Detailed explanation
Blue hydrogen is a form of hydrogen produced by the vapour reforming of natural gas. In this method, natural gas is heated with water vapour, producing hydrogen and carbon dioxide (CO2).
The hydrogen gas is then utilised. The carbon dioxide, on the other hand, is captured and stored instead of being released into the atmosphere. This storage takes place using the Carbon Capture and Storage (CCS) process.
CCS involves capturing the CO2, transporting it and finally storing it in geological formations. These include, for example, disused oil and gas reservoirs or layers of rock containing salt water. The technology has been tried and tested for a long time and is being used successfully in various projects to minimise CO2 emissions.
Blue hydrogen offers a bridging technology for the decarbonisation of various industrial sectors. Especially in the steel and chemical industries, where emissions are difficult to avoid.
A key aspect in the assessment of blue hydrogen is the problem of methane leakage along the natural gas production and transport chain. Methane is a greenhouse gas that is around 25 times more harmful to the climate than CO₂, and even small leaks can have a significant impact on the environmental footprint of blue hydrogen. While CCS technologies can capture up to 95% of the CO₂ produced, a small proportion of emissions remain unbound, limiting complete climate neutrality.
Compared to green hydrogen, which is produced exclusively with renewable energies, blue hydrogen remains a transitional solution. With decreasing production costs and the scaling of electrolysers, green hydrogen is expected to become increasingly available and cost-efficient. The use of blue hydrogen therefore makes sense, especially in the current phase of transformation, in order to support industries that are difficult to decarbonise on their path to climate neutrality.
