Superconductivity research stinks! Rotorua, famous for its lake, geyser and distinctive smell, may have been hiding a secret resource for years. Often described as smelling like rotten eggs, the stinky volcanic gas is actually hydrogen sulphide and this week researchers published in the journal Nature that it could become one of the most important discoveries to change how we generate and transmit electricity.
We know that metal wires heat up when we pass electricity through them; you only need to watch birds warming their toes outside your window as they hang out on the power lines to witness this phenomenon. This heat loss results in up to 15 per cent of the electricity generated being lost into the environment through the wires that transfer it, making the current process of getting power across the world an inefficient one.
Since the 1980s New Zealand has been at the forefront of trying to solve this power loss problem, thanks to Macdiarmid Institute researchers Dr Bob Buckley and Dr Jeff Tallon, who have led the development and patented research on materials known as high temperature superconductors. They have won the Prime Minister's Science Prize for superconductor research, with an emphasis on commercialisation of new types of electricity transferring wires. Superconductors are also crucial to MRI machines and levitation technologies like the Maglev train in Japan, thanks to their Meissner levitation effect with magnets.
What makes superconductors so exciting is that they can conduct electricity with no energy loss when cooled below a critical temperature. In the case of high temperature superconductors they still require liquid helium chilling down to a frigid -140C, but once there the single electricity-carrying electrons join up to form Coopers pairs, which move easily through the material without scattering or losing energy. The temperature requirement is one issue, but current superconductors are also limited by being made from exotic materials including barium, yttrium and cuprate containing copper - not exactly things you can buy at the supermarket.
This is where the stinky volcanic gas comes to the rescue with the development of a new type of high temperature superconductor produced from hydrogen sulphide which works at -70C. This new research opens up opportunities for use in Antarctica and brings us one huge step closer to the lofty goal of achieving superconductivity at room temperature.
With an easily sourced raw material and a record-breaking high superconducting critical temperature, there is still one big hurdle left for this smelly substance to overcome before it can hit the mainstream. And that's how to convert the gas to a solid.
Right now the method involves squashing the hydrogen sulphide gas, using a diamond anvil under a huge150 gigapascals of pressure. That's more than 100 million times atmospheric pressure, which transforms the gas into a solid metal. This is not really practical, but like most novel research it does open the door for scientists to look at ways to solidify hydrogen sulphide by tweaking its chemical composition rather than having to compress it.
I am fascinated by superconductors and excited about their potential for creating portable medical scanning devices and transferring solar energy from desert farms to all corners of the earth from a material that currently makes us turn up our noses. However, top of my nerd list has to be using them to fulfil my childhood dream of building a decked out Marty McFly hoverboard with retro LED lights and a built-in stereo to levitate around on.
This column is sponsored by Callaghan Innovation to promote the coverage of science and innovation. The views expressed are the author's own.