For heavy duty trucking, hauling, shipping, and ploughing, diesel has been the stalwart fuel of choice since the development of the diesel engine over 120 years ago. With high thermal energy efficiency and abundant, convenient liquid fuel, diesel is hard to beat. Whole armies are powered by diesel – including some submarines – and many industries would grind to a halt without it.

But there’s a dark side to diesel: pollution, noxious exhaust gasses and carbon emissions. Despite the fact that a modern diesel truck produces less smoke in 200km than grilling a burger, there are millions of older engines that are hardly clean. Diesels can run on vegetable oils, and billions of gallons of biodiesel are consumed every year, but that competes with food crops and doesn’t do enough to combat climate change.

Hydrogen has been touted as the ultimate clean fuel, and can be extracted from water using solar power for a net zero solution. But it’s costly and difficult to handle, and relies on vast quantities of surplus ‘curtailed’ power to be viable. Infrastructure to store and transport hydrogen to where it’s needed is complex and underdeveloped.

Now there’s an alternative. Liquid ammonia is easily stored, transported, and distributed, and can be used both in combustion engines as well as feedstock for electric fuel cells. It’s proving itself as a zero-emissions substitute for diesel in tractors, trains, and ships. Recent breakthroughs have reduced emissions on the production side too, and now ‘green’ ammonia is becoming mainstream.

So, for heavy duty hauling and shipping, who needs hydrogen?