Sunshine to petrol: Solar thermochemistry for liquid fuels

The goal of Sunshine to Petrol (S2P) is to directly and efficiently harness highly-concentrated thermal energy from the sun to energize CO₂ and H₂O into CO and H₂, i.e. synthesis gas, as a path to solar fuels. The heart of S2P is the CR5, a unique heat engine that employs a metal oxide-based thermochemical cycle to accomplish H₂O and CO₂ splitting. The continuous chemical and thermal cycling occurring in the CR5 poses numerous chemistry, materials, and engineering challenges. The basic operating principles of the CR5 design concept have recently been demonstrated in a first-of-its-kind prototype. These principles as well as progress towards improving and further demonstrating the prototype will be discussed. Additionally, advances in characterizing and understanding the remarkably dynamic behavior of the active materials will be presented. Systems and economic analyses and their implications for performance and technology needs will also be discussed.