How soon can the hydrogen economy come?

Hydrogen is considered the fuel of the future: its use does not produce carbon dioxide (CO2) or any other greenhouse gas, just water (H2O). But there are difficulties with this fuel: it is very energy-intensive to produce and transport. For example, pure hydrogen for transport in ships or trucks must either be liquefied at -253 degrees Celsius or stored at a pressure of up to 700 bar, around 700 times atmospheric pressure. Nevertheless, hydrogen should play an important role in achieving a climate-neutral global economy.

“Tomorrow’s energy is water that has been broken down by an electric current,” wrote Jules Verne in his book “The Mysterious Island” in 1875. As early as 1838, Christian Friedrich Schönbein (1799 – 1868) discovered the principle of the fuel cell, with which electricity is generated from the combustion of hydrogen (H2). The American space agency Nasa used fuel cells as energy sources for their moon rockets in the 1960s. The prototype of a fuel cell tractor was developed in 1959. Nevertheless, the technology has not really been able to establish itself in vehicle engineering to this day.

BUND criticizes deliveries of hydrogen

Hydrogen is abundant on earth, namely in water. However, in order to be able to use the hydrogen as an energy carrier, a lot of electricity is required to separate hydrogen and oxygen in the electrolysis. If the production is to be climate-neutral, then this electricity must have been generated from renewable energies. Only then is it so-called “green hydrogen”. If the hydrogen is not obtained from water but from natural gas or another fossil fuel through steam reforming, this is referred to as “grey hydrogen”. If the resulting CO2 is separated and permanently stored, this is referred to as “blue hydrogen”.

On October 21, the first delivery of blue hydrogen from the United Arab Emirates (UAE) for the copper producer Aurubis arrived in the port of Hamburg. It was shipped as ammonia (three hydrogen, one nitrogen atom, NH3) because the hydrogen is easier to transport that way. But although blue hydrogen is considered climate-friendly, the Bund für Umwelt und Naturschutz (BUND) Hamburg criticizes the agreement between the federal government and the UAE on such deliveries. “The production of hydrogen from natural gas consumes enormous amounts of natural gas not only for the end product, the hydrogen, but also for the production process under high pressure and high heat,” explains Lucas Schäfer, State Managing Director of BUND Hamburg.

Focus on the domestic production of green hydrogen

Added to this is the energy loss for the conversion of hydrogen into ammonia for transport, the subsequent recovery of the hydrogen as well as for CO2 capture and underground storage. According to a study by Cornell University in Ithaca (USA), when natural gas is extracted, up to 3.5 percent can escape as methane, a gas whose global warming potential is 25 times that of CO2. Accordingly, only 53 to 90 percent of the CO2 can be separated and stored during the manufacturing process. Overall, blue hydrogen could even be more harmful to the climate than the direct combustion of fossil fuels. “For this reason, blue hydrogen is also irresponsible as a temporary solution until enough green hydrogen is available,” emphasizes Schäfer.

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On the one hand, the BUND calls on the federal government not to promote the development of a hydrogen economy at random, but to first find out where there is a need at all. On the other hand, energy sources should not primarily be imported, as has been the case up to now; instead, the focus should be on domestic production of green hydrogen. As an example, Schäfer cites the Moorburg coal-fired power plant in Hamburg, which was shut down in mid-2021 and is suitable as a location for an electrolysis plant.

This is how the availability of green hydrogen is changing

In addition, the use of green hydrogen should be limited to areas that cannot be electrified in the foreseeable future, such as certain processes in heavy industry, shipping, air traffic and parts of heavy goods traffic. Falko Ueckerdt from the Potsdam Institute for Climate Impact Research (PIK) also supports this demand. Together with colleagues, he examined how the availability of green hydrogen will change in the coming years. The study was published in the journal “Nature Energy” in September.

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The researchers analyzed the ramp-up of production capacities for green hydrogen by extrapolating known data from the implementation of individual technologies. Not only wind turbines and solar systems are needed here, but also electrolysers, which convert water into hydrogen. “Even if electrolysis capacities are growing as fast as wind and solar energy, there is strong evidence of short-term scarcity and long-term uncertainty regarding the availability of green hydrogen,” Ueckerdt summarizes the result. Both hinder investments in hydrogen end-use and infrastructure, reduce the potential of green hydrogen and endanger climate goals.

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No capacity for mass production

The EU Commission plans to produce ten million tons of green hydrogen in the EU in 2030. This requires at least 100 gigawatts of installed electrolysis capacity. Ueckerdt and colleagues assume an initial capacity of 0.92 gigawatts for 2023. Achieving the EU target would require more than an annual doubling of installed capacity. “There is no precedent in the energy environment in which a technology has been scaled up so quickly,” says Ueckerdt. But it’s not entirely impossible. In the study, the scientists refer to war-related increases in production, for example of aircraft in the USA during World War II, and to the rapid market penetration of smartphones and internet offers.

A figure from the International Energy Agency (IEA) shows how difficult it could be to ramp up production capacities for green hydrogen: For a climate-neutral global economy by 2050, hydrogen-generating electrolysers with a capacity of 850 gigawatts would have to be installed by 2030; the “Nature Energy” study cites a global capacity of just 3.5 gigawatts for 2023. One hurdle in expanding capacities is that the production of electrolysers still requires a lot of manual work and is therefore expensive because the previous capacities did not yet offer the potential for mass production.

Robot to build fuel cells

The same also applies to fuel cells. This is where a project comes in that the Fraunhofer Institute for Manufacturing Engineering and Automation (Fraunhofer IPA) in Stuttgart is implementing together with the Black Forest campus and an industrial consortium: H2FastCell. By mid-2023, the researchers will build a robotic cell for the automated high-speed assembly of fuel cell stacks. Such a stack typically consists of stacked layers of bipolar plates and membrane-electrode assemblies. Hydrogen and oxygen, often in the form of atmospheric oxygen, are introduced via the bipolar plates and react with one another in the membrane-electrode units, producing an electric current.

The robot should be able to build a stack with 400 individual fuel cells in 13 minutes. “If the throughput of the stacks is increased in this way, the basis for the industrial mass production of fuel cells is laid,” project manager Friedrich-Wilhelm Speckmann is quoted as saying in a statement from his institute. That would lower prices and make fuel cells more competitive.

Green hydrogen for the production of fertilizers?

It is also important to further optimize the structure of fuel cells, says his colleague René Schade. Precious metals are scarce and they increase production costs, which is why their share should be kept as small as possible. Because of such improvement opportunities, Schade sees great potential for fuel cells and for hydrogen in general: “It is currently the only sustainable non-fossil fuel and we need it where pure electrification is not possible or makes economic sense.”

Up to now, industry has used gray hydrogen, for example for the production of fertilizers and other chemical industry products. Schade emphasizes that green hydrogen could be used immediately to manufacture these products. Other industrial processes, such as the reduction of steel in steel production, could be increasingly switched to hydrogen in the near future. With suitable framework conditions, electrolysers could generate the green hydrogen on site and thus avoid the transport problem. In the medium term, heavy diesel vehicles, ships and aircraft could use green hydrogen, either directly or through the production of artificial fuels.

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Green hydrogen is essential for a climate-neutral global economy

Schade also thinks it is possible to generate energy in buildings with green hydrogen. However, Falko Ueckerdt from PIK warns against reckoning with this with a view to combined hot water and heating systems in apartments: “Gas boilers that are H2-ready, i.e. can be converted to hydrogen as a fuel, will certainly be available soon.” But this is for him a risky path as hydrogen is likely to remain scarce and expensive for now, while heat pumps and district heating are better suited for heating buildings. “The focus on green hydrogen should not lead to technologies that are available and energy-efficient being neglected in their further development,” emphasizes Ueckerdt.

In a publication as part of the Ariadne project, which is funded by federal funds, Ueckerdt and colleagues write: “A “blue hydrogen bridge” could increase the supply of climate-friendly hydrogen and enable an earlier transformation to hydrogen.” However, this requires certification, regulation and pricing of the hydrogen Greenhouse gas emissions in the blue hydrogen life cycle. At the same time, this option has become more expensive and less likely with the energy crisis in the EU. The PIK researcher and the BUND activist Schäfer, who categorically reject it, differ in their consideration of blue hydrogen. But all the experts mentioned agree that green hydrogen is essential for a climate-neutral global economy.

RND/dpa

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