Costs saved by turning distillery co-products into renewable energy


The whisky heritage of the beautiful Scottish Highlands is being preserved, as Diageo leads the way by converting its distillery co-products into renewable energy.  The Diageo distillery at Dailuaine was first to use Clearfleau’s anaerobic digestion (AD) technology, becoming operational in 2013.  Since August 2015 the site at Glendullan has been using the same system to manage distillery co-products.
Diageo is committed to efficient, sustainable production. This includes a global target to reduce the water it uses by 50% and to return 100% of it safely to the environment. 
Diageo has to replace outdated effluent treatment plants at its Scottish distilleries to handle larger volumes of co-products.  As with other food and beverage producers, today’s regulatory standards require a more sustainable approach.  Distilleries, often located in places of natural beauty, require bio-energy solutions that are fully integrated with the local environment.
The Glendullan bio-energy plant optimises energy output from the co-products from the distillation process.  The project involved close collaboration between Clearfleau’s in-house design, installation and commissioning engineers, their counterparts from Diageo and an extended supply chain.  
The main engineering challenge was developing a bio-energy plant able to handle higher-strength materials such as pot ale alongside other more dilute distillery co-products.  The on-site process uses bacteria to convert liquid co-products to valuable renewable energy for the distillation process.
The Glendullan bio-energy plant is taking co-products from several sites in and near Dufftown:
Generating over 2 million m3 of biogasDelivering 8,000 MW hours of thermal energyTurning 1,000m3 of co-products into 1MW per hourSaving over 1,000 tonnes  of carbon each yearCutting over 15 truck journeys  every day
Clearfleau’s innovative liquid AD system reduces organic load from distillery co-products by 95%.  This minimises additional treatment required for discharge of cleansed water to the River Fiddich.    Bacteria produce biogas, supplying renewable heat or power for the distillation process.  The result, a cost-effective closed loop where all Diageo’s process residues are recycled and re-used.
Clearfleau’s on-site AD technology converts the unwanted co-products into valuable biogas that generates renewable heat for use in the distillation process while reducing a major overhead, the co-product disposal cost.  By reducing costs and benefiting the local environment, Diageo is setting an example to British food and beverage companies (including other distillery sites).  
Following the 2013 completion of an initial high-rate digestion facility at the Dailuaine malt distillery, Diageo commissioned Clearfleau to build a second facility.  The Glendullan plant is very similar and receives feedstock from other distilleries in the Dufftown area. Some is fed to the plant in a recently completed pipeline reducing local truck movements. 
Glendullan’s bio-energy facility generates 2 million m3 of biogas per year – producing about 8,000MW hours of thermal energy for the distillery, based on processing up to 1,000m3 of distillery co-products on a daily basis.   There are just two other outputs – clean water for river discharge and bio-solids suited for land application. 
Diageo’s savings on energy and treatment costs, plus Government incentives for renewable energy generated, ensure an attractive payback for the AD plant.  Key benefits for Diageo include:
Reduced treatment costsLower carbon emissionsDecreased site energy costsRevenue from renewable incentivesMore sustainable production and improved CSR
By generating bio-energy from distillery co-products, Diageo is showing how one of Scotland’s most traditional industries can deliver significant cost savings and environmental benefits. The two bio-energy facilities, on Speyside malt distilleries, are examples of how the beverage sector can use this technology, supporting commercial and environmental goals with an attractive payback. 
On-site AD facilitates a more sustainable approach to manufacturing.  Efficient treatment means fewer vehicle journeys, less handling of residues, lower energy use and lower carbon emissions. In the distillery sector on-site AD is demonstrating a practical example of the circular economy.  

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