THE HYPE ABOUT HYDROGEN H2
FOR SOMETHING YOU can’t see or smell, hydrogen holds surprising promise for Australia. It could ensure we meet our Paris Agreement commitments to reduce carbon emissions to zero by 2050 and provide us with a lucrative new export product. So, what is this remarkable stuff that makes up two-thirds of every water molecule? And if it’s so plentiful and a potential sustainable energy solution, why isn’t it already running our ships, cars and power stations?
There are two main reasons why. First, hydrogen rarely exists on its own in nature. To produce it, you have to cleave it away from the other elements with which it’s invariably associated, such as oxygen in water molecules (H2 O) or the carbon in methane (CH4). Second, it’s highly flammable – 20 times more so than petroleum.
This means that even for sustainably created hydrogen, transportation and storage are huge problems.
MOST HYDROGEN USED today is sourced, as it has been for more than a century, from natural gas and coal – both unsustainable fossil fuels. Hydrogen from those sources is known as ‘brown’. But it’s hydrogen with a more environmentally friendly adjective that all the fuss is about. This ‘green’ hydrogen is sourced from water and is possible via the process of electrolysis – also known as ‘water splitting’. It takes place in a device called an electrolyser, which uses an electrical current to split water molecules into oxygen and hydrogen gas. The reaction can be reversed – with nothing but water produced – in a gadget called a fuel cell, which generates electricity that can feed into an electric motor or the grid.
Deploying these two complementary technologies at scale