We have developed 2 types of engines. The first type is the dual-fuel version. This engine can run on diesel as well as on a mixture of hydrogen and diesel. In hydrogen mode, diesel is used to ignite the hydrogen. The second type of engine can only run on hydrogen and has a spark igniter (or spark plug) to start the combustion of the hydrogen.

When the air is introduced into the engine, hydrogen is injected under low pressure at the air inlet of the cylinders. Only hydrogen is injected into the cylinder that absorbs air. In this way, hydrogen can never accumulate in the engine. By injecting (pilot) diesel, a flame is created that automatically burns all the hydrogen in the cylinder with it. Burning hydrogen generates heat and pressure which is the driving force for the engine to run.

The consumption of diesel and hydrogen depends on the load profile of the engine. At full load the engine will use 61 kg of hydrogen and 45 kg of diesel per hour. To relate these figures with automotive, a new H2 car has a 6kg H2 tank capacity, a H2 bus has 40kg H2 on board. The efficiency at full load is around 40%

Hydrogen can be stored as a gas and as a liquid. Gas is stored in pressure vessels under high pressure. In hydrogen cars this pressure rises to 700 bar. For storage in liquid form you do need cryogenic technology because you need to cool down the gas to minus 253°C. 

Hydrogen storage under high pressure is the most commonly used form of storage. This is also the usual way of transporting hydrogen via trucks with bottle trailers or pipelines. The disadvantage of this form of storage is the relatively low energy density. In liquid form you can transport 3.5 times more hydrogen per volume than in compressed form. However, for refrigerated storage it is not easy to maintain the extremely low temperature during transport.

Generally speaking, you can say that hydrogen storage will take up 14 times more volume than diesel.

As with any fuel, you have to be careful with its use and storage. Hydrogen has been used successfully by the industry in Belgium for more than 50 years. The Port of Antwerp produces 380,000 tonnes of hydrogen annually. Hydrogen has proven to be a safe fuel.

The cost of the hydrogen injection system is manageable in the total engine cost. The biggest cost for a hydrogen engine is in the supply and storage of hydrogen. Due to the lack of production volumes in those components, all valves, pipes and sensors are still quite expensive. We expect this to decrease sharply in the coming years.

The adjustments to the engine are rather limited. You need to be a motor expert to see the adjustments. The big cost is mainly in the gas tube to bring the hydrogen to the engine in a safe and controlled way. We think that this cost will fall sharply in the coming years, as soon as the consumption volume increases

A reciprocating engine produces mechanical energy, while a fuel cell produces electrical energy. Some applications need mechanical energy (ex. To move a propeller) not electrical energy. In terms of lifespan, maintenance costs and purchase price per kW the reciprocating engine is more interesting. For transportation, the dual fuel solution will be the dominant choice. A ship with empty H2 tanks can still return safely to the harbor. If you are looking at fuel cell technology, the solution will require 2 to 3 times larger storage capacity to have the same autonomy and spare-capacity needed for safe operations and this is a big cost-driver in the design of the vessel. This added (spare-capacity) will usually not be needed but required for compliance with safety-regulations. The BeHydro engines reach efficiencies of +-40% at full load. Fuel cells can reach higher efficiencies in the 60% ranges but only at low loads. From the moment the load increases the efficiency decreases a lot. In marine propulsion applications (working at average high loads) both efficiencies will be comparable.