There is a lot of interest and hope in hydrogen, but what exactly are we discussing?
I hear a lot about hydrogen and it is difficult for me to understand exactly what is involved. So here’s why I’m offering a perspective after doing a fair degree of research.
Hydrogen is an extremely common element: 90% of the universe is composed of hydrogen (H) atoms. It is important to note that, like electricity, hydrogen is an energy carrier. It is an element that is used to transport energy from point A to point B.
The main advantage of hydrogen is its high energy density. One kilo of hydrogen can store three times more energy than one kilo of petrol, and one hundred times more than the best electric batteries!
This characteristic makes it possible to consider hydrogen as a very interesting alternative for the transport sector. Hydrogen increases the range of vehicles, especially those that travel long distances (cars, trains, heavy vehicles). Moreover, hydrogen is a gas; filling up a vehicle with a gas is much faster. While it takes 6 to 8 hours to recharge a vehicle’s electric battery, it only takes a few minutes for an electric vehicle that runs on hydrogen. Hydrogen allows both more energy to be carried, and therefore allows for longer distances to be travelled, and for a faster recharge.
However, at present, 95% of the world’s hydrogen production is made from fossil carbon resources (oil, coal, natural gas). For this reason, it is referred to as grey hydrogen. This production emits greenhouse gases and is therefore unsustainable in the event of a massive increase in the use of hydrogen.
Another option is to produce hydrogen from a very simple reaction: water electrolysis. An electric current is passed through water (H2O), which separates two molecules: hydrogen (H2) on the one hand and oxygen (O2) on the other. This process makes it possible to produce pure hydrogen in a clean way, provided that the electricity used to produce it is clean and therefore of renewable origin. Anyone interested in energy and ecological transition issues has therefore heard of hydrogen. But we can only talk about green hydrogen if it is produced from green electricity. This is where the challenge lies for an industrial scale roll-out.
The obstacles are not technological, since progress in this area has been remarkable in recent years. The issue is rather that of the primary energy source: green electricity, from photovoltaic, hydraulic or wind sources for example, must be available to produce green hydrogen. We know that the production of this type of energy is currently limited, so this is where we need to concentrate our efforts.
The state of affairs has changed considerably over the last 20 years. The technology is now advanced enough to allow its application in industrial tools and systems. The progress in performance is enormous. At the same time, the energy efficiency of fuel cells has been improved and prices have been reduced by a factor of 30 in 20 years. Cheaper and more efficient, the hydrogen sector has reached technological maturity.
At this point, I really think that hydrogen is a major asset in the transition to all-electricity. Europe is continuing to develop the sector, but the example is currently being set by Japan, which has the largest hydrogen-powered car fleet in the world and is aiming for carbon neutrality by 2050, thanks in large part to hydrogen.
I, myself, hope that the Japanese theoretical model can be applied as a practical model.
