Science – The hydrogen era

About 40 years ago, I first encountered the term “hydrogen economy” while preparing a talk for a group of environmentally aware farmers. Now the term has gained increasing potency in the push to create a sustainable climate. However, hydrogen has generated considerable controversy among car manufacturers. Tesla considers hydrogen is unnecessary, while Toyota is expected to expand the development of its already popular hydrogen-powered range, the Mirai.

The prospect of a green hydrogen facility at Tiwai Point is being explored by Dr Andrew Forrest, chair of Fortescue Minerals, one of the world’s largest mining companies. Dr Forrest is in negotiations with local stakeholders and government. He forecasts that there is a rapid end in sight for coal-fired energy and steel production. The green hydrogen produced in a new Southland facility would satisfy national demand during the global transition into a new transportation era and also create opportunities for export. Interestingly, Sweden is converting its major steel production into a hydrogen-powered process. If the negotiations in Southland are successful, it will be a transformational step forward for Aotearoa in its zero-carbon journey.

I should explain that “green hydrogen” refers to industrial-scale production of hydrogen free of contaminating greenhouse gases. This is in contrast to “grey hydrogen”, which is a major industrial gas formed by the methane-shift process, which generates substantial quantities of the greenhouse gas carbon dioxide as a by-product. But green hydrogen when used either as a fuel in a hydrogen fuel cell vehicle or novel hydrogen-powered internal combustion engine (such as the revolutionary Aquarius engine) produces virtually no greenhouse gases. Aside from the elimination of greenhouse gases, the use of green hydrogen has some other strategic advantages. It reduces the need for cobalt and lithium, which are in limited quantities worldwide, and which are used in electric vehicle (EV) batteries.

Hydrogen fuel cell technology appears likely to be a primary power source for other major emerging transport applications, including electric planes, trains, buses and ships, where battery power alone would be insufficient.

The choice between hydrogen fuel cells and plug-in batteries in EVs may remain a subject for debate among manufacturers and consumers for some time. A battery EV charged solely by a national grid, which is largely powered by coal (for example, in Australia) is clearly not carbon zero. But a green hydrogen powered EV emitting only water vapour is as close to carbon zero as is practical at present. Therefore, it seems inevitable that hydrogen-powered transport will be a critical aspect of the lead-up to the zero-carbon world of 2050.

Emeritus Professor Ralph Cooney
r.cooney@auckland.ac.nz