Hydrogen powered cars sound great but there's a catch or two

Just imagine that the only emission from you car’s exhaust was a bit of harmless water! That is the dream, already realised in various prototype vehicles, of hydrogen power.
Central to hydrogen power is the fuel cell, a device which turns a suitable fuel into electricity, somewhat like a battery, and with no moving parts. A fuel cell can potentially operate at more than twice the efficiency of a combustion engine.

Fuel cells are not new, having been invented in the mid nineteenth century and used in various applications, including in the space program.
When used in a car, the electricity generated by the fuel cell is used by electric motors that drive the wheels.
This sounds so good that you’d have to wonder why we aren’t all driving hydrogen powered fuel cells cars now. What’s the catch?

First of all, hydrogen fuel doesn’t exist. It has to be manufactured using lots of energy. Most hydrogen today is manufactured from fossil fuels like coal or natural gas using a process called thermal reforming. But in the future, hydrogen will mostly be manufactured by passing electricity through sea water, known as electrolysis.
So clearly hydrogen is not a source of energy. A hydrogen economy will require lots of electricity. Not surprisingly, nuclear energy proponents love hydrogen power because it creates a further demand for electricity. But for hydrogen fuel to be sustainable it must be produced using electricity generated from renewable sources such as wind and solar.

The next problem is the storage of hydrogen at filling stations and in vehicles. It can’t be stored in existing tanks and pipes used for LPG or natural gas. Hydrogen can’t easily be liquefied and so must be stored as compressed gas. Cars will require very large tanks because you need at least five times as much hydrogen as petrol to travel the same distance. Research is continuing into better ways of storing hydrogen, but in the foreseeable future biofuels such as ethanol will likely be a more convenient fuel for fuel cells.

A final problem is that the world has 700 million cars, almost all with internal combustion engines. It will take many decades to replace most of those cars.
Because of their efficiency, fuel cells are bound to have a role to play in our future. But given the challenges, hydrogen powered cars are unlikely to be widely available for several decades.

This was originally published in the Fraser Coast Chronicle on 3 April 2007.