Explosive Start to Whisky-waste Biofuel Revolution
Celtic Renewables recently won the ‘Most Innovative European Biotech SME’ award for its leading-edge work. Launched in 2012 as an offshoot of Napier University’s Biofuel Research Centre, the company quickly formed partnerships with Tullibardine distillery and BioBase Europe Pilot Plant (BBEPP).
The work of Professor Martin Tangney – founder of Celtic Renewables – and his team builds upon a process known as acetone–butanol–ethanol (ABE) fermentation first developed by biochemist (and, incidentally, Israel’s first President) Chaim Weizmann. Acetone is used in the manufacture of cordite; Weizmann’s breakthrough provided the British munitions industry with the acetone it needed to make the smokeless propellant during World War I.
(Even more incidentally, the main ingredient of this particular type of cordite was collodion – a flammable, gel-like substance originally used in wet plate photography. It also has medical uses, and Thomas Stoltz Harvey secretly preserved Einstein’s brain in blocks of the stuff.)
Ethanol and butanol are both capable of powering internal combustion engines, but butanol is the more efficient of the two fuels, at up to 92% of the Btu output of gasoline compared to ethanol’s 70%. Chemically, butanol is more like gasoline.
Being conveniently rich in proteins, starches and sugars, the whisky-making by-products known as draff and pot ale make ideal feedstock biomass for the bio-butanol production process. The anaerobic (without oxygen) fermentation used to create bio-butanol relies on the ability of the Clostridium acetobutylicum bacteria to metabolise sugars to produce long hydrocarbon-chain alcohols.
OK. That’s the hype, some chemistry and a fair bit of digression. ‘Biofuel’ sounds satisfyingly ‘green’, but when you think about it, oil is also a biofuel. Most oil is simply deposits of long-dead biological microorganisms accidentally ‘sequestered’ beneath layers of lithified sediment. As far as we know, this process takes aeons, so there’s no obvious way to make more crude oil quickly. If we could make it quickly, oil would be a renewable energy source. Of course, burning oil in engines as gasoline or diesel also releases its naturally sequestered CO2 and generates airborne particulate pollutants. Not clever.
Making biofuels tampers heavily with the natural order in a way that’s useful to humans. Tangney’s sealed vats of bacteria, draff and pot ale are a wonderful instant ‘broth’ equivalent of nature’s micro organism Marmite and primordial soup. In theory, bio-butanol made from whisky waste is renewable (as long as people keep drinking whisky) and ‘sustainable’ (as long as people keep drinking whisky). Actually, the same process works with other bio-waste, including waste from beer-making and from certain types of paper production. The fuel can be used in unmodified vehicles, it burns a little cleaner than gasoline and is safer to handle.
As with all biofuels, however, we’re still burning stuff to make stuff go. And we’re still generating particulates and releasing CO2. That isn’t sustainable. Draff and pot ale may be classed as ‘waste’ products (although they have long been used as animal feed), but the barley (a land- and fertiliser-use intensive crop) had to be grown in the first place. Using whisky waste is certainly more sustainable than burning down forests (releasing sequestered carbon), digging up soil and roots (releasing sequestered carbon, nitrogen and phosphorus) and using up scarce water resources to grow biomass crops for biofuels. And there’s a lot of it available – some half a million metric tons of spent-grain draff and around 2 billion litres of pot ale annually.
The world does love a good whisky story, doesn’t it? The corporate behemoths that have swallowed most of Scotland’s unique, independent distilleries now have an excellent environmental ‘greening’ script to go with their nostalgic, romanticised narrative.
But I certainly don’t mean to be cynical about the work of Celtic Renewables and other innovative, science-led companies tinkering fabulously with consumer society’s discarded biochemistry set, doggedly proving that where there’s bio-gunge there’s bio-brass.
My opinion as a futurist person? Bio-waste bio-butanol still falls somewhat short of ‘sustainable’ and still seems a bit, well… dirty. I say bring on the hydrogen fuel cells. Bring on the space-based solar panel arrays. Bring on the micro-suns, the gold cans, the tokamaks. ‘Toroidal plasma fusion reactor’ has a nice ring to it, don’t you think? Cheers.