This chapter has provided an overview of applications of concentrated solar radiation as a source of high-temperature process heat besides electricity generation. The pertinent scientific literature has been reviewed, with a focus on advances in solar process technology research and development. Technologies and applications have been divided broadly into three main groups, H₂/CO production, material processing and chemical commodity production, and other thermal processes.

Several processes have been described for the production of syngas (H₂ and CO) as a universal feedstock for the production of synthetic fuels. Concentrated solar energy can be used to produce syngas either via solar upgrading of carbonaceous feedstocks, such as coal, petcoke, methane, and biomass, or via thermochemical, electro-thermochemical, or carbothermal processes that split H₂O and CO₂. While processes involving fossil feedstocks are not CO₂-neutral, they do significantly reduce the CO₂ emissions involved with the use of fossil fuels and provide a viable transition path from today's fossil fuels to tomorrow's CO₂-neutral solar fuels produced from CO₂ and H₂O or other sustainable feedstocks. Two-step thermochemical cycles to split H₂O and CO₂ have been studied intensively in the literature as a long-term technology to produce CO₂-neutral synthetic fuels, due to their relative simplicity and their ability to reduce the temperatures required to dissociate H₂O and CO₂ compared to their direct thermolysis. Non-volatile metal oxides, including ferrites, ceria, and different perovskites, appear as promising oxygen exchange materials due to their ability to release oxygen and split H₂O/CO₂ without changing their solid phase, which simplifies the separation of the gaseous products. In addition, the electro-thermochemical hybrid sulfur cycle appears to be a promising technology to split H₂O, due to its strongly reduced electric energy demand compared to pure water electrolysis.

Concentrated solar energy can further be used in the production of a broad range of commodity materials. Calcination of limestone, the main energy-intensive process in the production of lime (quicklime) and cement, was demonstrated in a 10-kW solar-driven rotary kiln reactor with solar energy conversion efficiencies of up to 35%. The calcination/carbonation cycle with CaCO₃/CaO has further been shown to offer a method to remove CO₂ from flue gases or ambient air and to store solar energy thermochemically. Coproduction of CO and aluminum via the solar carbothermal reduction of aluminum oxide has been discussed as a cleaner alternative to the energy-intensive electrochemical route via the Hall–Héroult process. Other elements that can be produced via the solar carbothermal route include zinc, magnesium, and silicon, as well as hazardous elements, such as lead, chlorine, and cadmium extracted from waste materials. Solar carbothermal reduction of metal oxides can also be conducted to produce metal carbides and nitrides. These products can either be used as high-performance materials or as intermediates to produce fuels and commodity materials. For example, AlN has been used in a solar carbothermal two-step Al₂O₃/AlN cycle to produce ammonia from molecular nitrogen and water. Further, concentrated solar radiation can also be used as a source of high-flux radiation for processes requiring extreme heat fluxes, such as cutting, ablation, and heat treatment. Finally, there is a large potential to integrate solar process heat into low- to medium-temperature industrial processes across a range of industrial sectors, and for domestic water and space heating and cooling.

The research results to date demonstrate the usefulness of concentrated solar radiation as a universal, high-quality heat source, capable of providing virtually unlimited renewable energy for the production of clean electricity as well as fuels and materials.