Two examples are considered in this work in order to show possible settings for decision making in the strategic field of energy: transport vehicles and wastewater treatment plant that are powered by a fuel cell, The environmental impact, measured by evaluating hydrogen life cycle as fuel, varies depending on the source of hydrogen, the process, and the complexity of the productive chain. Nowadays, starting from this point of view, it is possible to get a lot more benefits when hydrogen is directly produced in situ from renewable sources of energy and it is used to make a fuel cell work, as an alternative to an external electric energy source, Future work must be focalized to decrease technological development gap between fuel cells and clean hydrogen extraction, before use of fuel cell would be massive.