A multi-fuel pyrolysis system (1) comprises pyrolysis reactor (21, 22) which pyrolyzes fuels chosen from oxygenated fuels e.g. alcohols, bioolen, biodiesel and pyrolyseolen, liquid, gaseous hydrocarbon mixtures or gas mixtures, preferably fuels e.g. diesel fuel by anaerobic catalytic reaction, and fuel cells(s) are connected downstream of the pyrolysis reactor. An independent claim is included for usage of multi-fuel pyrolysis system.