In this article, a number of future energy visions, especially those basing the energy systems on hydrogen, are discussed. Some often missing comparisons between alternatives, from a sustainability perspective, are identified and then performed for energy storage, energy transportation, and energy use in vehicles. It is shown that it is important to be aware of the losses implied by production, packaging, distribution, storage, and end-use of hydrogen when suggesting a "hydrogen economy." It is also shown that for stationary electric energy storage, fuel cell electrolyzers could be feasible. Zero-tailpipe-emission vehicles are compared. The battery electric vehicle has the highest electrical efficiency, but other requirements imply that plug-in hybrids or fuel cell hybrids might be a better option in some types of vehicles. Finally, a simplified example is applied to the overall results and used to discuss the needs and nature of an energy system based on intermittent energy sources. (Contains 3 figures, 3 notes and 5 tables.)