Techno-Economic Analysis of Candidate Oxide Materials for Thermochemical Storage in Concentrating Solar Power Systems

Abstract

The thermal storage capability is an important asset of state-of-the-art concentrating solarpower plants. The use of thermochemical materials, such as redox oxides, for hybridsensible/thermochemical storage in solar power plants offers the potential for higherspecific volume and mass storage capacity and as a consequence reduced levelized costof electricity making such plants more competitive. For the techno-economic systemanalysis, three candidate redox materials were analyzed for their cost reduction potential:cobalt-based, manganese–iron–based, and perovskite-based oxide materials. As areference process the use of inert commercial bauxite particles (sensible-only storage)was considered. A solar thermal power plant with a nominal power of 125 MWeand astorage capacity of 12 h was assumed for the analysis. For each storage material a plantlayout was made, taking the specific thermophysical properties of the material intoaccount. Based on this layout a particle break-even cost for the specific material wasdetermined, at which levelized cost of electricity parity is achieved with the referencesystem. Cost factors mainly influenced by the material selection are storage cost andsteam generator cost. The particle transport system cost has only a minor impact. Theresults show differences in the characteristics of the materials, for example, regarding theimpact on storage size and cost and the steam generator cost. Regarding the economicpotential of the candidate redox materials, the perovskite-based particles promise to haveadvantages, as they might be produced from inexpensive raw materials.