Hydrogen is extremely flammable when it is mixed with very small amounts of air. The liquefaction of hydrogen requires cooling to a temperature of minus 253 degrees Celsius and subsequent storage in cryogenic containers. The advantage of liquefied hydrogen is its high density compared to compressed gas, which means that more energy can be contained in a given volume for easy transportation.
Liquid hydrogen is essential in a government campaign to expand the use of fuel cells. Dongsung Finetec and ABS, a U.S. classification society, have jointly developed a fuel tank for liquefied hydrogen. If technology development is successful, Dongsung Finetec said it can be used for ships. In September, South Korea's Hyundai shipbuilding group launched a joint project to develop a liquefied hydrogen fuel tank for ships.