21.01.22 A blue bridge Author: Jost Burger • Reading time: 5 min.

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Climate-neutral green hydrogen will be an important part of the process of achieving global climate targets, but it will be many years before it is available in sufficient quantities. In the meantime, blue hydrogen can function as an interim solution.

Hydrogen is not only the first element in the periodic table, but also one of the leading components of the energy transition. This is because the combustion of hydrogen produces no CO2, but only water. Hydrogen is a climate-friendly fuel that is ideal for use in fuel cells in cars and trains and as a replacement for diesel in the hydrogen combustion engines of long-haul trucks. It can also replace coke and coal and therefore help to reduce CO2 emissions in the steel industry, for example.

But where does hydrogen come from? It is very rare in the natural world to find hydrogen atoms that are not bonded to other atoms. Therefore, the gas has to be manufactured using industrial processes and it is identified using a color system to indicate how it has been made. Red hydrogen is produced from water by means of electrolysis using nuclear power. By contrast, green hydrogen is manufactured with electricity from renewable sources and yellow hydrogen using the electricity mix from the grid. When methane is split by means of pyrolysis into hydrogen and solid carbon, the resulting hydrogen is described as turquoise.

Orange hydrogen comes from biomass, biofuels, biogas and biomethane. Fossil raw materials, mainly natural gas, but also brown and black coal, are the sources of gray hydrogen, with the resulting CO2 being released into the atmosphere. Gray hydrogen currently makes up the largest proportion of the available hydrogen. And finally there is blue hydrogen, which is gray hydrogen that has had the CO2 captured and stored during the manufacturing process to minimize its impact on the climate.

Target of 14 terawatt hours of green hydrogen by 2030

Only green hydrogen is completely climate-neutral. This is what the German National Hydrogen strategy, which was adopted by the previous federal government in 2020, is focusing on. The strategy states that the aim is to produce 14 terawatt hours (TWh) of green hydrogen per year by 2030. To put this in perspective, German industry already uses 55 to 60 TWh of hydrogen each year and the hydrogen strategy is based on the assumption that by 2030 annual consumption will have reached 90 to 110 TWh. There is clearly an enormous gap between the demand for green hydrogen and the levels of future domestic production.

In its coalition pact, the new federal government has not only decided to continue the existing hydrogen strategy, but even intends to expand it. The planned installed electrolysis capacity of 10 GW for green hydrogen will be doubled. In addition, the coalition aims to increase the size of the current import agreements, for example as part of the H2Global project. H2Global is a private-sector foundation that purchases green hydrogen on the open market via a subsidiary and sells it to consumers in Germany at a fixed price. As the purchase price for green hydrogen on the world market is currently higher than the price that can be charged for it in Germany, the federal government intends to provide 900 million euros over the next ten years to make up the shortfall. This instrument, which is known as a “contract for difference,” enables the state to compensate for the difference in price between imported green hydrogen and fossil hydrogen until the market prices come into line with one another.

A blue transition

If one thing is clear, it is that green hydrogen will not be available in sufficient quantities for the foreseeable future. The emphasis therefore must be on blue hydrogen, which could function as a bridge technology until Germany is able to produce enough green hydrogen.
Blue hydrogen is manufactured in the same way as gray hydrogen. The most widely used process is steam reforming. The raw material is generally natural gas, which has water vapor added to it at high temperatures. The outputs of the chemical process are hydrogen and carbon dioxide, but, in contrast to gray hydrogen, the CO2 generated during the production of blue hydrogen is not released into the atmosphere. Instead, it is separated out and stored geologically, either underground (this is described as carbon capture and storage or CCS) or under the seabed (carbon capture and offshore storage or CCOS).

Debate about the consequences for the climate

The advantage of the “blue bridge” is that plenty of gray hydrogen is already being produced from natural gas, because steam reforming is a well-established, cost-effective process. However, there is disagreement about what level of greenhouse gas emissions the manufacture of blue hydrogen generates. A joint study carried out last year by Cornell and Stanford Universities in the USA came to the conclusion that the carbon footprint of blue hydrogen is only nine to twelve percent smaller than that of gray hydrogen. The reasons for this are that some of the CO2 produced during the steam reforming process is not captured and the capture, transport and underground storage processes use additional energy that in turn leads to greenhouse gas emissions.

However, the conclusions reached by the study have given rise to debate. A more recent study by the Paul Scherer Institute in Switzerland shows that when the very latest methods for capturing carbon and for extracting and, most importantly, transporting natural gas are used, blue hydrogen does help to protect the climate.

The sources are the key factor

Norman Gerhardt, head of energy economics and system analysis at the Fraunhofer Institute for Energy Economics and Energy System Technology, highlights the importance of the sources of the substances. Hydrogen imports will only be competitive if the hydrogen is imported in gaseous form via a pipeline. In addition, the natural gas used to produce gray or turquoise hydrogen can only come from Siberia in the long term, because European gas deposits are limited. “However, this involves higher emissions as a result of the uncontrolled release of methane during the extraction and, in some cases, the transport of the natural gas in the pipeline,” he says and goes on to explain that offshore extraction in the North Sea produces much lower levels of emissions than onshore extraction in Russia. From a climate perspective, that is not a realistic option, which is why Gerhardt sees blue hydrogen at best as an interim solution, providing that it comes only from European sources. By contrast, products such as synthetic kerosene and ammonia produced from green hydrogen could be imported by ship.

Uwe Weichenhain, a partner at Roland Berger and an expert on energy and infrastructure, takes a pragmatic view of the situation: “Between 12 and 17 kilograms of CO2 equivalents are produced for every kilogram of gray hydrogen. In the case of blue hydrogen, the emissions amount to four to eight kilograms, depending on how the figures are calculated. That’s still better than nothing.” Weichenhain points to the close links between the natural gas industry and the production of blue hydrogen. “The large natural gas producers will soon become involved. The decisive factors for the cost-effectiveness of the process are the transport and storage of CO2.” He does not believe that sufficient quantities of green hydrogen will be available in Europe in the foreseeable future. Therefore, he is of the opinion that blue hydrogen will play an important role in the hydrogen economy for a long time to come.

Norway: A blue hydrogen pioneer

The Norwegian gas producer Equinor, for example, is already putting the process into practice. From 2027 onward, the “H2morrow steel” project aims to transport Norwegian natural gas via the existing infrastructure to hydrogen production plants off the German or Dutch coast. The CO2 that is separated out will be compressed in storage facilities off the Norwegian coast in the Norwegian Continental Shelf. The blue hydrogen will be transported via hydrogen pipes to the ThyssenKrupp steelworks in Duisburg.

The International Association of Oil and Gas Producers (IOGP) lists more than 60 projects in Europe involving the separation, compression and reuse of CO2 generated during hydrogen production. Most of these projects are still in the early stages, but it is already clear that blue hydrogen will have a key part to play in the long-term future of the energy sector.


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