Integrated solar thermochemical cycles comprise a range of promising novel process technologies that use concentrated solar energy to drive endothermic chemical reactions at elevated temperatures. The most promising application is the production of carbon-neutral fuels, particularly via single or multistep water and CO 2 splitting or via the solar thermochemical upgrading of carbonaceous fuels such as biomass, waste, or oil residues. Furthermore, intermediate storage of solar energy in reversible reactions, the so-called solar thermochemical heat pipes, shows great promise to replace latent heat storage for concentrating solar power generation. Potential niche applications are material processing and material testing. Widespread deployment of solar thermochemical cycles hinges on the development of several key technologies: (i) reaction systems and catalysts able to endure tens of thousands of conversion cycles without significant degradation, (ii) reactors and heat recuperation systems that fully exploit the theoretical potential of solar thermochemical cycles, (iii) industrial-scale reactor technologies, and (iv) process control technologies that address the inherently transient nature of solar power. C 2012 John Wiley & Sons, Ltd.