"But how do you produce hydrogen?"
"To produce hydrogen with green energy, you need to go back to electrolysis, as Norsk Hydro did 100 years ago. Initially, and mostly still, alkaline electrolysis is used—a solution with an alkaline electrolyte. However, it is better to use a solid electrolyte in the electrolyzer and the fuel cells. For example, this is what is used in hydrogen cars today. The technology is called PEM, and it is based on using a polymer membrane that conducts ions, in this case, protons," explains Norby.
"Another option is the so-called SOFC (Solid-oxide fuel cell), where a solid oxide electrolyte is used as an ion conductor at very high temperatures - about 800 degrees. With them, one can electrolyze water vapour more efficiently and create efficient fuel cells that can handle many types of fuel. The downside is that the temperature is so high that the materials degrade rather quickly.
Blue hydrogen as an energy carrier
This is where we get into Norby's expertise: Proton-conducting ceramic materials. It is a middle ground between PEM and SOFC.
"We have developed a material that is ceramic but conducts protons just like the polymers do. This can be done at lower temperatures than with SOFC. It can be used in electrolyzers and fuel cells. But the most interesting thing right now is to use it in reactors where we can pump out hydrogen from a mixture of natural gas and water vapour in one step. What remains is a stream of CO2 that can be stored under the seabed on the continental shelf. Natural gas turns into hydrogen with carbon capture, in one step. It is the world's most efficient process for making blue hydrogen!
"But when the hydrogen is produced, what about storage and transport?"
"It's possible to store hydrogen, but it takes up a lot of space and costs a bit of energy. Ammonia can be an alternative for that," says Norby.
"Ok?"
"Almost all hydrogen in the world goes to the production of ammonia for use in artificial fertilizer. But you can also make blue ammonia directly, which is easier to transport than hydrogen and therefore is a marketable energy carrier."