Whisky making requires three ingredients: water, yeast, and a grain. However, only 10 percent of those products end up as whisky, the remaining 90 percent is wasted during distilling. These waste products are either released into the sea or turned into animal feed.
Celtic Renewables Ltd is a start-up company in Scotland that is working to reuse the waste products from the Scottish Malt Whisky industry to develop biobutanol - an advanced biofuel that can be used instead of fossil-derived fuel. This will in turn reduce oil consumption and CO2 emissions, and provide an energy guarantee for rural areas that have a booming whisky industry.
The team have refined an old industrial fermentation technique, and managed to change draff (husk residue left by fermented grains) and pot ale (liquid produced during the mashing process), into 1-butanol and ethanol - which can both be used as fuel.
Biobutanol has many benefits over bioethanol, which is commonly used as a biofuel. It has 25 percent more energy per unit volume and a lower vapour pressure, making it safer to store and handle. Another bonus is that it can be easily blended with petrol or diesel in storage tanks or retail station pumps, eliminating the need for modification in blending facilities.
The whisky industry annually produces 1,600 million litres of pot ale and 500,000 tonnes of draff from the distilling process, but Celtic Renewables' current biobutanol facilities are small-scale and unable to process this much waste.
The team hopes to get sufficient funding to allow them to establish a commercial plant, where they can revive this age-old fermentation technique to develop the fuel for our future.