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Celtic Renewables: Transforming Waste into Green Chemicals 

Updated: Dec 18, 2025

CIRCULÉIRE members and team visiting Celtic Renewables on Sighthill Ct, Edinburgh on 10th November 2025.

Irish Manufacturing Research, in our capacity as the secretariat of CIRCULÉIRE in collaboration with Zero Waste Scotland, curated a multi-sectoral circular innovation exchange in September 2025 for our industry members which included multiple site visits to Scottish circularity pioneers.  

 

During this two day trip to Scotland we travelled to Celtic Renewables in Grangemouth, to see how a lab project has grown into Scotland’s first industrial biorefinery. What began in test tubes and 50ml flasks has scaled to 100,000-litre fermenters, operating 24/7 and shipping green chemicals to customers in pharma, cosmetics, and industry.  

 

What They Do  

Celtic Renewables adapts the ABE fermentation (Acetone-Butanol-Ethanol) process to use waste and by-products instead of food crops. This makes the process both more sustainable and more commercially viable.  

 

Key feedstocks include:  

 

  • Whisky by-products (pot ale, draff)  

  • Reject potatoes (unfit for sale or processing)  

  • Molasses from sugar production  

 

These are converted into bio-acetone, bio-butanol, and bioethanol — chemicals essential to modern life but currently made almost entirely from fossil fuels.  

 

From Research to Reality  

Celtic Renewables spun out of Edinburgh Napier University and was founded by Prof. Martin Tangney. Backed by a mix of private investors, government support, and crowdfunding, the company has grown from lab trials to full-scale demonstration. CEO Mark Simmers highlighted how difficult but vital financing was in getting the Grangemouth plant operational.  

 

Circular & Environmental Benefits  

  • Over 60% lower emissions compared with petrochemical equivalents  

  • Waste streams become valuable inputs, cutting transport miles and supporting farmers  

  • Potential to capture hydrogen and CO₂ by-products, further enhancing circularity  

  • Integration with anaerobic digestion could deliver even greater efficiency and value  

 

Why It Matters for Ireland? 

Celtic Renewables proves that by-products from distilling and agri-food can be transformed into high-value green chemicals at scale. Ireland, with its strong feedstock base and industrial clusters, is well positioned to adapt and replicate this model and explore industrial symbiosis opportunities particularly between the pharma and Agri-Food & Drinks Sector. 

  

Conclusion  

Celtic Renewables shows what happens when research, investment, and policy align: a proven process, real carbon savings, and tangible circular benefits. For Ireland, the opportunity is clear.  Our industries can seize similar models and lead in the shift to greener chemistry whilst creating jobs, cutting emissions and advancing the circular bioeconomy.  

 

IMR in its capacity as designer and lead of CIRCULÉIRE are delighted to represent our members as circular economy experts in DAFM’s National Bioeconomy Implementation Forum which explores how to scale circular bioeconomy in Ireland. 

 

 

🔗 Learn More 

 

(This report was co-designed and delivered by IMR in collaboration with the Irish Bioeconomy Foundation who are developing the National Bioeconomy Campus in Lisheen Mine). 




For a great example of a CIRCULÉIRE member pioneering biotech solutions, take a look at Niskus Biotech or our case studies on Irish agrifood companies pioneering the bioeconomy such as Meade Farm and Monaghan Mushrooms.  

 

 

 
 
 

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