The hydrogen economy is tricky
I DON’T understand Siegfried Berger’s reference to harvesting hydrogen from the oceans, gravity and sunlight. (“Why do we ignore hydrogen power”, Weekend Argus, December 17).
Producing hydrogen electrolytically is a highly energy-consuming process. It requires about five times as much energy than can be obtained from a hydrogen cell. Large solar plants could be constructed to produce the electricity, on the basis that sun power is free, but solar installations aren’t free – they require land and have to be maintained; and there’s the matter of safely transporting vast quantities of compressed hydrogen.
A chemical process can be used to produce hydrogen which only requires about twice the energy that can be obtained from a hydrogen cell – a considerably more economically viable proposition. But the process requires a temperature of around 1 000ºc. Using coal or gas to get that temperature is out of the question.
A Pebble Bed Modular Reactor (PBMR) would be one source of such heat, that being its normal operating temperature. Another reactor which uses the transuranic nuclides that remain in used PWR fuel elements is the Integral Fast (breeder) Reactor ( IFR) which operates at around 1 000ºc. While the PBMR is in limbo, four countries have IFR designs in hand and/or under construction – France, Russia, China and Japan.
Is South Africa ever likely to resuscitate its PBMR project? Will it seriously consider an IFR in its nuclear mix? I don’t know.
Although I agree about what is often referred to as the “hydrogen economy”, especially for driving motor vehicles, the practicality of achieving it would appear to be a rather distant objective.
Only when people en masse agree that the use of coal and gas must completely cease is a change likely to occur. And despite meetings such as the COP17, who is campaigning to get rid of our coal and gas-fired power stations? Especially when Eskom will soon have one of the largest output coal-fired power stations in the world at around 4 GW?
How many organisations are looking at hydrogen-propelled motor vehicle designs? We can cynically believe that the petrochemical conglomerates are resisting such developments, but they aren’t immune from public opinion.
Who is going to emerge from the wings with the power and influence to convince people of the necessity for the hydrogen economy?