Hydrogen Storage Techniques

Hydrogen is the lightest chemical element. Although rare in its pure state, hydrogen atoms are part of many compounds, such as water and methane. It was first isolated in a laboratory in 1766, according to the Think Quest website. Hydrogen is highly combustible, and today it presents a nonpollutant alternative to fossil fuels. The techniques to store hydrogen include the use of high pressure, very low temperatures and the metal hydrides technique.

High Pressure

• High pressure storage includes the use of steel cylinders or tanks, glass spheres and composite tanks, such as the carbon fiber-wrapped tank, which can contain pressures up to 700 bar, according to the Energy Research Centre of the Netherlands. One bar is the unit of measure that refers to the total atmospheric pressure at sea level. Although the high pressure technique is better known and has been widely tested, it presents some disadvantages such as the large physical volume required, its high costs and safety issues.

Cryogenic Liquid

• At -253 degrees Celsius, or -423.4 degrees Farenheit, hydrogen turns into liquid. Therefore, it can be stored as a constituent of a cryogenic liquid solution that contains other compounds, such as anhydrous ammonia. Liquid hydrogen is already used in some commercial vehicles. Among the advantages of the cryogenic liquid technique is the high storage density at relative low pressures. However, a large amount of energy is required for the liquefying process, in the range of 25 percent to 40 percent of the total energy generated.

Metal Hydrides

• Metal hydrides are metals that contain hydrogen molecules, such as nickel magnesium hydride, or Mg2NiH4, and lanthanum nickel hydride, or LaNi5H6. Hydrogen can be stored in these metals without the need to pressurize or cool. Metal hydrides are cheap, abundant and relatively safe and offer a good storage capacity by volume. However, such techniques require further research to before they can be implemented on a commercial scale.