Review of technology: Thermochemical energy storage for concentrated solar power plants

Abstract

To be able to extend the operation of a solar power plant (CSP) up to 15 hours, thermal energy storage (TES) is necessary. But TES also provides more versatility to the plant and makes its reliance during operation hours more dependable. On the other hand, due to the different CSP configurations, a broad spectrum of storage technologies, materials and methods are needed. Sensible and latent heat storage are known technologies in CSP, but thermochemical storage (TCS) is still very much at laboratory level. Nevertheless, TCS has de advantage of nearly no losses during storage and very good volumetric energy density. This review summarizes and compares the different TCS that are today being investigated. Those systems are based in three redox reactions, sulfur-based cycles, metal oxide reduction-oxidation cycles, and perovskitetype hydrogen production, and metal oxide non-redox cycles due to their similarity. This review shows that all these cycles are promising, but none of them seems to have all the characteristics necessary to become the only one storage system for CSP. The main conclusion of the review is that the calcium carbonate is the cycle with most experimentation behind it to infer that it could be viable and should thus be attempted at a research plant scale once a reactivation cycle can be designed; and the manganese oxide cycle, while less developed, is fundamental enough to be a suitable application for desert climates over the rest of the water-frugal or even water-avoiding cycles.

Thermische Energiespeicher – Trends, Entwicklungen und Herausforderungen

“…Nachdem der chemischen Speicherung thermischer Energie schon sehr lange ein sehr hohes Potenzial vorausgesagt wurde, zunächst allerdings kaum passende und sowohl technisch als auch wirtschaftlich umsetzbare Reaktionen in der Literatur beschrieben wurden, lassen die neueren Publikationen , hier auf eine beschleunigte Entwicklung und praktische Umsetzung erster Verfahren hoffen. Vor allem Reaktionen im mittleren und Hochtemperaturbereich für den Einsatz in solarthermischen Kraftwerken und in der chemischen und Prozessindustrie erscheinen chancenreich.…”

Stabilizing Particles of Manganese‐Iron Oxide with Additives for Thermochemical Energy Storage

“…However, the reaction enthalpy of the redox reaction is the main objective of thermochemical energy storage research. Thermochemical storage (TCS) systems are a promising way to increase the flexibility of concentrated solar power plants (CSP) or industrial processes operated at high temperature (700–1000 °C) . Especially weather instability and expandable operation time can be addressed with TCS systems to lower the cost of CSP and provide dispatchable power generation .…”

“…So far, solar receivers for the reduction of metal oxide particles by direct solar radiation apply rotary kiln,, gravity‐driven particle receivers, or packed bed reactors . A fluidized bed reactor and packed bed reactors, were investigated for reactors that are able to oxidize metal oxide particles and extract heat to a working fluid. A further development of the packed bed to a moving bed as a reactor concept for continuous heat extraction combines two main advantages.…”

“…Thermochemical storage (TCS) systems are a promising way to increase the flexibility of concentrated solar power plants (CSP) or industrial processes operated at high temperature (700-1000°C). [21][22][23][24][25][26] Especially weather instability and expandable operation time can be addressed with TCS systems to lower the cost of CSP and provide dispatchable power generation. [27] The reaction enthalpy of a chemical reversible gas-solid reaction stores heat in the endothermic reaction path and releases heat in the exothermic path.…”

Directly irradiated fluidized bed reactors for thermochemical processing and energy storage: Application to calcium looping

“…Integration of CSP with Thermal Energy Storage (TES) systems is crucial to overcome the inherent limitations associated with variable/seasonal availability and spatial non-uniformity of the source of solar energy. Among the different TES strategies, thermochemical conversion of solar energy owns unquestionable advantages such as an unlimited storage in time and space and larger storage densities, though the technology is more complex and still less developed [6][7][8][9]. In solar FB, the interaction between the incident radiative flux and the FB can occur in an indirect or direct way.…”