# Thermochemical storage: What to track

An R&D bet: cycle stability and the first real orders

Source page: https://www.materialinsights.org/energy/e_thermochem_store/tracking/

What this tab covers The attributes worth tracking regularly, with the latest value, the direction of travel and why each matters.

Treat as an R&D bet: track cycle stability, pilot results and whether any firm reaches commercial orders.

| Category | Attribute | Latest | Trend | Why it matters |
|---|---|---|---|---|
| Techno-economic | **LCOS trajectory (capex outlook)** | No LCOS found; oxide storage estimated USD 15-100 per kWh; IRENA expects as low as USD 10 by 2050^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2020/Nov/IRENA_Innovation_Outlook_TES_2020.pdf)^[5](https://www.energy.gov/eere/solar/articles/lessons-learned-devolping-thermochemical-cycles-solar-heat-storage-applications) | ↗ improving | Long-dated target with high uncertainty. |
| Technical | **Capacity fade and state of health (cycle stability)** | CaO residual conversion 7.5% (model assumption); Ti-doped Mn2O3 loses 53-63% of uptake in 30 cycles^[4](https://zaguan.unizar.es/record/120012/files/texto_completo.pdf)^[6](https://pubs.rsc.org/en/content/articlehtml/2021/ra/d1ra05472d) | ↗ improving | Sintering is the main barrier; dopants and stabilisers are the fix being tested. |
| Supply chain | **Critical mineral cost and geopolitical concentration** | Mostly abundant materials; cobalt oxide is the exception^[5](https://www.energy.gov/eere/solar/articles/lessons-learned-devolping-thermochemical-cycles-solar-heat-storage-applications) | → stable | Choice of oxide sets mineral exposure. |
| Market | **Ancillary service market saturation** | Not relevant; slow response suits seasonal heat^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2020/Nov/IRENA_Innovation_Outlook_TES_2020.pdf) | → stable | Value lies in long-duration heat. |
| Regulatory | **Safety and environmental compliance** | Process and pressure rules; some salts release HCl^[3](https://pure.tue.nl/ws/portalfiles/portal/65069212/1_s2.0_S0306261917304750_main.pdf) | → stable | No dedicated standards yet. |
| Impact | **Lifecycle carbon payback period** | Energy payback 2.2-2.5 years for a calcium looping solar plant^[9](https://doi.org/10.1016/j.enconman.2022.115428) | → stable | Shows the embodied footprint is small. |
| Technical | **Pilot scale reached** | CREATE 182 kWh (Warsaw); SaltX 0.5 MW / 10 MWh (Berlin)^[2](https://www.mdpi.com/1996-1073/15/2/647)^[7](https://iea-shc.org/article?NewsID=304) | ↗ improving | First proof points outside the laboratory. |
| Technical | **Technology readiness** | Mostly prototype (IRENA 2020); salt hydration expected to advance in 5-10 years^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2020/Nov/IRENA_Innovation_Outlook_TES_2020.pdf) | ↗ improving | Indicates investment horizon. |

#### Sources

1. [Innovation Outlook: Thermal Energy Storage](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2020/Nov/IRENA_Innovation_Outlook_TES_2020.pdf) IRENA, 2020
2. [Review of Carnot Battery Technology Commercial Development (Novotny et al., Energies 15(2), 647)](https://www.mdpi.com/1996-1073/15/2/647) MDPI, 2022
3. [A review of salt hydrates for seasonal heat storage in domestic applications (Donkers et al., Applied Energy 199, 45-68)](https://pure.tue.nl/ws/portalfiles/portal/65069212/1_s2.0_S0306261917304750_main.pdf) Eindhoven University of Technology repository, 2017
4. [Operation maps in calcium looping thermochemical energy storage for concentrating solar power plants (Pascual, Lisbona and Romeo, Journal of Energy Storage 55, 105771)](https://zaguan.unizar.es/record/120012/files/texto_completo.pdf) University of Zaragoza repository, 2022
5. [Lessons Learned: Developing Thermochemical Cycles for Solar Heat Storage Applications (Wong, General Atomics; conference slides, DOE Workshop on TES for CSP, January 2013)](https://www.energy.gov/eere/solar/articles/lessons-learned-devolping-thermochemical-cycles-solar-heat-storage-applications) US Department of Energy, 2013
6. [Effects of TiO2 doping on the performance of thermochemical energy storage based on Mn2O3/Mn3O4 redox materials (Wang, Wang, Dou, Ma and Liang, RSC Advances 2021)](https://pubs.rsc.org/en/content/articlehtml/2021/ra/d1ra05472d) Royal Society of Chemistry, 2021
7. [Compact thermochemical heat storage prototype (CREATE project, IEA SHC Task 58)](https://iea-shc.org/article?NewsID=304) IEA Solar Heating and Cooling Programme, 2020
8. [Life cycle and environmental assessment of calcium looping (CaL) in solar thermochemical energy storage (Colelli et al., Energy Conversion and Management 257, 115428)](https://doi.org/10.1016/j.enconman.2022.115428) Elsevier, 2022

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_thermochem_store/index.md)
- [Overview](https://www.materialinsights.org/energy/e_thermochem_store/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_thermochem_store/correlation/index.md)
- [Science and technology](https://www.materialinsights.org/energy/e_thermochem_store/sg-sci/index.md)
- [Engineering and performance](https://www.materialinsights.org/energy/e_thermochem_store/sg-eng/index.md)
- [Economics](https://www.materialinsights.org/energy/e_thermochem_store/sg-econ/index.md)
- [Impact and additionality](https://www.materialinsights.org/energy/e_thermochem_store/sg-impact/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_thermochem_store/links/index.md)