Hydrogen is the first element, represented by the capital letter H in the periodic table. It is the fuel of the stars, the building block of the universe from which everything is created through nuclear fusion. And even if the universe is more than 13.5 billion years old, hydrogen is estimated to represent 88% of the atoms in it. Despite its abundance, H is hardly ever found in its natural form – H2 – on Earth. Most of the time it is found combined with other atoms.
Therefore, we need to extract it, using energy, to isolate atoms of hydrogen. The most common method used at the moment is by processing natural gas, predominantly made up of methane, which contains four atoms of hydrogen per molecule (CH4). The methane is heated up with steam (H2O) under pressure to create carbon dioxide (CO2) and of course hydrogen (H). Today around 95% of H is produced in this way (by steam methane reforming, known as SMR). The rest of the H is extracted using another element which is abundant and contains a decent amount of H, namely water (H2O), through electrolysis, using electricity. Forcing water under an electric current will break it down into oxygen (O2) and hydrogen (H2). Such a process emits CO2, but the amount depends on the type of electricity used. However, three quarters of the energy is wasted through the electrolysis, transport and storage of H. Other ways to extract H, such as through pyrolysis, have been used only in labs and small power plants. A few pockets of natural H have been found but require fracking methods to get it from underneath our feet.
In order to categorise the types of hydrogen extraction, there is a colour code which is supposed to help the user identify how much CO2 the hydrogen they use has generated. And I am not going to enter into the question of whether pink hydrogen (derived from nuclear-based electricity using electrolysis) is better than blue hydrogen (from steam methane reforming using carbon capture). Rather, it miught be better to ask whether we actually need hydrogen in the first place. Because H is not an energy source, except for nuclear fusion or white hydrogen (naturally found pockets of H), it is an energy vector. Like electricity, H needs to be transformed using energy. And the more ecologically friendly methods for extracting H need a lot of renewable electricity, just to match the current need for H in crucial sectors such as the production of fertilizer (NH3) or steel.
As we have seen, extracting H is a complex and energy-intensive process, which makes H an extremely volatile substance, a precious commodity. And before we start building hydrogen powerplants everywhere, while dreaming of hydrogen powering everything we use today, such as cars, planes, trucks, home heating or cooking, we have to think about what is really needed. If we don’t, we will quickly hit a technological and physical wall, after a great amount of energy and investment has been wasted.
Our thirst for ever more energy and power creates the illusion that hydrogen can be a new source of abundant green energy, when it is only a vector, using already precious energy and resources, to complexify even more a system which is already interdependent on too many things. When it comes to material life, would it not be better to simplify things? To bring them closer to home and be more conscious of our environment? To be continued…
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