Material Insights · Understanding the Material World

Thermochemical storage: Economics

Cheap ingredients, expensive reactors, early estimates

What this tab covers Economics and financial structure: capital versus operating cost, levelised cost of storage, and how the asset earns money.

Cost data are early estimates. Material costs can be very low, but reactors dominate, and IRENA sees costs near USD 10 per kWh only by 2050.

Capex versus opex

Unfavourable

Early US estimates put manganese-iron oxide storage at USD 15 to 35 per kWh and cobalt-aluminium oxide at USD 50 to 100, against a USD 15 target. IRENA expects thermochemical systems to enter demonstration at prices as low as USD 10 per kWh by 2050, compared with today's molten salt at USD 26.1 to 40. Replacing degraded sorbent, such as limestone in calcium looping, would be a recurring cost.15

Oxide storage cost estimates (2013) Mn-Fe USD 15-35; Co-Al USD 50-100 per kWh5 IRENA outlook, 2050 as low as USD 10 per kWh1 Molten salt comparator (2020) USD 26.1-40 per kWh1

Levelised cost of storage

Unfavourable

No levelised cost of storage for thermochemical systems alone was found. Published system figures are for whole solar plants: early modelling put solar power with oxide storage at USD 0.09 to 0.17 per kWh (2010 costs), and a solar thermal, solar PV and calcium looping hybrid at USD 123 per MWh (an earlier study cited in a 2022 review).45

CSP with oxide storage, modelled (2010 costs) USD 0.09-0.17 per kWh5 CSP plus PV plus calcium looping hybrid USD 123 per MWh4

Revenue stack and market participation

Mixed

Intended revenue is the same as other heat stores: buying cheap electricity or surplus solar heat and selling heat later, ideally across seasons, where few alternatives exist. Calcium looping is mainly aimed at solar thermal power plants. Grid service revenue is unlikely because conversion is slow.14

Sources

  1. Innovation Outlook: Thermal Energy Storage IRENA, 2020
  2. Operation maps in calcium looping thermochemical energy storage for concentrating solar power plants (Pascual, Lisbona and Romeo, Journal of Energy Storage 55, 105771) University of Zaragoza repository, 2022
  3. Lessons Learned: Developing Thermochemical Cycles for Solar Heat Storage Applications (Wong, General Atomics; conference slides, DOE Workshop on TES for CSP, January 2013) US Department of Energy, 2013