11 September 2025
Hydrogen is a key enabler on the way to a climate-neutral energy supply of the future. However, not all hydrogen is created equal.
There are different ways of producing hydrogen. However, in the context of decarbonisation as part of the energy transition, the carbon footprint of the different processes and the origin of the feedstocks are in the spotlight. Although hydrogen itself is a colourless gas, different hydrogen colours (essentially, colour codes) are distinguished depending on the production process. Here, we will take a look at green, blue, and turquoise hydrogen.
Production Method: Green hydrogen is produced by electrolysis of water using only electricity from renewable energy sources such as wind or solar power. This process splits the water molecules into hydrogen and oxygen, emitting no carbon dioxide. Regardless of the specific electrolysis technology used, the production of hydrogen is CO2-free as 100% of the electricity used comes from renewable sources.
Environmental Impact: Green hydrogen is the most environmentally friendly option, as it generates no greenhouse gases during production.
Current Status: Despite its benefits, green hydrogen currently makes up a small percentage (around 1%) of global hydrogen production due to high costs. However, as renewable energy becomes more affordable, the cost of green hydrogen is expected to decrease.
Production Method: Blue hydrogen is produced from natural gas through steam reforming. This process generates hydrogen and carbon dioxide, but the CO2 is captured and stored using carbon capture and storage (CCS) technology.
Environmental Impact: While some carbon dioxide is generated during the process, blue hydrogen is considered low-carbon because the CO2 is prevented from entering the atmosphere. However, it still relies on fossil fuels to power the steam reforming process.
Current Status: Blue hydrogen is seen as a transitional solution, helping to reduce emissions while green hydrogen technology scales up.
Production Method: Turquoise hydrogen is produced by the decomposition of methane (methane pyrolysis). Instead of CO2, solid carbon is produced, which can no longer escape into the atmosphere.
Environmental Impact: For the process to be carbon neutral, the high-temperature reactor must be powered by renewable energy sources and the carbon must be permanently sequestered.
Current Status: Production of turquoise hydrogen is a relatively new process and has yet to be scaled up to commercial levels – but it has the potential to become an impactful way to generate hydrogen with low carbon emissions in future.
The most common form of hydrogen production currently is grey hydrogen, in which hydrogen is generated through steam reforming methane but without capturing the greenhouse gases released during the process. This effectively makes it the same as blue hydrogen, but with a much greater environmental impact due to the lack of carbon capture and storage.
You may have also heard about other ‘hydrogen colours’ – such as black, brown, or pink hydrogen. Similarly to green, blue, turquoise and grey hydrogen, they refer to the method of production: black, brown and pink hydrogen are produced through coal and nuclear powered steam reforming of water. The rate of adoption and ultimate uptake of these technologies is not yet determined, but it’s reasonable to believe that hydrogen will become increasingly important as an alternative fuel as society takes steps to reach net zero.
Hydrogen and the SEFE group
The SEFE group is a key player in the development of a hydrogen infrastructure across Europe: SEFE connects the hydrogen production hubs with the industrial hubs and develops partnerships worldwide to procure low-carbon hydrogen on an industrial scale at an early stage. SEFE in signing a Joint Study Agreement for the long-term supply of low-carbon hydrogen from Brazil and will build up its own storage capacity in Germany. The company is also developing innovative transport solutions for hydrogen by sea and contributing to the European hydrogen network, the so-called EU Hydrogen Backbone.
‘Hydrogen will play an important role in the energy system of the future – particularly in industries that are difficult to decarbonise, such as steel, chemicals, cement or refineries. With our long-standing customer relationships and our strong positioning in the areas of transport and storage, we at SEFE are focusing on the hydrogen value chain with a long-term business model. Our goal is to ensure a secure supply of competitive, climate-friendly hydrogen for our customers.’
Understanding the different types of hydrogen is crucial for making informed decisions about energy solutions.
At SEFE Energy, we are committed to providing our customers with clear and comprehensive information about energy innovations. Stay tuned to our Insights & Resources page for more updates on the latest developments in the energy sector.
Read more on hydrogen here.