How is hydrogen made?
Hydrogen can be manufactured in a number of different ways. The most common method at present is steam reforming of natural gas, although this process also produces CO₂ in addition to hydrogen. If water is broken down into its molecular components hydrogen and oxygen with the aid of an electric current, it is known as electrolysis. And if the electricity required for this process comes from renewable energy sources, climate-neutral or green hydrogen is obtained.
The purity of hydrogen is expressed as a numeric value. The first digit indicates how many times the number 9 occurs in the percentage figure. For example, hydrogen 3.0 equates to a purity level of 99.9 percent, while hydrogen 5.0 has a purity of 99.999 percent.
Where is green hydrogen produced in Baden-Württemberg?
The production of green hydrogen is still in its infancy in Germany. Nonetheless, there are already isolated projects focusing on the production of green hydrogen. In Grenzach-Wyhlen (in the district of Lörrach), the EnBW subsidiary Energiedienst (ED) has been operating a power-to-gas planton the site of its hydropower plant since 2018. It uses climate-neutral electricity generated from hydropower here to produce high-purity hydrogen 5.0. “At full capacity, we produce a good 400 kilograms of hydrogen every day, which is enough to fill up about 100 cars,” says André Büssers from the ED hydrogen division.
Another EnBW subsidiary is active in Heilbronn. Under the project name H₂ORIZON, Markus Wiench and his team have been producing high-purity hydrogen 5.0 using wind energy since 2019. A new form of electrolysis, the so-called proton exchange membrane (PEM), is used here. “This is a dynamic plant that can better compensate for fluctuations in the power supply,” explains Wiench. Since the wind does not blow constantly and at the same strength, such fluctuations must always be factored into the production of hydrogen using wind energy. ZEAG’s project partner is the German Aerospace Center (DLR), on whose site the facilities are also located. “In the first step, the hydrogen we produce will mainly be used for engine research here at the site,” says Wiench. Among other things, the DLR is testing hydrolox propulsion systems for the Ariane 5 rocket. With over 400 metric tons of hydrogen consumed annually, it is considered one of Europe’s biggest hydrogen users.
EnBW hydrogen project planned in northern Germany
An electrolysis plant is set to be built on the site of EnBW’s hard coal power plant in Rostock within the next four years. The plant is set to be built by a consortium of several companies, which, besides EnBW, includes the energy suppliers RWE and RheinEnergie (the latter is co-owner of the power plant) as well as the port of Rostock (Rostock Port GmbH).
The electrolysis plant has initially been designed to generate an output of 100 megawatts. However, it has a modular design – which means that it is possible to increase the output to up to 1,000 megawatts at a later date. The power plant team in Rostock will take care of operations. The electricity needed to produce the hydrogen is set to come from onshore and offshore wind turbines. Consequently, around 6,500 metric tons of “green” hydrogen are expected to be produced annually – most likely from 2026. This is set to be made available to local consumers in the Rostock area and fed into the hydrogen pipeline being built between Rostock and Berlin.
How expensive is hydrogen?
There is no standard price for hydrogen. “The price for green hydrogen ranges from five to 20 euros per kilogram,” says Markus Wiench. “The wide price range is due to the differently sized production plants and the way in which it is produced using renewable energy. Gray hydrogen made from natural gas is already available for between three and four euros per kilogram.” In Wyhlen at ED, a kilogram of green hydrogen currently costs seven euros or more. “This is partly due to the high electricity prices,” says André Büssers. If you drive to a hydrogen filling station, you pay the standard nationwide price of €9.50. A made-up price that is not so much due to the production effort involved as to political reasons. “The price of €9.50 was set against a so-called diesel equivalent. This involves comparing the fuel consumption of combustion engines with hydrogen drive systems and then setting the hydrogen price based on the equivalent diesel price,” says Wiench. “Although the hydrogen available at public filling stations is usually not green.”
How can the price of green hydrogen be lowered?
Green hydrogen can be produced more cheaply by using by-products. “Waste heat is generated both during electrolysis and in the hydropower plant,” says Büssers. “In the medium term, we will use the waste heat from the power plant to heat a new residential area. In the future, the waste heat can also be drawn off from the PtG plant and utilized.” Businesses in other sectors, such as those that supply heat, can thus benefit from hydrogen production. This kind of synergy is known as sector coupling. In a living lab funded by Germany’s Federal Ministry for Economic Affairs, ED is therefore developing a business model for the economic use of green hydrogen.
H₂ORIZON near Heilbronn is already one step further ahead. The 1 MW electrolysis plant entered regular operation at the end of 2022. “We want to show how sector coupling on an industrial scale already works in practice,” says Markus Wiench. Besides the electrolysis plant, ZEAG also operates two combined heat and power plants on the DLR site, one of which can also be operated with up to 60 percent hydrogen for research purposes in the future. This should also make the energy and heat supply in the buildings on the site more sustainable.
However, making sure that sufficient quantities of cheap electricity from renewable energy sources will be available in the future is also critical to reducing costs.
The world’s first hydrogen-powered trains are already making journeys in Lower Saxony. The “Coradia iLint” built by the French company Alstom initially ran on the test track between Cuxhaven and Buxtehude in 2019. This had a fuel cell filled with hydrogen. On one tank of fuel, the “Coradia iLint” can cover 600 kilometers.
Since August 2022, the entire Bremervörde network has been served by a total of 14 vehicles powered by fuel cells. This means that the Elbe-Weser Transport Company (evb) has now replaced its entire diesel fleet with hydrogen-powered trains. The “Coradia iLint” trains will be built at Alstom’s plant in Salzgitter.
What are the challenges associated with hydrogen production in Germany?
“At the start of the project, the electrolysis technology used was still quite new and we initially had to get to grips with it,” recalls Wiench. “We had a wind farm, a customer (DLR) and a few motivated colleagues, and we made the transition to commercial operation at the end of 2022.” The young project manager says this makes him proud, but there were some hurdles to overcome: “These systems are mainly available in the form of container systems. However, we were operating them in the building, which meant that we had to meet countless requirements in our role as operators.”
And then there is the political framework, which has still not been fully clarified. That’s because despite the direct connection to its own wind farm and the fact that H₂ORIZON does not draw any electricity from the public supply grid, it is still not fully certain whether and to what extent ZEAG must pay a levy on the electricity price. In general, however, capacity from renewable energy sources in the country must also be massively expanded in order to meet the high demand for climate-neutral electricity for the production of green hydrogen.