Greening Steam

Low Carbon Distilling

Resource efficiency is now a fundamental aspect of every drinks brand. The first questions our branding colleagues ask of a new distiller are ‘will it be organic, will it be low carbon?’.

There comes a point in every distillery project when we have to make decisions about the supply of energy. Until very recently there was only one option which gave sufficient heat; a kerosene boiler, but not any more, now there are numerous ways to provide the heat for distilling, and there is no single solution because each distillery site is different.

The uncomfortable fact is that spirit making is an energy intensive process. A highly energy intensive process. Broadly speaking it takes around one litre of fuel oil to produce each litre of pure alcohol. And there is a lot of spirit made in Scotland, so whisky may be one of our great production successes, but it is one of our largest carbon producers also.

Finding alternatives to fossil fuels is therefore one of the most urgent yet exciting challenges which the industry has to face over the next few years. Every distiller will need to get their plan in place before carbon taxes arrive and hammer the production cost per litre. This is truly a time of positive change, driven by the demands of consumers and legislators. Yet Scotland is lucky to be a place rich in natural energy sources; wind and tides are abundant around the highlands and the islands where so many of the distilleries are based. We are in the perfect location to develop these technologies, to build up expertise and export our knowledge.

Every site we assess for a new distillery has its own unique environment, and that environment will present individual opportunities to generate power which will be different to every other site. We are approaching the time when it will be unacceptable to use fossil fuels. Production will become more complex and the solutions will be more nuanced. Never again will there be simple push-button power sources which give quick bursts of high carbon energy just to power steam distilling systems.

How big is the challenge then?

I’ve totted up the production capacity of the top 95 distilleries and using my broad 1:1 kerosene : spirit stat I tally that the industry uses just under 300 million litres of fuel oil each year. This means that Scotch whisky making produces around 200 tonnes of CO2 annually from the fuel source alone. This is a shocking environmental footprint for one of the countries’ leading industries, especially as this industry is cash rich and it trades on the unspoilt beauty of the landscape. The Scottish Government is well aware of this challenge and grant monies have been made available for low carbon energy centres which help to transition to low impact distilling.

What are the alternatives?

Distilling is currently powered by steam. Pot stills are heated by pipes which are effectively internal kettle elements, and the steam passing through them is supplied by boilers which are fired by kerosene or occasionally natural gas. Like all fossil fuel processes they are much easier to work with than the traditional ways they replaced. Huge calorific values are produced instantly.

An existing distiller can maintain the character of their spirit by using steam which is generated by low carbon fuels. There is one low-carbon fuel source which has been used in the industry for a number of years - biomass, in the form of chipped timber. This is the approach used at the Ardnamurchan and NcN’ean distilleries. Both use very local timber, taken from the land around the distilleries, so the ‘fuel miles’ are virtually zero. Instead of commercial forests being felled and exported the timber will be used locally over time, adding value to a low value crop.

Commercial monocrop woodland is a kind of green desert, so as it is used it can be re-planted with a more diverse range of trees more conducive to wildlife. Ideally quick growing copiced timber will be used, so there is a quickly replenished carbon cycle. This all sounds labour intensive doesn’t it? And yet labour intensive processes are a good thing for workers; more employment is created in remote areas, adding to the robustness of remote communities. The energy plan becomes an employment plan. So the land, local biodiversity and the neighbourhood are all made stronger by this approach. (And by the way oil trucks are taken off the road.)

This switch in the type of fuel requires only a small change to the process of distilling. It is still steam distilling at the end of the day. Yet this low-carbon win comes with compromise, biomass is by no means the optimum fuel source for distilling. Wood boilers like to smoulder, they burn continually, steadily and at relatively low temperatures. Biomass is ideal for heating a swimming pool, but it is less good for heating stills which like to burn very hot for short shifts. Getting a biomass boiler commissioned to supply heat for distilling is difficult, indeed there are distilleries which have installed expensive biomass boilers and they have hardly been used. This is itself a great under-use of resources, if boilers are balanced correctly they can work perfectly well.

It takes an expert like Neil Harrison of Reheat to properly balance a biomass boiler for the energy peaks associated with distilling. Although biomass boilers are costly to install they come with a relatively quick payback though – typically 10 years or less.

The small number of distilleries using biomass demonstrates the aforementioned fundamental rule of low carbon energy: The optimum choice of non-fossil fuel will be dependent upon the exact location of the building and the surrounding resources.

In the following post I will look at the emerging low-temperature alternatives to steam.