Scientists say distillery wastewater could be used to produce green hydrogen

Heriot-Watt scientists claim that their new method could kill two birds with one stone by taking the estimated 1 billion litres a year of wastewater from distilleries globally to use to produce green hydrogen.

Scientists claim to have come up with a method of using billions of litres of wastewater from distilleries to produce so-called "green hydrogen" to produce clean energy.

Researchers at Heriot-Watt University in Edinburgh say their method of using wastewater from the likes of whiskey making could fundamentally transform green hydrogen, which is seen as having huge potential in theory as a renewable energy source but is still seen as way behind the likes of wind and solar in practical use.

Put very simply, green hydrogen produces energy through the electrolysis of water, while eliminating emissions by using renewable energy.

Its supporters say it could completely revolutionise clean energy, while its detractors say it is too cumbersome and costly to achieve on a mass scale — however, it has turned even the heads of sceptics in recent years as costs come down.

Ireland last year finally published a hydrogen strategy after being stalled for years, with the Government saying it will focus its efforts on the scale up and production of renewable green hydrogen in the coming years.

Heriot-Watt scientists claim that their new method could kill two birds with one stone by taking the estimated 1 billion litres a year of wastewater from distilleries globally to use to produce green hydrogen.

As well as using the water that is wasted from distilling, it would also eliminate the need for much of the 20.5 billion litres of freshwater currently being used in the green hydrogen process globally, they said.

"It takes 9kg of water to produce every 1kg of green hydrogen. Meanwhile, every 1 litre of malt whisky production creates about 10 litres of residue. To help protect the planet, we need to reduce our use of fresh water and other natural resources," Sudhagar Pitchaimuthu, a materials scientist in Heriot-Watt’s School of Engineering and Physical Sciences, said.

His team successfully used a nanoscale material — a particle that is a 10,000th of the diameter of a human hair — to allow distillery wastewater to replace fresh water in the green hydrogen production process.

Mr Pitchaimuthu said: "About one billion litres of wastewater a year is produced from the distilling industry, so the potential of this process is huge."