Hydrogen is a very special atom. Its sleek one-proton-one-electron design makes it easily recognizable, and it makes up around 75 percent of everything in the universe. More importantly, hydrogen could provide a perfect source of clean power for everything from heating your shower, to launching a rocket to the moon, to powering our drones.
There are many alternatives to fossil fuels - nuclear, hydroelectricity, wind and solar power - but hydrogen may just be the one which wins out in the end. In this article we ask: what's so great about hydrogen?
Abundant
Hydrogen is quite literally the most abundant thing in the universe. The sun, for example, is around three-quarters hydrogen, and we human beings are about 10 percent hydrogen ourselves. For fuel purposes, we extract hydrogen from water, of which there is around 326 million trillion gallons on earth. Once we have the technology to make electrolysis (that is, the process of splitting the hydrogen and oxygen molecules that make up water) cheap and efficient, remote communities will be able to harness hydrogen themselves and will no longer need to rely on supplies of fuel from elsewhere.
Powerful and efficient
Hydrogen is a carrier of energy with very high efficiency. In fact, by weight, it has the highest energy content of all power sources - liquid hydrogen has around 120 megajoules per kilogram, three times that of diesel. As a result, hydrogen fuel cells are compact in comparison to traditional batteries. Fuel cells are endlessly reusable, so waste disposal isn’t an issue, and they can run while being replenished, enabling perpetual operation.
Emission-free
The byproduct of hydrogen fuel cells is water. Pure, drinkable water. The reason is simple - just as we extract hydrogen from water via electrolysis, we use reverse-electrolysis to extract power from hydrogen. This creates water.
Hydrogen fuel cells work by splitting the electrons from hydrogen atoms and routing them through a circuit to create current. This is done by feeding hydrogen through a fuel cell that has a negatively charged end (the anode), a positively charged end (the cathode), and an electrolyte substance separating them. The hydrogen enters through the anode, where a catalyst splits the atoms into their constituent protons and electrons. Both the protons and electrons are attracted to the cathode, but only the protons can pass through the electrolyte. The electrons are directed instead through an external circuit. After they have created a current in this way, they rejoin their protons at the cathode, where oxygen is fed through. The hydrogen combines with the oxygen, reversing the process of electrolysis, and creating pure water.
Why aren’t we using hydrogen in everything?
It is challenging to produce hydrogen gas. The atom itself is abundant, but not on its own – our atmosphere contains less than one part per million by volume. Currently, the most efficient way to create hydrogen is with fossil fuel-based processes, which defeats the purpose of green energy. Hydrogen harvesting via electrolysis (green hydrogen) has still not achieved practical efficiency.
There are developments though. Scientists in Australia and China recently reported finding a way to take hydrogen from sea water. This wasn’t possible until now because the salt in sea water produces chlorine gas during the separation process, which destroys components of electrolyzers.
While the hydrogen fuel industry is relatively young, hydrogen fuel cells have been used in NASA spacecraft since 1965, and it might not be long until their rockets are powered by hydrogen too. Test flights with small planes powered by hydrogen were conducted in the US and the UK in early 2023, and the Chinese state railway operator recently unveiled a hydrogen train that it estimates could replace 90% China’s diesel-powered locomotives. On the consumer side of things, both Hyundai and Toyota have launched hydrogen cars to the market.
Hydrogen fuel cells have also proven perfect for powering another carbon-friendly technology - drones. Drones promise to give society a cleaner way to deliver goods, carry out dangerous tasks, and even travel. Until now, one drawback of drones was their high energy use and consequent limited flight time. Hydrogen fuel cells allow for longer time in the air and faster speed, and the compact nature of the batteries open the door for increased storage and more aerodynamic drone designs.
As climate change becomes an ever more urgent issue, the international push to replace our fossil fuel-based infrastructures with efficient alternative fuel sources is coming to the forefront. Hydrogen-powered drones could promise the best of both worlds.
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