 This paper discusses the potential of a two-step solar thermal process to split water into hydrogen and oxygen, which can be used to create renewable liquid hydrocarbons. The process involves heating up zinc oxide with concentrated solar energy, followed by the use of hydrogen and carbon dioxide to produce hydrogen and carbon monoxide, respectively. The zinc oxide is then recycled back to the first step. The paper also outlines the scientific principles behind this process, as well as the technological advancements made in solar reactor engineering. Finally, it examines the environmental impacts and economics of the process. This article was authored by Aldo Steinfeld, Anton Meyer and Peter G. Lautzenheiser.