01 Jun The Challenge of Storage

Source: http://hydrogen-expo.com

The transition towards 0 emission requires hydrogen. One of the challenges faced by this transition is storage as well as scaling-up production, handling and transportation.

Compressed hydrogen is the most widely used today. Gas is stored in steel or compound tanks able to withstand high pressure. Gaseous hydrogen storage needs containers to withstand 350 to 700 bar in addition to high energy levels to compress the gas. Cryogenic liquid hydrogen implies cooling the gas to about -253º, which also calls for energy to carry out the cooling process. Since the liquid has a higher density than that of the gas, it allows a more compact storage although it requires sophisticated isolation systems.

Metal hydrade compounds can absorb and release hydrogen by means of a chemical reaction allowing the storage a lower temperatures and pressures than those of the compressed hydrogen. The advantages of this system are safety (being a solid storage safety is increased), and the energy density is higher; thus smaller and lighter systems can be used. The main disadvantages of hydrades are the cooling and heating systems during the loading and downloading processes, and the time required for the processes.

The chemical hydrogen storage implies the storage within chemical compounds that permit the release of hydrogen on demand. These include LOHCs (Liquid Organic Hydrogen Carriers), and ammonia and other hydrogen carriers such as formic acid that can be storage in almost environment conditions although catalysts and energy input are necessary to release hydrogen.

New methods are being tested to avoid the disadvantages aforementioned. The said methods include porous materials and nanomaterials that store hydrogen through adsorption, solid storage using clathrates or hydrogen-absorbing glass.