There are some disadvantages when it comes to hydrogen gas. These are as follows: The density of this gas is very low which makes it a compulsion for it to be compressed into a liquid state and then be stored at low temperatures. This makes the storage-related issues with this gas a little complicated. In fact, it is most of the time transported in small quantities only to avoid any sort of complications. Hydrogen energy is quite expensive. It is not enough to sustain the world’s population because even though it is available in abundance, the cost of harnessing hydrogen energy tends to limit extensive utilisation. The hydrogen gas used in fuel cells is extremely flammable. So, if it isn’t handled with utter caution and care, it can lead to fires and explosions.