No sector within road transportation is more reliant on diesel than heavy-duty commercial vehicles. In the European Union, more than 97% of new medium- and heavy-duty trucks sold run on diesel. A similar figure can be seen across North America.

A gradual transition away from diesel is inevitable. As a fossil fuel, it will eventually run out. When used in an internal combustion engine, it also produces harmful nitrogen oxides (NOx) and particulate matter (PM). Advanced emissions reduction strategies have improved things, but regulations are in place to ensure that a growing quota of heavy trucks are not just ‘low emissions’ but zero emissions.

The task is to make strategic investments in technologies that are poised to dethrone diesel, but high up-front cost, a lack of clarity on performance and a lengthy return on investment makes it fraught with risk. It leaves truckmakers in a difficult position, but they are tackling the issue head on.

Meet the contestants

There are two obvious zero emissions alternatives to diesel, both…