A Scottish company has developed a commercial scale method of producing biofuel capable of fuelling cars from the unwanted residue of the whisky fermentation process.Edinburgh-based Celtic Renewables developed its process of producing biobutanol at industrial scale in Belgium and was recently awarded a £11 million ($16.7 million USD) grant by the British government to build a bespoke facility of its own in central Scotland.Professor Martin Tangney founded Celtic Renewables in 2012 as a spin-off company from Edinburgh Napier University. Tangney’s team re-adapted a fermentation process called Acetone-Butanol-Ethanol (ABE) originally used 100 years ago, but abandoned due to the cheaper cost of petroleum at the time.Tangney’s ABE process involves blending pot ale and draff – two residues that make up 90 percent of the distillery output. Draff consists of the sugar rich kernels of barley which are soaked in water to facilitate the whisky fermentation process, while pot ale is a yeast liquid that contains copper and is left over after distillation. Scottish distilleries produce around 750,000 tonnes of draff and two billion litres of pot ale every year.”In the production of whisky less than ten percent of what comes out in the distillery is actually the primary product,” said Tangney. “The bulk of the remainder are these unwanted residues – pot ale and barley. What we can do is combine these two together, create a brand new raw material, apply a different fermentation technology and convert the residual good material in here into high-value products and in particular this – biobutanol, which is an advanced biofuel which is an exact replacement for petrol or diesel.”
