Well, not Scotch specifically, rather whisky manufacturing waste from Glenkinchie Distillery (The Edinburgh Malt). Whew, the culture dodged a bullet there. But it's also a good idea. Scotch is a $5.5 billion industry in Scotland and Edinburgh Napier hit on the idea that whisky by-products could be an excellent resource for developing biobutanol, a next-generation biofuel with 30% more output power than ethanol.
To understand how it works, you need a quick primer on whisky.
How to make Scotch whisky (though you can't call it that unless you are making it in Scotland)
Whisky is made from barley, yeast and water - nothing else is required but simple equipment. The barley is placed in tanks of water for 2 to 3 days and then germinates by being spread on the floor and turned 3 times a day to prevent mold. Part of the magic of great Scotch is knowing when to halt the germination, that takes some practice and is not part of a science discussion, but when it is done germinating you dry it in a kiln, those pagoda-shaped chimneys at every distillery.
Smoke from the fire in the kiln (they used to be peat-fueled but any number of fuels are used now, since presumably there would be no peat left in Scotland if they all used it in a $5 billion industry) rises through a wire mesh floor to dry out the barley, and the fuel matters because that smoke also adds to the flavor, and when it is dried, the barley is now 'malted'.
Once malted, the barley is mixed with hot water, and the starch in the barley converts to 'wort', which is transferred to a vat where yeast is added and the fermentation process converts that sugary wort into crude alcohol, called 'wash'.
The wash is placed in copper stills (whisky is distilled twice) where the alcohol is separated thanks to vaporization. From there, it is placed in oak casks for at least three years before it can be called Scotch whisky.
Here is a video guide by Brendan Coyle, distiller at High West Distillery in Salt Lake City, Utah, where presumably you have to learn to make your own, since they have no public bars:
Obviously there is a lot more to the craft of making my Macallan 25 (now at 37 years old!) than what I described but we are here to discuss the science, not the magic. There are two main by-products of the whisky production process; ‘pot ale’, which is the liquid left over from the copper stills and ‘draff’, which are the spent grains and those by-products served as the inspiration for the new biofuel because the industry annually produces 1.6 billion liters of pot ale and 187,000 tons of draff - that's a lot of cheap material to work with.
It's also a wiser environmental solution than the disastrous ethanol-from-corn solution encouraged by Al Gore and environmentalists in the U.S. since the late 1980s, which has driven up the price of corn and hurts poor people who have to pay more for food.
The biobutanol idea was inspired by the 100 year-old process created by Chaim Weizmann, a Jewish refugee chemist in Manchester (later instrumental in establishing the state of Israel and went on to become its first President) who developed the butanol fermentation as part of a program to produce rubber synthetically and was then also used in explosives manufacturing.
Professor Martin Tangney, Director of the Biofuel Research Centre at Edinburgh Napier University, is leading the research and says, “The EU has declared that biofuels should account for 10% of total fuel sales by 2020. We’re committed to finding new, innovative renewable energy sources. While some energy companies are growing crops specifically to generate biofuel, we are investigating excess materials such as whisky by-products to develop them. This is a more environmentally sustainable option and potentially offers new revenue on the back of one Scotland’s biggest industries. We’ve worked with some of the country’s leading whisky producers to develop the process.”
The University now plans to create a spin-off company to market the new fuel.
More on the Biofuel Research Center.