Solar thermochemical fuels: research and development in the United States (特集 太陽熱発電・太陽熱燃料製造の最先端(第2集)) Solar Thermochemical Fuels: Research and Development in the United States(<Special Article>Advances in Concentrated Solar Power (CSP) and Solar Thermochemistry: Part II)

The United States has a tremendous appetite for liquid fuels to supply the transportation sector and industry. Currently, most of these fuels are derived from imported petroleum. There is now an increasing awareness of the need to develop alternative pathways and feedstocks for producing transportation fuels domestically. One such pathway involves the use of concentrated solar energy to drive the conversion of chemical feedstocks such as carbon dioxide, water, and methane, into fuel products and intermediates such as hydrogen and carbon monoxide via a series of high temperature chemical reactions. These fuel products may be used directly or further converted into liquid fuels. By using solar energy at high temperature and avoiding energy inputs in the form of work and the associated conversion of thermal energy to other forms (i.e. electrochemical processes) it is conceptually possible to achieve relatively high energy efficiency. A review of current and past solar thermochemical fuel production (STC) projects in the United States is presented in this paper. The focus is on those processes that use either water or carbon dioxide as feedstocks. Processes using biomass and hydrocarbon feedstocks are not considered in depth in this report. There are currently no commercial STC projects in operation, so this review will focus primarily on federally funded efforts at the National Laboratories, universities, and in the private sector.