If worries over the environment are keeping you from the local pub, then it’s time to raise a glass. Scottish start-up Celtic Renewables, based in Edinburgh, has achieved proof of concept in producing biofuel and other useful products from the waste by-products of the country’s £4.3 billion (US$6.8 billion) whisky industry.

Specifically, the company is turning draff, the sugar-rich barley kernels that aid the fermentation process, and pot ale, the yeasty liquid heated during distillation, into biobutanol, which can be used as a direct substitute for fossil fuels. Biobutanol is a drop-in fuel, meaning it can go straight into the tank without modifying the car’s engine, and can be blended with diesel and biodiesel. The company is also producing solvents and high-grade animal feed.

Research into the process was originally undertaken by Professor Martin Tangney, director of the Biofuel Research Centre at Edinburgh Napier University and founder of Celtic Renewables. Tangney and his team focused on applying well-established ABE fermentation technology to biological wastes and residues. “ABE” stands for Acetone-Butanol-Ethanol, which is produced from a fermentation process using bacteria and starchy feedstocks in an anaerobic (or oxygen-free) environment; a process akin to beer making.

The process starts by mixing draff and pot ale into a slurry that’s then fermented into a broth, which creates byproduct gases, such as hydrogen and CO2. The broth is distilled to produce butanol, acetone and ethanol, while the left over solids are separated and dried, then treated to produce high-grade animal feed.

According to Celtic Renewables CEO Mark Simmers, what the company does is similar in process and results to the biofuels produced from corn and sugarcane. And while Iowa and Brazil are ideally suited for growing those respective crops, one of the most voluminous feedstocks in Scotland are the by-products from the whisky industry. To be more exact, there are more than 2.8 million tonnes (3 million tons) of waste produced by the industry each year, which makes it an obvious local choice for biofuel conversion. Plus, Martin and a number of his team had previous experience and knowledge of the whisky industry.

As an added benefit, the draff and pot ale are consistently produced almost year round, which means there is virtually no seasonal variation. And unlike corn and sugarcane, which displace food crops and can potentially create food shortages, and their production is a net environmental negative, the use of whisky dregs is a win-win. Not only can its derivatives be a direct replacement to fossil fuels and other petroleum products, but they improve the environmental impact of the current disposal routes of whisky by-products.

Scotch whisky is made up of three ingredients: water, yeast and grain, typically barley. But as little as 7 percent of what comes out of the distillery is actual whisky. Since the remaining draff and pot ale have no commercial value, they represent both an operational and environmental cost for distillers to dispose of. That issue is solved by Celtic Renewables, which also functions as a waste management company.

It’s also a benefit to the biofuel company’s bottom line. For traditional biofuel makers relying on corn and other commercial crops, up to 90 percent of their operational costs come from those raw materials. By using whisky by-products, Celtic Renewables feedstocks are cost neutral and already partially processed.

Simmers says the company is currently working with Tullibardine whisky distillery in Blackford, Scotland, and the Bio Base Europe Pilot Plant in Ghent, Belgium, to scale-up its process to commercially viable levels. "We hope to commence the planning and development of our first commercial scale production plant in 2015," says Simmers.

With Europe’s mandate that 10 percent of all fuels sold by 2020 must be biofuels, preferably from waste and residue feedstocks, the timing may be right for Celtic Renewables.

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