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New Study Proposes Using Iron to Store Hydrogen

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Hydrogen is by far the most abundant element in the universe, as it accounts for about 75% of normal matter. For that reason, hydrogen has always been the dream fuel that would one day solve humanity’s energy needs. However, hydrogen has many obstacles to overcome to become, and the biggest one is storage.

Hydrogen needs to either be cooled down to -253°C, compressed to very high pressures, or stored in metal hydrides or carbon nanotubes. Each of these is either too expensive or inefficient, but that could soon change, with Switzerland’s ETH Zurich proposing iron ore as affordable and efficient energy storage.

The idea is not entirely new; in fact, the Lavoisier Meusnier iron-steam process has been used to produce hydrogen since 1784. This time, the researchers propose a slightly different method, using iron ore, i.e., the rocks and minerals we are extracting iron from.

Basically, the study suggests a circular process, where water is used to turn the iron ore into iron oxide (rust), producing hydrogen in the process. Then, hydrogen can be fed to the iron oxide, binding to the oxygen atoms and producing water, leaving pure iron.

The research team at ETH’s Hönggerberg campus used three stainless steel reactors of 1.4 cubic meters that were filled with 2-3 tons of iron ore. According to the team, this was enough to store 10 MWh worth of hydrogen for extended periods. This would make the new process an excellent addition to any renewable energy power plant, like solar or wind power. Since it can be done at ambient pressure and with an iron ore heated to only 752 °F (400 °C), the new storage method is more efficient and should ultimately be more affordable. The reactors can also be made from stainless steel, without any worry of embrittlement from hydrogen. Finally, thanks to the cyclical process, one storage tank can be used for years before it needs to be replaced.

Article and Image Credit: ETH Zurich