Science

What if unobtanium were the most abundant element in the universe?

Visions in science fiction of a hydrogen-powered society may be less fantastical than they first appeared

Bus Éireann driver and training supervisor Simon Byrne with the first hydrogen-powered bus to enter public service in Ireland. Photograph: Naoise Culhane

Stuart Mathieson
Thu Jul 13 2023 - 06:00

I love how science fiction can be used to critique society and tell us what past thinkers thought about how the future might look, and what concepts such as humanity and progress might mean.

Frequently, science fiction will depict a society with advanced technology that solves a contemporary problem, such as space travel, clean power generation, or even disease and death. This is often accomplished using a special substance that allows faster-than-light travel, facilitates cold fusion or reverses ageing. This type of resource is sometimes jokingly (or, in the Avatar series, seriously) called unobtanium to reflect that it would be extremely useful but is unavailable in the present day.

While unobtanium usually implies scarcity, and in the hands of unimaginative writers can serve as an analogue for oil, some skilled writers have managed to use the most abundant element in the universe to fill that function. In his 1874 novel The Mysterious Island, Jules Verne predicted a world powered by splitting hydrogen from water. The evolutionary biologist JBS Haldane used his 1924 work Daedalus to describe a future England where wind power and hydrogen storage combine to solve the finite supply of coal.

[ Ireland and Germany sign declaration on green hydrogen production ]

It is difficult to overstate how much hydrogen is out there. By an incredible margin the most abundant element, it comprises almost three-quarters of the known universe. Remove it and the next most common element, helium, and only 2 per cent of matter would be left.

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Despite its ubiquity, hydrogen was first observed in the 16th century by the Swiss physician Paracelsus. When reacting metals with acids, Paracelsus observed that a flammable gas was produced. In 1671, the Waterford-born chemist Robert Boyle noted that mixing iron and acids generated extremely flammable fumes and a flame that was hot but generated relatively little light. In 1766 Henry Cavendish published results of his own experiments reacting metals with hydrochloric and sulphuric acids, calling the resultant gas “flammable air”.

In 1781 Cavendish noticed that burning hydrogen produced water, while in 1783 the French chemist Antoine Lavoisier named the element, from the Greek hydro- (water) and -genes (born of). The same year Jacques Charles recognised a practical benefit of a gas that was lighter than air and built a series of aircraft alongside the Robert brothers. On December 1st, Charles set off from the Jardin des Tuileries in a hydrogen-filled balloon, the first crewed hydrogen flight, and alighted 40km distant. Hydrogen balloons are known in French as charlières in his honour.

By the turn of the 19th century, scientists such as Humphry Davy were experimenting with fuel cells that could generate electricity from chemical reactions, while others demonstrated that electricity could split water into hydrogen and oxygen. In the 1840s William Grove developed a fuel cell that reversed this process, combining hydrogen and oxygen to make water and electricity.

Because batteries are a mature technology, they dominate electric vehicle design. But one challenge difficult to solve is that, as batteries get bigger, they get significantly heavier and therefore more difficult to move

Oil and coal offered relatively a cheap and simple, if not particularly efficient, source of power. Hydrogen was therefore primarily used to float balloons and the first decades of the 20th century were the age of the airship, until the Hindenburg disaster in 1936. After the second World War, hydrogen research mostly focused on its applications in rocketry and nuclear weapons. As transport began transitioning away from fossil fuels, electricity from battery and fuel cells became more attractive.

Because batteries are a mature technology, they dominate electric vehicle design. Engineers have made significant progress with challenges such as infrastructure, charge time and range. But one challenge difficult to solve is that as batteries get bigger, they get significantly heavier and therefore more difficult to move.

Hydrogen is the lightest natural element, and its fuel cells are easier to scale. A standard hydrogen-powered car can recharge its cell in a couple of minutes and drive several hundred kilometres, just like a petrol or diesel engine, emitting only water while it does so. Co Antrim firm Wrightbus has even delivered several hydrogen buses to Belfast’s Metro network.

Because energy is required to produce hydrogen for fuel, it, like battery power, relies on renewable electricity to be completely zero carbon. Fortunately, Ireland has plentiful potential in offshore wind. And hydrogen, because it is so efficient, offers a reliable means of storing wind energy to counter peaks and troughs. Verne and Haldane’s visions of a hydrogen-powered society may be less fantastical than they first appeared.

Stuart Mathieson is a postdoctoral fellow in the School of History and Geography at Dublin City University

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