Off the coast of Western Australia, a battle between mega giants is unfolding. The combatants involve the world’s biggest semi-submersible platform, the longest sub-sea pipeline in the southern hemisphere, and the largest floating facility ever built. They’re all there for the same reason: natural gas – and they’re hoping to start drawing it up this month.

As several countries begin to move away from coal as an energy resource, this alternative fossil fuel, which produces 50% less carbon dioxide for every unit of energy generated, is increasingly in demand in our energy hungry world.

Consumption is forecast to rise to 177 trillion cubic feet (tcf) or 5,012 billion cubic metres by 2040, up from 124tcf in 2015, says the US Energy Information Administration.

That’s why Shell’s gigantic Prelude platform – which is 488m (1,600ft) long and displaces roughly as much water as six aircraft carriers – is competing with Japanese firm Inpex for access to gas in the Browse Basin. Although they are working on separate gas fields, those fields are connected. Shell and Inpex are essentially vying for the same resource.

“The way I describe it – I have a slide I present to clients and I have a picture of two people drinking out of the same milkshake,” says Saul Kavonic, an analyst at energy consultancy Wood Mackenzie. Prelude is a true behemoth. The largest vessel the world has ever seen

It has been designed not only to collect gas from sub-sea well heads, but also liquefy it on board at temperatures of -162C. As a liquid, the gas takes up significantly less space, making it easier to transport around the world on ships. This liquefaction would usually be done after piping the gas onshore, but Prelude can do the job herself – something never achieved on such a scale before.