Hydrogen has a great value by itself – for example the chemical industry utilize it. The most useful and expedient way of utilization is to use it as fuel in the public transportation. The biggest benefits of renewable hydrogen driven HHICE buses are the CO2 and exhaust gas emission free operation and at the same time soften the dry urban climate by a little water vapour. The Hydrogen Hybrid Internal Combustion Engine works just like diesel or gasoline IC engines, but instead of petrol or gas oil, in this case Hydrogen is combusted. The hydrogen is stored in high-pressure vessels on the roof of the bus. With combusting the hydrogen, which already can be termed as fuel, the IC engine drives a generator at a constant (1500 rpm) revolution and the electric energy produced this way will drive the electro-motors located at the wheels. Since the IC engine is able to run at a low and constant revolution, this driving system effects an economical operation.