Hydrogen - colorless, but colorful.
Gray, blue or green hydrogen? One thing is certain: Hydrogen is actually a colorless gas, yet there are many colorful names for the energy carrier. Behind them is a reference to the production method and the energy used in the process that makes the coveted H2 molecule sustainable.
The energy carrier of tomorrow
In the current discussion, hydrogen is considered the energy carrier of the future. This is primarily due to its diverse potential applications: from mobility to heat supply to conventional industry, hydrogen can serve as an efficient alternative to fossil resources. It can heat furnaces in the cement and steel industry, synthesize industrial waste gases into feedstocks for fertilizers, plastics and fuels, and serves as a basis for other important raw materials in the chemical industry.
Particularly in the steel industry - one of the most CO2-intensive sectors - hydrogen can make a big difference, as carbon is traditionally used in the blast furnaces to produce pig iron. On the one hand, this provides the energy needed to melt the iron ores, and on the other hand it serves as a reducing agent, i.e. it binds the oxygen in the iron ores, producing pure iron. In this way, the blast furnace process currently generates 85% of the CO2 emissions of the entire steelmaking process. Decarbonizing the steel industry with the help of hydrogen is therefore a huge opportunity for a more climate-friendly future.
However, the extent of this leverage and the potential for CO2 savings in industrial applications depends to a large extent on the production method of the hydrogen used.
From gray to green: it all depends on how it's made.
Gray hydrogen: Currently, hydrogen is mainly produced from fossil fuels - more precisely: from natural gas. In practice, this means that hydrogen and carbon dioxide are split under heat. After this process, the carbon dioxide (CO2) is released unused into the atmosphere. This hydrogen is called gray hydrogen. The production of one ton of gray hydrogen produces around ten tons of CO2. By way of comparison, this is about as much CO2 as a person living in Germany produces on average per year, or a commuter with a 40km commute and a medium-sized gasoline-powered car over a period of six years.
Blue hydrogen: The so-called blue hydrogen is also produced from fossil fuels. However, the CO2 produced is captured, stored or used. Therefore, blue hydrogen can be a first lever to reduce CO2 emissions in the medium term, but is not a long-term solution for a greener industry due to the negative environmental balance of fossil fuels. The long-term use of the materials or storage is crucial.
Green hydrogen: Water electrolysis uses electricity to split water into hydrogen and oxygen. If only energy from 100% renewable sources is used during this process, it is referred to as green hydrogen. This process is completely free of CO2 emissions. This is because no matter what specific electrolysis technology is used, no CO2 is produced during electrolysis. Therefore, green hydrogen is considered the energy carrier of the future and an important pioneer for a sustainable and CO2-free industry.
The potential of blue hydrogen
The switch to green hydrogen in steel production is essential in the long term for achieving the UN climate targets. Plants running entirely on green hydrogen can save several million tons of CO2 in the steel industry alone. But at present the quantities of renewable energy available are not yet sufficient to meet the constantly rising hydrogen requirements of all industries. The thyssenkrupp Steel steel mill in Duisburg alone will need around 720,000 tons of hydrogen per year in the long term. That's a whole 247 million hydrogen-filled trucks a year! Therefore, an important form of transport for hydrogen is ammonia. This can be transported inexpensively in tankers. The ammonia is then split into hydrogen and nitrogen on site. With the help of ammonia, a worldwide market for low-carbon hydrogen will be established.
Before the energy transition is complete and sufficient electricity from renewable sources is available, the use of blue hydrogen will be necessary in the medium term to avoid CO2 emissions. Because blue hydrogen also has a lot of potential. By using blue hydrogen, thyssenkrupp Steel in Duisburg can already save 20 million tons of CO2 emissions a year.
Together towards the green transformation.
Our goal is clear: thyssenkrupp aims to be completely climate-neutral by 2045. A first step in this direction is the direct reduction process, in which the iron ores are reduced by hydrogen. This means that no CO2 emissions are produced during pig iron production itself.
The decisive course for the green transformation - well beyond steel production - is being set by the colleagues at thyssenkrupp nucera and thyssenkrupp Uhde. As one of the few suppliers worldwide, thyssenkrupp nucera already offers technologies for the production of green hydrogen on a gigascale. With the right plants for ammonia synthesis and cracking, as well as storage tanks, thyssenkrupp Uhde provides the necessary infrastructure to transport Blue or green? One thing is certain: In the coming years, CO2 -neutral hydrogen will become increasingly important, especially in industry. With our various competencies and perspectives for sustainable value chains and a colorful mix of climate-friendly solutions, we at thyssenkrupp are already right in the middle of the green transformation.