Review: An Economic Perspective on Liquid Solar Fuels

Liquid solar fuels can be produced using a modular approach. A simplified economic analysis is used to evaluate the cost for making diesel and other fuels. In each reaction scheme, water is converted to hydrogen electrochemically, which is later converted to a liquid fuel by the Fischer-Tropsch method. Renewable energy sources, such as wind and solar, provide power to each process in its entirety. Furthermore, costs for photoelectrochemical cells, a developing hydrogen-production technology, are estimated and compared with electrolyzer costs at optimized current densities. This approach for evaluating renewable liquid fuels can be customized as new technologies develop and cost estimates evolve. One way to address the large capital costs associated with a large-scale conversion to renewable fuels is for the government to establish a guaranteed market to buy such fuels in an amount comparable to the needs of the military. This would also help the United States meet its own mandate for a 50% conversion of the fleet to nonfossil fuels by 2021.