Did you know that only 10% of what comes out of a typical distillery is whisky? The other 90% is mostly organic by-products with little value, that are expensive to dispose of.

Global biotech company Celtic Renewables, based in Edinburgh, Scotland, has found an innovative way to make this situation beneficial for businesses and the environment. It developed a process to transform low-value organic waste products into high-value, low-carbon chemicals and biofuels – making the whisky industry more sustainable and helping grow Scotland’s green economy in the process.

Professor Martin Tangney OBE, Founder and President of Celtic Renewables, explains how the process works, and how industries around the world can benefit.

Do what with organic waste products?!

Whisky making involves just three simple ingredients: barley, yeast and water. Water is used to extract the sugar from the barley, then yeast is added to ferment this sugary water into an alcohol. Finally, the alcohol is distilled and left to mature in oak barrels until it develops the wonderful and highly-prized flavours of fine malt whisky.

It sounds simple enough, but at the end of the process, distilleries are left with large quantities of two by-products: draff and pot ale. Draff is the residual barley left over after the sugar has been extracted, and pot ale is the broth left behind in the still after the alcohol has been distilled.

These residues are produced in large volumes – around 750,000 tonnes of draff and two billion litres of pot ale a year across the industry – and disposing of them can be very expensive. This is where we spotted an opportunity – was there a way these low-value biological materials could be transformed into something of value for business and society?

A new spin on old technology

The acetol-butanol-ethanol (ABE) fermentation process was first developed in the UK during the First World War. It was one of the largest biological industries in the world until the 1960s, when it was overtaken by the rapidly expanding petrochemical industry.

In 2007, I set up the Biofuel Research Centre at Edinburgh Napier University to explore how ABE fermentation could be used to create sustainable biofuels from organic whisky residues. Through our intensive research and development, we were able to develop the patented low-carbon technology that is now at the core of Celtic Renewables’ operations.

Essentially, this technology allows us to combine low-value raw materials such as draff and pot ale  to create a new raw material, from which we can extract high-value, low-carbon products that the country really needs – namely acetone, butanol and ethanol.

Biochemicals with multiple uses

Initially, our focus was on biobutanol, which can be used to fuel your car. This was shown by biofuel pioneer David Ramey, who in 2005 drove a butanol-powered car 10,000 miles across the USA. The advantage of biobutanol is that it’s a direct replacement for petrol and diesel fuels, with no engine modification required.

In 2017, Celtic Renewables took this a step further when we made history by powering the world’s first-ever car fuelled with biobutanol made from local whisky production residues. Although our initial research focused on biofuels, we’ve since expanded our production to making chemicals for a variety of purposes. These biochemicals play an important role in our daily lives and are used in many industries, from food and cosmetics to pharmaceuticals and hygiene products.

Benefitting business and the environment

Celtic Renewables was founded to bring the university research into industrial production, to ensure that our technology found widespread commercial applications with benefits for industries worldwide.

The advantages for the whisky industry are huge. We can save distilleries the hundreds of thousands of pounds it can cost to dispose of their by-products. We also make their operations more environmentally friendly, simply by turning low-value waste into high-value products with industrial applications across many global markets.

And it’s not just the whisky industry – this technology can be applied across the food industry, agriculture and any other industry producing organic waste, contributing to the growth of a wide-reaching circular economy.

Advanced sustainable biofuels also benefit the environment. They burn more cleanly and produce fewer emissions than fossil fuels. Producing biofuels from existing waste is also a more sustainable approach than growing crops specifically to make fuel, further reducing carbon output.

A new sustainable bioeconomy in Scotland

Our recent focus has been on completing our first commercial production plant – and Scotland’s first biorefinery – at Caledon Green in Grangemouth. Construction is now complete, after having been slightly delayed due to the onset of the coronavirus pandemic.

The plant will produce almost one million litres of sustainable bio-based chemicals each year. In this way we can turn residues from the Scotch whisky industry into a new, sustainable renewables industry that could be worth around £100 million a year – and play an important role in Scotland’s green economic recovery.

We see this showpiece plant as the springboard for our ambitious growth strategy. We envision a new, innovative bioeconomy for Scotland, and the development of large biorefineries around the world that reduce waste while creating business opportunities. This is how Celtic Renewables is helping Scotland – and the world – move towards a low-carbon, sustainable economy.

Watch the animation to see how Celtic Renewables turns residues from whisky production into useful biochemicals:

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