Among green energy advocates, coal is reviled as the dirtiest and smoggiest of fuels. 

However, it might still have a role in the clean energy transition as a place to store hydrogen.

Hydrogen is picking up its pace in the green energy sweepstakes now that various technologies are emerging that can extract hydrogen from water to power fuel cell vehicles—so-named “green” hydrogen, as we have highlighted in our “Special Report: The Emerging Hydrogen Economy” (13 Apr 2021) and other articles.

The problem with hydrogen is storage: it’s very flammable and needs to be kept under pressure, which requires sturdy storage tanks and various controls.

Researchers have tried storing it as powder, paste, and in cartridges, but none of those concepts have yet proven market-ready.

Coal might be an answer.

Coal is shot through with microscopic pores that can be packed full of gas. It already is known to store methane, so scientists at Pennsylvania State University saw no reason why coal couldn’t do the same for hydrogen.

To test their idea, they built a pressure chamber that could push hydrogen into coal, then tried eight different varieties of coal as hydrogen storage “batteries.” They found that Virginia’s bituminous coal and anthracite from Pennsylvania held the most hydrogen.

Next, the research group will see how quickly hydrogen can be pumped into and sucked out of various varieties of coal to see if the idea is economically viable.

TRENDPOST: Coal towns have been hit hard by the shift to green energy. Repurposing coal deposits as storage batteries for hydrogen could revive regional economies, creating jobs and restoring a sense of purpose.

If coal deposits can store energy, it would be practical to build hydrogen extraction plants in the same places, creating even more skilled jobs.

Just as important, coal could play an economic role by staying in the ground.