What is Hydrogen Fuel?

 

Hydrogen fuel

Hydrogen is the lightest element in the universe and the most abundant, so on paper, hydrogen fuel has a lot going for it. Although it rarely exists on its own on Earth, it can be produced using clean energy to split essentially inexhaustible water molecules, producing only oxygen as a by-product.

However, 96 per cent of hydrogen today is made directly from fossil fuels – mostly natural gas, followed by coal and then oil. This overwhelmingly uses a process known as steam reformation that releases carbon dioxide.

Humanity produces around 70 million tonnes of hydrogen each year, mainly for use in making ammonia fertiliser and chemicals such as methanol, and to remove impurities during oil refining. Proponents of using hydrogen as a clean fuel think it could soon also play a vital role in decarbonising other sectors, including lorries, aviation, and heavy industry.

Hydrogen acts as a chemical energy carrier, rather like oil or gas, that can be piped or transported to where it is needed. It stores three times as much energy per unit of mass as conventional petrol, and when it “burns” in air – releasing that stored energy – it simply combines with oxygen to produce water again.

Different types of hydrogen production are labelled by colour. “Grey” hydrogen is made from fossil fuels using steam reformation. It costs about $1 a kilogram. “Blue” hydrogen also uses fossil fuels but captures and stores the CO2. Blue is about $2 per kilogram at the cheapest. Finally, there is “green” hydrogen, produced by water electrolysis running off renewable energy. For the most part, this costs upwards of $4 a kilogram.

There is a live debate in hydrogen technology over which production methods will win out. Green is the lowest carbon approach, because blue typically captures 85 to 90 per cent of the CO2 at best. While 10-15 per cent of lost CO2 emissions may not sound like a lot, it could have significant climate change ramifications if production is scaled up. Advocates of blue hydrogen contend it will play a key role because it is so much cheaper than green hydrogen.



Read more: https://www.newscientist.com/definition/hydrogen-fuel/#ixzz6xl7CVx8N

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