What will Replace Oil? Hydrogen or Batteries?

There is an interesting sub-plot going on in the race to replace fossil fueled vehicles with something more environmentally sustainable. This is a summary of the situation as far as I can make it out.

It’s fairly universally acknowledged now that we need to stop burning fossil fuels. One way of doing this is to stop using petrol/diesel vehicles and start using electric vehicles instead. Of the electric vehicles that don’t run on wires (e.g. trains) there are two main options for power; batteries or hydrogen.

A decade ago, both battery and hydrogen powered vehicles were kicked around as potential options to move forward with. Since then, batteries have become the dominant player. Battery cars are now offered by most of the major car manufacturers, battery trains and trams are relatively common (some old, some new), we are now running battery buses in Auckland, Wellington and Christchurch, and we have a plethora of smaller battery powered devices like bikes and scooters.

Assessing The Safety Of Lithium-Ion Batteries | February ...
How a lithium-ion battery works (courtesy of chemical and engineering news)

For several years the conversation seemed to go quiet on hydrogen powered vehicles. But recently they seem to be edging back into the picture again.

In September 2018 I saw this article that says Germany has just bought the world’s first hydrogen trains. They want to replace their diesel trains to reduce emissions, and think that hydrogen is a better bet than either overhead wires or battery trains. The main driver seems to be the range. Although they are only running them on a small 100km track to begin with, they say these trains are capable of travelling 1,000km before they need refuelling – much further than battery trains could.

In April I saw this article saying that the UK has just purchased 55 hydrogen buses for trials in Aberdeen, Belfast, Liverpool and Crawley. They have used battery buses in many other cities, but one problem they often run into is a lack of capacity in their electricity transmission networks. Fast charging, particularly for a large number of buses, places extremely heavy demands on electrical infrastructure. Some cities need significant upgrades if they want to convert their entire bus fleets to batteries, which can be expensive. Hydrogen doesn’t need any such infrastructure, so the theory is that it may make economic sense in some cities, generally those without great electrical transmission infrastructure.

Heathrow and Hendon hydrogen fuel stations secure grants ...
Hydrogen pumps look very similar to petrol pumps (courtesy of Air Quality News)

Brendon Harre wrote this series arguing that we should be looking into hydrogen trains more (1 and 2).

Recently this article compared and contrasted two small U.S cities; one who has just begun operating battery buses and one who has decided to instead go with hydrogen buses. It concluded that it’s a horses for courses situation- in some cities batteries make sense, in some cities hydrogen makes sense.

How does a hydrogen fuel cell work? / ¿Cómo funciona una ...
How a hydrogen fuel cell works (courtesy of Ajusa Hydrogen Technologies)

For all their benefits, battery powered vehicles have a number of problems:

  • Lower range than hydrogen (a 50kg battery stores only about one tenth the power of 50kg of hydrogen);
  • Charging facilities need some fairly hefty transmission infrastructure, which doesn’t exist in some cities;
  • Charging can take a long time;
  • Rightly or wrongly, there are emerging concerns around the environmental  impacts of producing and disposing of batteries;
  • Hydrogen offers opportunities for transporting energy around the world. Kathy Errington suggests here that New Zealand could use our abundant renewable energy sources to produce hydrogen which could be exported by ship to countries like Japan where they don’t have much renewable energy. You can’t really do that with batteries.

At the moment battery vehicles are the mainstream solution, but it is looking like the problems listed above could give hydrogen vehicles a place in certain niche areas; longer routes, freight haulage, older cities with poor electricity transmission infrastructure, and locations without access to renewable energy sources.

A key takeaway is that both options are still in the picture, and will likely specialise into different roles. A second one is that technology is developing fast and in ten years time things could be quite different again.

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