Combined Heat and Power Biomass Plant

For many years Scottish whisky producers have explored ways to maximize the use of organic by-products from the distilling process, seeking to minimize overall waste, maximize operational efficiency and contribute to new feedstocks or end products. Thanks to evolving bioenergy technologies and beneficial reuse solutions, food and beverage companies are addressing numerous overlapping business and sustainability challenges.

Rothes CoRDe is a combined heat and power (CHP) biomass plant in Rothes, Scotland, that brings in spent malted barley from numerous local whisky producers, known as draff, the distillation residue from the distilling process, known as pot ale, and the water washings from the whisky production process.

The CHP plant treats the draff and pot ale by mechanically pressing the draff to remove surface moisture, drying it using steam extracted from a steam turbine, and then using the pressed and dried draff as a fuel to fire a biomass boiler to produce steam. The steam then generates electricity from a steam turbine, with steam being extracted from the turbine for drying the draff fuel and for evaporating the pot ale to produce concentrated pot ale syrup, which is marketed as a medium-protein animal feed. The CHP plant produces approximately 8 MW gross electricity and exports approximately 6.7 MW net to the distribution network along with 40,000 TPA of animal feed.

Leveraging deep expertise in distillation and refining processes, Lummus Consultants has been the independent engineer for the project since initial conception. The scope of work included verification of the original designs for lenders, monitoring construction, witnessing performance tests, and annual status reviews since commissioning in 2013. More recent work has involved assessing the ability to export additional heat and power from CoRDe by private wire to new industries in the plant’s vicinity. Over the project’s many years, our efforts have assisted the various stakeholders in financing and improvements of the facility.