A source of hydrogen is needed in the developing hydrogen economy, and many technologies are available for producing hydrogen from both conventional and alternative energy resources such as natural gas, coal, atoms, sunlight, wind, and biomass. The following paper summarizes the economics of producing hydrogen from each of these sources and gives an overview of the energy resource for each feedstock. The results of the analysis show that the most economical sources of hydrogen are coal and natural gas, with an estimated cost of 0.36-1.83 $/kg and 2.48-3.17 $/kg for each energy source, respectively. Alternative energy provides hydrogen at a higher cost; however, fossil fuel feedstock costs are increasing as technology enhancements are decreasing the cost of alternative energy sources, and therefore alternative energy sources may become more economical in the future. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.