Molecular hydrogen is an environmentally clean source of energy, but it is not available on Earth. Steam reforming of bio-derived compounds represents a valuable route for the generation of molecular hydrogen and has the advantage that it is CO2-neutral and it requires a limited amount of additional infrastructure for implementation. At present, suitable catalysts for selective bio-alcohol and dimethyl ether reforming into hydrogen and carbon dioxide are being developed, but their use on structured wall reactors for practical application is still under way. Among them, aerogel-based coated structures appear very promising due to their very high mass transfer rates and their ability to disperse highly active metal nanoparticles. The performance of these systems improves considerably by using microreaction technologies. Microreactors based on silicon micromonoliths together with integrated downstream carbon monoxide selective oxidation hold a promising futurefor the effective on-site and on-demand generation of hydrogen from renewable fuels in portable fuel cell applications.