點解唔用hydrogen作日常fuel

最主要既原因係因為佢極度容易燃燒，而且燃燒時產生既能量非常大，勁過任何一種化石燃料(正因為咁，所以火箭先至用佢黎做燃料)。加上佢無色，無味，而且無臭；所以如果佢做左屋企既燃料，漏左氣你都唔會知道！如果唔好彩有人開動電器，佢比沼氣、石油氣更容易發生爆炸！
佢實在非常危險，所以淨係呢個原因，佢已經唔係日常用既燃料。

mainly because of safety, it is very difficult to be stored

hydrogen boiling pt is very low so to store it in liquid form u need to keep hydrogen in very low temperature (<-200 degree C) and extreme high pressure.

moreover, since the molecule is extremely small the gas can leak very easily than lead to fire / explosion hazardous (maybe u have heard the story of hindenburg 興登堡, an aeroboat blow up and claim many life).