The path of green hydrogen
26.05.2020 I Güllü Beydilli
Hydrogen is the element that occurs most frequently in our universe. It is found all around us and can be used as a climate-neutral energy carrier. Thus, the light H2 molecule could become the key to a successful energy transition. However, this will only succeed if the so-called 'green' hydrogen is put to use.
The trend away from fossil fuels and towards renewable forms of energy production and storage continues. The world population is growing steadily and requires more and more energy – especially in the course of the ongoing urbanization and digitalization of our lives.
The environmental awareness of consumers and companies has also changed: Today, more people are concerned with the effects of climate change and are increasingly expressing the desire for climate-neutral alternatives for energy supply. In this context, ‘green hydrogen’ is often referred to. It is said to be environmentally friendly and a key to a successful energy transition: But what makes hydrogen ‘green’?
Green hydrogen as energy storage
The prerequisite for green hydrogen is its’ production, aka the water electrolysis, by using electricity from sustainable sources. To ensure a constant and reliable supply of electricity from green energy sources, the surplus electricity from wind power plants & solar plants must be storable for later use.
The electricity from green sources is used for water electrolysis to split water molecules and produce hydrogen. This hydrogen can in turn be used as energy storage, stored in tanks or even underground caves and transported via pipelines, tankers or trucks. Thanks to hydrogen technology, green energy plants can be used independently of environmental conditions and thus become more reliable. Hydrogen technology offers renewable energy plants the possibility to store surplus energy produced under favourable weather conditions. Renewable energies and green hydrogen technology are therefore mutually beneficial.
Modern hydrogen technology can thus make a significant contribution to a successful energy transition. But how exactly does water electrolysis work and how can the energy be stored in the form of hydrogen so that it can later be released and fed into the power grid?
Water electrolysis – how it works
In a water electrolysis plant, electricity is passed through water, thereby initiating the splitting of the water molecules into their two components, hydrogen and oxygen. Oxygen accumulates at the plus pole, rises and escapes into the atmosphere. Hydrogen accumulates at the minus pole, from where it can be captured and stored. The stored energy from the process of water electrolysis, which is now in the hydrogen molecules, can be released again by the reverse reaction of hydrogen with oxygen. The energy is needed, for example, in the production of methanol from steelworks emissions for the chemical industry.
Carbon2Chem – Water electrolysis on an industrial scale
Since green sources, such as the sun and wind, do not continuously produce energy at the same intensity, effective storage is necessary for the supply of green electricity. The surplus generated at favourable times can be stored using hydrogen, making electricity from renewable sources available at any time – without polluting the atmosphere with CO2.
Thanks to water electrolysis, thyssenkrupp is also well on the way to achieving a low CO2 emissions balance. Under the name Carbon2Chem, thyssenkrupp experts in Duisburg are working on modern hydrogen technology and ‘recycle’ the waste gases from steel production into valuable chemical base materials. This is because hydrogen technology can be used to produce starting materials for various sectors of industry.
At the Carbon2Chem pilot plant in Duisburg, so-called metallurgical gases are processed with the aid of hydrogen to produce so-called synthesis gases. These synthesis gases are valuable chemical raw materials that serve as precursors for the production of methanol, ammonia or polymers. Substances which in turn can be used to produce fuel, fertilizer or plastics. The result: CO2 is not emitted into the atmosphere, neither in steel production nor in the chemical processes, but is instead converted into something valuable.
How hydrogen makes the chemical industry a little greener
The experts at thyssenkrupp Uhde Chlorine Engineers have further developed the alkaline electrolysis process so that it is also suitable for fluctuating power supplies from green sources. This is an important development step because conventional plants for alkaline electrolysis require a constant power supply around the clock.
The innovative plant, marketed by Dr. Lukas Lüke, product manager for thyssenkrupp water electrolysis technology, and his team, achieves efficiencies of over 80%. This simply means that 80% of the energy supplied during electrolysis can be stored. The plant is therefore designed for large and particularly efficient production of hydrogen. Added to this is the modular design of the plant, which makes any expansion easier than with traditional plants. Dr. Lukas Lüke, from thyssenkrupp Uhde Chlorine Engineers, gives us an insight into the innovative plant which can be used to exploit the potential of hydrogen:
Conditions for a successful energy transition
Based on the Paris Climate Agreement of 2015, thyssenkrupp has set itself the target of reducing its own emissions by 30% by 2030 and becoming carbon neutral by 2050. In order to achieve this, we aim to reduce emissions or achieve climate neutrality in our production, energy consumption and product life cycle. The Science Based Initiative (SBTi) has classified these climate targets of thyssenkrupp as science-based and achievable. This makes us one of only ten German companies whose climate targets have been scientifically confirmed by SBTi.
But to achieve climate neutrality – not just in our company but throughout Germany – we need significantly more renewable energy sources. However, the current capacity of green energy in Germany is not sufficient to meet current and future demand. For example, the operation of our steel mill in Duisburg alone would currently require all the renewable energies available in Germany for 12 months. Political regulations are therefore also needed to promote renewable energy sources and make a switch to climate-neutral production chains attractive for more companies. For example, it would be possible to produce hydrogen in sunny regions of the world and bring it to Europe by tanker. The first initiatives in this direction are already underway.
So, there is still a lot of room for development in the hydrogen-related technologies and a great need for renewable energy sources – for today, but above all for the future. That’s why we at thyssenkrupp are working to continuously develop our technologies.