Sustainable Aviation Fuels are designed to replace or supplement conventional fossil-based aviation fuels, reducing greenhouse gas emissions and mitigating the environmental impact of air travel. They are produced from sustainable feedstocks such as biomass, waste oils, green hydrogen or from renewable energies. Solar thermal energy plays a crucial role in producing synthetic hydrocarbon fuels offering a pathway towards sustainable aviation fuel production.
Solar thermal energy can be used to produce hydrogen through a process called solar water splitting by heating water to very high temperatures (typically above 1500°C), causing it to split into hydrogen and oxygen through thermochemical reactions. While the technology is still in the research and development stage, advancements in materials, reactor design, and system integration are paving the way for scalable and cost-effective solar hydrogen production in the future.
Solar thermal energy can also be integrated in high-temperature electrolysis with elevated temperatures (typically above 700°C) to split water vapor into hydrogen and oxygen directly, bypassing the need for liquid water. This method can be more efficient than conventional electrolysis, especially when integrated with industrial processes that generate waste heat.
The produced hydrogen from each method can then be combined with carbon dioxide, captured from the atmosphere or industrial sources through different processes.
The produced hydrogen can be stored and used as a versatile and clean energy carrier. It can be utilized in fuel cells to generate electricity on-demand, powering vehicles or providing electricity in remote areas. Hydrogen can also be used as a feedstock in various industrial processes, such as the production of chemicals and fertilizers, further reducing carbon emissions.
Moreover, hydrogen produced via concentrated solar power is considered a green hydrogen source since it relies on renewable energy and does not generate greenhouse gas emissions during production. This aligns with the global efforts to mitigate climate change and transition towards a low-carbon economy.
This mixture of hydrogen and carbon dioxide can undergo various chemical reactions using concentrated solar thermal energy, to produce synthetic hydrocarbon fuels, including synthetic kerosene for aviation applications or synthetic diesel and gasoline.