Did you know that carbon capture has been happening in Edinburgh for 30 years?
Carbon dioxide is a by-product in the production of whisky, resulting when yeast ferments wheat grain, or malted barley, to make alcohol. It’s also an important ingredient in fizzy drinks – and one Scottish distillery spotted an opportunity to join these two things up back in the late 1980s.
The North British Distillery, in Gorgie, has long been capturing the carbon dioxide from fermentation, purifying it to a high standard of food safety, and selling it for other food and drink manufacturers to use.
There are many different ways to capture carbon dioxide, and the technology is changing and improving all the time, so SCCS was keen to find out how the North British Distillery does it. Their Environment Manager, Owen Foster, kindly invited us to visit the site where we found out that carbon capture is just the beginning of the story of the distillery’s work to reduce its environmental impact. As well as capturing 4 tonnes of CO2 per day, it produces animal feed from syrup by product and from the ‘draff’ leftover after fermentation and distillation. The site also uses anaerobic digestion to produce biogas, which it uses to provide additional heat and power to the site (and heat to a nearby school), and has made its processes more energy- and water-efficient.
The carbon capture process at this site is relatively simple, because the off gas from fermentation is already very pure in CO2. The process is not about enhancing CO2 concentration, but more about removing impurities. That involves a number of washing stages to remove water and impurities from the gas given off during fermentation, before it is compressed, stored, and eventually transported by road. It was fascinating to see how the kit is integrated into the whisky-making process, and on a city-centre site – not only is the distillery resource-efficient, it is space-efficient too.
The North British Distillery is a large operation – it produces about 1.5 million litres of spirit each week – and it is lucky that its Edinburgh location means it can easily find customers for both CO2 and animal feed. It’s a far cry from the stereotype of the small highland distillery, but it’s not the only large distiller in Scotland: there are several other large producers of grain whisky that might want to consider capturing their carbon dioxide, whether for use in other products, or for permanent storage far below the North Sea. Could Scotland’s national drink help kick-start a Scottish CCS industry?