Eli5: If using hydrogen as fuel/energy requires splitting water molecules (H2O), will we not end up using heaps of water and then run out of drinking water?


I keep seeing hydrogen fuel promoted as the environmentally friendly fuel option of the future, will this not need lots of water?
A war over oil is bad enough, but wars over water are much scarier.

In: Technology

No. The excess product (i.e. the exhaust) of hydrogen power (both through burning and fuel cells) is water so it’s returned straight into the water cycle

First, any burned hydrogen turns back into water. Second, with the amount of water on the planet there’s no chance we’d use it all but we can deplete drinkable water in certain areas. Third, hydrogen fuel (not thermonuclear) is not a source of energy, it’s a way to store energy. You spend energy to turn water into hydrogen and then reclaim this energy (minus all losses) when you burn that fuel.

When you burn hydrogen as fuel, you combine hydrogen and oxygen, resulting in some energy and some water.

Fun fact: using any hydrocarbon as fuel (methane, propane, gasoline/petrol, alcohol, wood, etc) results in water being produced, because the chemical reaction is combining oxygen with the fuel, and some of the hydrogen in the hydrocarbon reacts with some of the oxygen, resulting in water. Of course, plenty of other compounds are also produced, many of which are dangerous to health, but there’s water being produced too.