Hydrogen

SOLID STATE

Solid hydrogen is the solid state of the element hydrogen, achieved by decreasing the temperature below hydrogen's melting point of 14.01 K (−259.14 °C; −434.45 °F). Solid hydrogen storage is a technique to use solid materials to store hydrogen under certain temperature and pressure conditions. 

USES

Nearly all of the hydrogen consumed in the United States is used by industry for refining petroleum, treating metals, producing fertilizer, and processing foods. U.S. petroleum refineries use hydrogen to lower the sulfur content of fuels.

LIQUID STATE

Gaseous hydrogen is liquefied by cooling it to below −253°C (−423°F). Once hydrogen is liquefied it can be stored at the liquefaction plant in large insulated tanks.

USES

Liquid hydrogen is used in large volumes in the space program as a primary rocket fuel for combustion with oxygen or fluorine, and as a pro-pellet for nuclear powered rockets and space vehicles. Although used more commonly in the gaseous state, hydrogen is stored and transported as a liquid.

GASEOUS STATE

Hydrogen's boiling point is incredibly low – at just under 21 degrees Kelvin (roughly -421 degrees Fahrenheit), liquid hydrogen will turn into a gas.

USES

Hydrogen can be used in fuel cells to generate electricity, or power and heat. Today, hydrogen is most commonly used in petroleum refining and fertilizer production, while transportation and utilities are emerging markets.