Hydrogen is the lightest chemical element (H2) on earth and is the most widespread in the universe. On earth it hardly exists in its pure form, but is found almost exclusively in combination with other elements, particularly with oxygen (in water) and with carbon and hydrogen (in living matter and fossil fuels).  Hydrogen is therefore not a recoverable fuel (such as coal, oil, natural gas or uranium) but has to be produced.

 

A strong benefit of hydrogen is that it can be produced from a very wide range of raw materials and processes. Some 500 billion m³ of hydrogen is already being produced annually for the use of the (petro)chemical industry in particular.

 

This industrial hydrogen is currently being produced almost exclusively from natural gas via a process of reforming. This process is used on a large scale in industry and its realisable yields and concomitant emissions of environmentally polluting substances are known.

 

For specific applications hydrogen is produced via the electrolysis of water by means of the classic reaction: 2 H2O → 2 H2 + O2: with this water electrolysis the total yield and emissions are entirely determined by the source of the electricity that is being used.

The conventional way of producing hydrogen from natural gas is not a sustainable means of producing hydrogen due to the limited nature of natural gas supplies and the emissions associated with the production process.

 

Electrolysis of water on the basis of green electricity does offer the perspective of sustainable hydrogen, especially because hydrogen is an appealing energy carrier for storing energy. During times of ‘excess’ or ‘economically unattractive’ sustainable electricity (for example, from wind energy) this ‘surplus’ can be converted to sustainable hydrogen. This sustainable hydrogen can then be used at a later stage – for example, for transport applications (such as buses for public transport) – or the sustainable hydrogen can be converted back to electricity at times of high demand for electricity.

 

Compared to electricity, where storage is a problem (weight and volume), hydrogen thus provides the possibility of achieving a more compact and lighter storage of energy. As a rule hydrogen is currently stored at 200 bar, but future developments tend towards 700 bar, making the storage volume very limited. Work is also being done towards the efficient storage of hydrogen in liquid form.

 

The storage of hydrogen, therefore, does indeed offer sustainable possibilities for use in vehicles (instead of or in combination with batteries) or as energy buffer (for example, in combination with fluctuating renewable electricity from the sun, wind, water,…).

Hydrogen can be converted very efficiently to electricity and heat by means of fuel cell technology. Fuel cells are energy systems which convert hydrogen and oxygen/air into electricity, heat and water. During this energy conversion process, which can take place at relatively low temperatures (from 70 °C), there are no emissions of environmentally polluting substances (assuming that hydrogen is the basic material). With fuels cells, moreover, very high electricity yields can be realised (not affected by the Carnot cycle).

 

An important trump card of fuel cells is that the technology can be applied very widely from W’s to MW’s: applications vary from energy supply in portable systems (laptops, cameras,…), by way of vehicles (scooters, fork-lift trucks, cars, buses, trains, ships,…) to stationary systems (cogeneration, power stations,…).  In contrast to the production of hydrogen, fuel cell technology is not yet in a commercially viable phase. The first extensive demonstration projects show clear potential, but currently the costs are still too high and the life span and reliability of the systems are still too limited. At present, therefore, the use of hydrogen as basic material for more classic ‘prime movers’ such as piston engines is being tested in parallel with the testing of fuel cells. The piston engine can certainly play a role in a first phase towards the transition to hydrogen as energy carrier.  

 

From the above it is clear that hydrogen and fuel cells can play an important role in the energy supply of the future, in which the crucial challenges will be at the level of the security of energy supplies and minimising emissions of substances that pollute the environment.

In Flanders a number of players, some of them among the best in the world, are active in the field of hydrogen and fuel cell technology at the industrial as well as the research level. In the field of alkaline systems (fuel cells and well as electrolysers) the best performing systems are developed and produced in Flanders. In addition, Flemish companies are collaborating with leading companies in the automotive world on the key components of hydrogen technology (including membranes, catalysts) in order to achieve the desired product specifications. Also among end users a Flemish bus manufacturer is one of the leaders in the field of integrating fuel cells in public transport.

 

The strength of Flanders is that the available technological trump cards can cover the entire chain from hydrogen production to the end user. For the future, targeted innovations can stimulate or create new industrial activity in all parts of this sustainable chain.

Use half the electricity of an offshore wind farm to produce hydrogen, and you will have enough hydrogen to keep the hybrid buses of ‘De Lijn’ in Flanders on the road without using fossil fuels and without emissions.  And this can all be realised with Flemish developers of technology: an innovation trajectory that is filled with promise !!!