Study reveals how whisky distilleries could brew up green hydrogen
Treating around one billion litres of global distilling industry wastewater could cut green hydrogen’s ‘extensive freshwater footprint’, research from Heriot-Watt University finds
Around one billion litres of wastewater from the global distilling industry could be used to produce green hydrogen by harnessing materials developed by scientists at Heriot-Watt University, new research has suggested.
Edinburgh-based scientists have developed a method of using wastewater from the whisky production process to create green hydrogen, boosting hopes the technology could reduce the water footprint of a hydrogen industry which already consumes 20.5 billion litres of fresh water a year.
Dr Sudhagar Pitchaimuthu, a materials scientist in Heriot-Watt’s School of Engineering and Physical Sciences, led a team that has developed a nanoscale material – a particle a fraction of the diameter of a human hair – called a nickel selenide that can be used to treat whisky wastewater so it can be reused for hydrogen production.
Unlike fossil fuels, hydrogen does not emit carbon when it is burned and has consequently been touted as a sustainable fuel for transport, source of home heating, and feedstock for industrial sites, including breweries and distilleries.
While electricity generated from renewable sources is used to power electrolysis – the process which produces hydrogen by splitting water into hydrogen and oxygen – for green hydrogen production, electrolysers only work with fresh water and typically fail when applied to wastewater.
However, using its nickel selenide material scientists at Heriot Watt have overcome this challenge and produced similar or slightly higher quantities of green hydrogen from wastewater versus freshwater.
“Using industry wastewater means we can reduce the extensive freshwater footprint associated with green hydrogen production,” Dr Pitchaimuthu said. “Our research also shows how we can use the world’s resources more sustainably to produce clean energy.
“It takes 9kg of water to produce every 1kg of green hydrogen,” he added. “Meanwhile, every one 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. So our research focused on how to use this distillery wastewater for green hydrogen production with a simple process that removes waste materials present in the water.”
Authored by PhD student Michael Walsh the report, titled From brew to clean fuel: harnessing distillery wastewater for electrolysis H2 generation using nano scale nickle selenide water oxidation catalysts, has been published in the Royal Society of Chemistry journal, Sustainable Energy & Fuels.
The research was funded by Heriot-Watt’s School of Engineering and Physical Sciences and completed in tandem with the University of Bath’s Department of Chemical Engineering and The Scotch Whisky Research Institute.
According to the report, distilleries in Scotland alone produce an estimated one million litres a year of wastewater from whisky production processes.
Next steps for the research team include developing an electrolyser prototype and scaling up production of the nickel selenide nanoparticles.
Scientists will also continue to analyse distillery wastewater to discover whether other materials of value could be salvaged from it, alongside hydrogen and oxygen.
Heriot Watt’s whisky wastewater breakthrough follows broader innovation across UK’s distilleries including the launch of £45m plans to transition the UK’s largest malting site to biomass and electric boilers. Moreover, in a UK first, single malt whisky maker Jura partnered with University of Hertfordshire last year to deploy a “self-repairing” CO2 absorbent building coating at its beachside distillery in the Inner Hebrides that could turn the site into one of the world’s unlikeliest carbon sinks.
