Hydrogen

Close-up of an electrolyzer: this is where the actual electrolysis process takes place.

A closer look at the three most popular myths

What is the most common chemical element in our universe and currently the subject of controversy? Exactly: hydrogen, which as H2 is also a component of water and all existing organic compounds. In bound form, it is an essential building block for all living things and connects desert inhabitants with the most alien deep-sea creatures. Finally, hydrogen represents 75% of the total mass of the universe and is contained in 93% of all existing atoms.

So it is difficult to claim that hydrogen is a "new trend". Nevertheless the media coverage suggests exactly that: If you enter the word "hydrogen" into the search at "Spiegel.de", there are 212 hits for the last year alone. What is the reason for this? The answer is both sobering and simple: man-made climate change. In order to curb global warming and achieve the goals of the Paris Climate Convention, the entire human race must massively reduce climate-damaging emissions. Hydrogen is one of the most prominent hopes and energy carriers of the future. With the publication of the hydrogen strategies of the German government in June and the EU Commission shortly afterwards, hydrogen became the shooting star of the energy turnaround.

This sudden fame, however, is accompanied by myths that are put to the test here. Which clichés are true and which ones should be banished to the realm of fantasy? Find out here.

Myth 1: Hydrogen is dangerous due to the high risk of explosion and therefore unsuitable as an energy carrier

This assertion is the most popular objection when the subject of hydrogen is raised and is usually formulated something like this: "Hydrogen as the energy carrier of the future? I would think twice about getting into a car or an airplane that runs on hydrogen!"

Survey results from the past decades support this somewhat casually formulated thesis: a serious proportion of those questioned stated that they had associations with the detonation of a hydrogen bomb. The "oxyhydrogen gas experiment" known from school is also still very present to many (DWV, 2011, pp. 12,18).

But are these fears unfounded or are there justified reservations? A partial answer can be directly anticipated without much research: The way a hydrogen bomb works has nothing to do with the possible applications of hydrogen in the energy sector or industry. Its enormous destructive power is based on a nuclear reaction of different hydrogen isotopes, which only takes place under special conditions. 

Hydrogen

Hydrogen pipelines: Hydrogen is transported to its destination through pipes like these..

Irrespective of this, hydrogen in gaseous form is extremely flammable. Up to a temperature of 560 °C ("auto-ignition temperature"), however, an external impulse is required for this, for example by mechanically or electrically generated sparks or hot objects in the immediate vicinity. In general, air mixtures of 4-76 percent by volume are flammable; above a concentration of 18 percent, the air mixture is then explosive (also called "oxyhydrogen gas"). However, this must be countered by the fact that hydrogen is extremely volatile and spreads quickly upwards, which is why the danger of explosion - if at all - only exists in enclosed spaces such as garages or parking garages. If a hydrogen-powered vehicle should get into a critical accident situation in an enclosed space, safety measures such as pressure relief valves etc. still ensure that the hydrogen can escape in a controlled manner and that the H2 concentration remains uncritical.

Another point that is often ignored in the discussion about the hazard potential of hydrogen is the nature of gasoline. Gasoline is similarly highly flammable and far less volatile than hydrogen. In the event of a tank leak, gasoline vapors accumulate near the ground, even in the open air, and remain there significantly longer than would be the case with hydrogen. The fire risk is therefore present over a longer period of time. In addition, gasoline already detonates at a concentration of 1.1%. Just a reminder: an air-hydrogen mixture explodes at 18%. (Stepken, 2003, pp. 2-4)

So what is the answer to the objection that hydrogen is too dangerous as an energy carrier? First of all, H2 is a gas that reacts explosively under the circumstances described above, i.e. there is a certain potential danger. Nevertheless, hydrogen is safer than gasoline, for example. And you get into a car without fearing to die, right?

Myth 2: The necessary infrastructure is missing to use hydrogen as an energy carrier

Hydrogen

A hydrogen facility: Everything that is needed for "green" hydrogen generation can be found in this relatively small space.

Another frequently heard assertion is that Germany (and Europe) lacks the necessary infrastructure to transport hydrogen in the required quantities. A corresponding network would have to be developed completely new "on the drawing board". 

To get to the bottom of this aspect it is worth looking at the (supply) networks operated by E.ON and other distribution network operators. At first glance, the electricity networks may be obvious, but gas networks are also part of the infrastructure. Most of these gas networks are used to transport fossil gases that need to be replaced in order to achieve climate targets. Nevertheless, it would be a waste of potential if these gas pipelines were to lie unused in the future. So why not use existing infrastructure to distribute (green) hydrogen throughout the country? This is the plan we at E.ON are pursuing and we want to make our gas networks H2-ready by 2030. We plan to be able to include hydrogen and other green gases in our distribution networks in ten years' time, either from domestic producers or by connecting them to the planned hydrogen pipeline network. We are testing this very practically in a subnetwork of our regional supplier Avacon. The project is intended to illustrate the possibility of feeding hydrogen into an existing gas network at a significantly higher percentage than is currently provided for in the regulations. A complete conversion of existing networks is also conceivable.

Even if there will be "pure" hydrogen networks: There is no need to develop a completely new infrastructure "off the drawing board". We at E.ON have long been working on making our gas networks part of a new emission-free energy economy.  

Myth 3: Hydrogen is too expensive to produce

Another reservation against an expanded hydrogen economy is that the electrolysis process for the production of hydrogen is too expensive. 

At first glance, this statement is correct: Various studies place the cost of hydrogen in 2020 at about 15-25 ct/kWh (Bukold, 2020, p. 8) (Prognos AG, 2020, p. 44). For classification: Natural gas is about 3 ct/kWh. So is this claim to be agreed to unconditionally? Yes and no.

In order to gain deeper insights into the price composition of hydrogen, it is interesting to take a look at the production method. In addition to several other processes, H2 is to be produced in the future using green electricity from the electrolysis process. In very simplified terms, electricity is used to break down water (H20) into hydrogen (H2) and oxygen (O). This process takes place in so-called electrolyzers, which thus take on the role of CO2-free "hydrogen generators" as long as green electricity is used. Although I have explained above that existing gas networks are currently being made H2-ready by an upgrade, there is a lack of powerful electrolyzers that can produce the colorless gas in large quantities, both on a national and international level. This means that there is still a need for investment, which is reflected in the relatively high price of 15-25 ct/kWh. If one follows the logic further, it also follows that the price will fall as soon as there is a sufficient number of "hydrogen producers". Exactly this assumption is scientifically proven: In 2030 the costs for hydrogen will probably be only 14.5-22.8 ct/kWh and until 2050 the price will be only 12.2-18.4 ct/kWh (Prognos AG, 2020, p. 44). A study commissioned by Greenpeace calculates an even bigger price drop to only 6-12 ct/kWh in 2050 (Bukold, 2020, p. 8). In addition, the efficiency of the electrolyzers will increase considerably due to the expected technological progress, i.e. the price for the end user will continue to fall.

Regardless of the calculated costs, each of us should ask ourselves whether we as a society are willing to bear the costs of the alternative scenario. If we continue to rely on fossil fuels and energy sources, humanity will not be able to contain global warming and meet the goals of the Paris Climate Convention. And these costs will not be measured in ct/kWh.

Bibliography

Bukold, S. (2020). Blauer Wasserstoff - Perspektiven und Grenzen eines Technologiepfades. . 

DWV. (2011). DWV Wasserstoff Sicherheits-Kompendium. 

Prognos AG. (2020). Kosten und Transformationspfade für strombasierte Energieträger . 

Stepken, A. (2003). Wasserstoff – so sicher wie Benzin.

 

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