Future promise of hydrogen: extinguishing fires with champagne?

Status: 03.10.2022 1:19 p.m

Hydrogen is considered by many to be the energy source of the future. However, studies show that although H2 is climate-friendly to use, it is costly and energy-intensive to implement – and therefore relatively inefficient.

Hydrogen is set to become the green energy of tomorrow in many sectors. The use of hydrogen is being promoted, especially in terms of heating buildings and in the transport sector. The gas is to be used in aviation and shipping, but also for cars and trucks.

Not really an option in private transport

However, the planned use in private transport has been criticized by experts. “Hydrogen is a scarce and expensive energy source, so it is the ‘champagne’ of the energy transition,” explains Claudia Kemfert, energy economist at the German Institute for Economic Research and member of the Advisory Council on Environmental Issues.

Hydrogen produced with renewable energies is sustainable and emission-free; Regardless of this, the energy expenditure is high, according to Kemfert. This explains, among other things, the high price of green fuel. The direct use of electricity is more efficient and therefore cheaper. This is possible in many areas, such as building heat and motorized private transport, for example with electric cars, says Kemfert.

The Federal Environment Agency (UBA) is also critical: “Compared to an electric car with an overall efficiency of 75 percent, using this type of H2 produced from electricity is inefficient and makes little ecological sense.”

Missing infrastructure

Another problem is the transport of hydrogen, says Harry Lehmann, director of the PtX Labs Lausitz. If you want to transport H2 by ship, you have to liquefy it. To do this, however, the gas has to be cooled down to minus 252 degrees. While this would be feasible, it would require a large amount of power, resources and infrastructure changes.

The most energy-efficient alternative for transporting hydrogen from A to B is via pipelines – however, this requires an infrastructure change in Germany and Europe in order to be able to do this.

Flying in a more climate-friendly way?

However, there are areas in which the use of hydrogen or its derivatives is necessary in the long term, according to the UBA: These include above all the chemical industry, the steel industry as well as shipping and air traffic. Hydrogen and derivatives such as e-fuels, i.e. synthetic fuels, already play an important role here, and only in these areas should they be publicly funded, according to Kemfert.

Aviation and shipping could become more climate-friendly by replacing conventional kerosene with synthetically produced power-to-liquid (PtL) fuel. The manufacturing process of PtL fuels is simple in itself, but requires a lot of energy: First, water is split into oxygen and hydrogen by electrolysis. In a special chemical process, CO2 is added to the resulting hydrogen; synthetic fuel is produced from this. Also crucial here: The electricity used in the electrolysis must come from renewable energies.

In the future, green PtL kerosene will also be produced in this way. This would have the advantage that “up to 50 percent of kerosene from this route can already be mixed with aviation fuel,” says Lehmann. Another advantage of PtL kerosene: It does not require any infrastructure changes in terms of transport, since it can be transported like fossil fuel.

Five times the amount of electricity required

On the other hand, the production of PtL kerosene consumes five times the amount of renewable energy compared to the direct use of electricity. “For this reason, PtL kerosene should only be used in areas where direct use of electrical energy is currently not possible, i.e. in air and sea transport,” explains Lehmann. The inefficient use of H2 and PtL fuels in areas where there are more efficient alternatives is not only expensive, but also consumes important resources.

Felix Matthes, research coordinator for energy and climate policy at the Freiburg Öko-Institut, sees two scenarios: In the best case, the focus in the coming years will be on areas in which the use of H2 is necessary. The worst case, however, is that political capital and the limited funds available are wasted on a multitude of projects. According to Matthes, he currently fears that the latter scenario will be used.

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