2.7 Many different time parameters for storage
2.8 Progress to advanced photovoltaics and storage implications
2.8.1 Progress so far
2.8.2 Advanced photovoltaics
2.9 Advanced wind power to reduce need for LDES
2.9.1 Taller turbines
2.9.2 Airborne Wind Energy AWE vs ocean power to reduce need for LDES
2.10 Conventional hydropower

3. LDES design principles, parameter comparisons, trends and materials
3.1 Overview: definition, different design requirements for grid vs beyond-grid LDES
3.2 The 12 LDES technology choices compared in 7 columns
3.3 Nine primary LDES technology families, vs 17 other criteria
3.4 Progress competing for increasing LDES duration by technology
3.5 Equivalent efficiency vs storage hours for RFB and other options
3.6 Available sites vs space-efficiency for LDES technologies
3.7 LCOS $/kWh trend vs storage and discharge time
3.8 LDES power GW trend vs storage and discharge time
3.9 Days storage vs rated power return MW for LDES technologies
3.10 Days storage vs capacity MWh for LDES technologies
3.11 Potential by technology to supply LDES at peak power after various delays
3.12 Added value metals, compounds and membranes for LDES
3.12.1 Overview
3.12.2 Membrane difficulty levels and materials used and proposed
3.12.3 RFB membrane difficulty levels and materials used and proposed

4. Batteries for LDES: Redox flow batteries RFB
4.1 Overview
4.2 RFB technologies
4.2.1 Regular or hybrid and their chemistries with two SWOT appraisals
4.2.2 Specific designs by material: vanadium, iron and variants, other metal ligand, HBr, organic, manganese
4.3 SWOT appraisal of RFB for stationary storage
4.4 SWOT appraisal of RFB energy storage for LDES
4.5 Parameter appraisal of RFB for LDES
4.6 56 RFB companies compared in 8 columns: name, brand, technology, tech. readiness, beyond grid focus, LDES focus, comment
4.7 Profiles of 48 RFB manufacturers and putative manufacturers
4.8 Research analysis

5. Batteries for LDES: Advanced conventional construction batteries ACCB
5.1 Overview
5.2 SWOT appraisal of ACCB for LDES
5.3 Parameter appraisal of ACCB for LDES
5.4 Seven ACCB manufacturers compared: 8 columns: name, brand, technology, tech. readiness, beyond-grid focus, LDES focus, comment
5.5 Iron-air: Form Energy USA with SWOT appraisal
5.6 Molten calcium antimony: Ambri USA with SWOT appraisal
5.7 Nickel hydrogen: EnerVenue USA with SWOT
5.8 Sodium-ion many companies but limited beyond-grid LDES potential
5.9 Sodium sulfur: NGK/ BASF Japan/ Germany and others with SWOT
5.10 Zinc-air: eZinc Canada with SWOT
5.11 Zinc halide EOS Energy Enterprises USA with SWOT

6. Compressed air CAES for LDES
6.1 Overview
6.2 Undersupply attracts clones
6.3 Market positioning of CAES
6.4 Parameter appraisal of CAES vs LAES
6.5 CAES technology options
6.5.1 Thermodynamic
6.4.2 Isochoric or isobaric storage
6.4.3 Adiabatic choice of cooling
6.6 CAES manufacturers, projects, research
6.6.1 Overview
6.6.2 Siemens Energy Germany
6.6.3 MAN Energy Solutions Germany
6.6.4 Increasing the CAES storage time and discharge duration
6.6.5 Research in UK and European Union
6.7 CAES profiles and appraisal of system designers and suppliers
6.7.1 ALCAES Switzerland
6.7.2 APEX CAES USA
6.7.3 Augwind Energy Israel
6.7.4 Cheesecake Energy UK
6.7.5 Corre Energy Netherlands
6.7.6 Gaelectric failure Ireland – lessons
6.7.7 Huaneng Group China
6.7.8 Hydrostor Canada
6.7.9 LiGE Pty South Africa
6.7.10 Storelectric UK
6.7.11 Terrastor Energy Corporation USA
6.8 SWOT appraisal of CAES for LDES

7. Chemical intermediary hydrogen, ammonia, methane LDES
7.1 Overview
7.2 Hydrogen compared to methane and ammonia for LDES
7.3 Beware vested interests
7.4 The hydrogen economy vs electricity
7.5 Sweet spot for chemical intermediary LDES
7.6 Calculating success based on dubious assumptions
7.7 Mining giants prudently back many options
7.8 For buildings, all options together would be too expensive
7.9 Technologies for hydrogen storage
7.9.1 Overview
7.9.2 Choices of underground storage for hydrogen
7.9.3 Hydrogen interconnectors for electrical energy transmission and storage
7.9.4 Review of 15 projects that use hydrogen for energy storage in a power system
7.10 Parameter appraisal of hydrogen storage for LDES
7.11 SWOT appraisal of hydrogen, methane, ammonia for LDES

8. Liquefied gas for LDES– air LAES or carbon dioxide
8.1 Overview
8.2 Principle of liquid air energy storage system
8.3 Higher energy density but often higher LCOS than CAES
8.4 Hybrid LAES
8.5 Parameter appraisal of LAES for LDES
8.6 Increasing the LAES storage time and discharge duration
8.7 Highview Power UK with Zhar research appraisal
8.8 Highview Power and partners in Australia, Spain, Chile, Australia
8.9 Phelas Germany
8.10 LAES research: Mitsubishi, Hitachi, Linde, European Union, Others
8.11 SWOT appraisal of LAES for LDES
8.12 Liquid carbon dioxide energy storage: Energy Dome Italy
8.12.1 Overview and process
8.12.2 SWOT appraisal of Energy Dome liquid carbon dioxide LDES.

9. Pumped hydro: conventional PHES and advanced APHES
9.1 Conventional pumped hydro PHES
9.1.1 Overview: capability and available sites
9.1.2 Three basic technologies
9.1.3 Projects and intentions across the world
9.1.4 Economics
9.1.5 Parameter appraisal
9.1.6 SWOT appraisal of PHES
9.2 Advanced pumped hydro APHES does not need mountains
9.2.1 Overview
9.2.2 Pressurised underground: Quidnet Energy USA
9.2.3 Sea floor StEnSea and Ocean Grazer compared to other underwater LDES
9.2.4 Brine in salt caverns Cavern Energy USA
9.2.5 Mine storage Sweden
9.2.6 Heavy water up hills RheEnergise UK
9.2.7 SWOT appraisal of APHES

10. Solid gravity energy storage SGES
10.1 Overview
10.2 Parameter appraisal of SGES for LDES
10.3 ARES USA
10.4 Energy Vault Switzerland
10.5 Gravitricity UK
10.6 SinkFloat Solutions France

11. Thermal energy storage for delayed electricity ETES
11.1 Overview
11.2 Parameter appraisal of ETES for LDES
11.3 Special case: molten salt storage for concentrated solar
10.4 Lessons from failure of Azelio Sweden, Siemens Gamesa Germany and Stiesdal Denmark
11.5 Antora USA
11.6 Malta Inc Germany
11.7 SWOT appraisal of ETES for LDES