Waste Not
Celtic Renewables Proving That Whisky Can Actually Help You Drive

Edinburgh-based start-up Celtic Renewables is turning waste matter from whisky production into a “next-generation biofuel” — biobutanol.

The whisky distillation process is tremendously wasteful; only ten percent of what comes from a distillery is consumed. The majority of the by-products — known as draff (a residue of grains: barley, rye, wheat and sometimes corn) and pot ale (residue leftover in casks) — are generally discarded, wasting a valuable resource and affecting the distillery’s bottom line. If the new process proves effective, using this renewed resource could result in a $90 million dollar value for the biofuel industry.

Celtic Renewables is using the tried and true 100-year-old fermentation method acetone butanol-ethanol (ABE). This uses the bacterium Clostridium acetobutylicum, which is derived from the starches used in whiskey production, to convert both the complex sugars, such as xylose and arabinose, and simple glucose into biofuels.

Independent malt whisky producer Tullibardine is the first distillery to partner with Celtic Renewables for conversion of its waste into fuel.

“The Scottish malt whisky industry is a ripe resource for developing biobutanol,” professor Martin Tangney, founder and president of Celtic Renewables and director of Napier University’s Biofuel Research Center, told the BBC. “The pot ale and draff can be converted into biofuel as a direct substitute for fossil-derived fuel, which would reduce oil consumption and CO2 emissions while providing energy security-particularly in the rural and remote homelands of the whisky industry.”

What about ethanol?

Biobutanol produces roughly 25% percent more energy by volume than its competitor, ethanol. In addition, biobutanol is easier to store because of its lower temperature to vaporize (flashpoint) and it can be blended into gasoline without additional modifications, unlike ethanol.

The fact that biobutanol is created from waste matter — unlike ethanol, which is generally made from fermenting crops such as corn that could be otherwise used for food — is another important distinction and testament to its viability as a biofuel. In even more good news, biobutanol production also creates two other valuable ingredients: bioacetane, currently being used in plastics and paints, and waste that can be used as high-quality grade animal feed.

Celtic Renewables and the Biofuel Research Center are building toward Scotland’s long-term zero-waste goal. Zero Waste Scotland is a government agency attempting to change the way Scotland manages its resources, aiming to run Scotland on purely renewable energy by 2020. This government-funded agency gave Celtic Renewables over $200,000 to expand. Tangney suggests his technology could help the EU reach its biofuel targets and account for 10% of fuel sales in seven years.

And this is only the beginning: Tagney says the process could similarly utilize waste from the production of other fermented products such as beer and wine.

In other sustainable spirits news, Bombay Sapphire announced in March that its new gin distillery in Hampshire, England became the first to achieve an “Outstanding” design-stage Building Research Establishment’s Environmental Assessment Method (BREEAM) accreditation. The company says the site, opening this fall, will emit 60 percent less carbon over its other distilleries by incorporating several technologies into its design, including photovoltaics, a biofuel boiler and a 6kW hydro-electric water wheel.


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