In recent years, one coal mine after another has been closed down. Although remaining quantities of this fossil fuel are still stored there, it is quiet in many mining regions. An approach of Pennsylvania State University could, however, give former mine operators hope that their seams are yet good for something – for the storage of hydrogen.
“I think it’s highly possible that coal could be the very top selection for geological storage from a scientific perspective. We find that coal outperforms other formations because it can hold more…. A lot of people define coal as a rock, but it’s really a polymer…. It has high carbon content with a lot of small pores that can store much more gas. So coal is like a sponge that can hold many more hydrogen molecules…” Shimin Liu, researcher at Penn State, has stated.
Altogether, Liu’s team studied eight types of coals from mines in the USA to find out how much hydrogen they could take up. The coals have shown remarkable sorption properties, but what still needs to be studied are their diffusivity and permeability – characteristics that determine how quickly hydrogen can be injected and removed again.
A positive side effect would be that former seams would get a second life and economically dead mining regions might be reanimated.
Source: Penn State