Converting waste into fuel
University of Exeter researcher Kev Hughes has been exploring the true cost-effectiveness of anaerobic digestion (AD) - the process of converting waste material into biogas that can then be burned to generate heat or electricity. Kev is developing an AD-based renewable energy technology suitable to the specific needs of Cornwall’s farming sector.
Supported by the ESF (European Social Fund) Convergence Programme, Kev has been working with the Cornwall Agri-Food Council(CAC) to help develop smaller-scale AD applications that can be easily installed and operated on farms with a view to improving agricultural business, helping the environment and boosting the Cornish economy.
Anaerobic digestion is a proven technology. It saves energy, cuts greenhouse gases and even produces fertiliser but most AD plants are complicated and costly.
Kev identified the key factors that affect the financial viability of constructing, running and financing an AD plant on a dairy farm. From this he researched ways of influencing those factors without disrupting the dairy operation, carrying out extensive rheological analysis of a broad range of cow slurries of various solids content and consistencies using variables such as temperature and mixing intensity.
David Rodda, Coordinator for Cornwall Agri-food Council, said: “We’ve always struggled to make the economics of anaerobic digestion stack up. This collaboration allowed us to take a different look at it – and if we can crack it on a small-farm scale it will have huge potential for roll-out at hundreds of farms across Cornwall. The research to date is very promising as it has focussed research on maximising the gas yield from farm slurries and surplus crops alone, rather that combining this feedstock with food waste and energy crops.”
This project has enabled Kev to not only build links with the local agricultural industry but also to set up his own business - ADvise Ltd, which is an independent provider of AD research, development, analysis and advice on farm-scale anaerobic digestion.
Kev said: “I established the company to further the research and development of a number of AD solutions post my PhD. ADvise is based locally in Penryn and provides guest lecture support to the University as well as industry placements for renewable energy students. It is currently seeking research partners to provide the UK with a financially viable AD solution for dairy farms based on the outcomes of the PhD and has produced two designs of varying complexity and cost that it is about to patent.”
An AD solution would allow Cornwall’s farmers to reduce their dependence on energy from the grid and fossil fuels and operate their businesses more sustainably. This would in turn help CAC pursue its long-term strategies regarding key concerns such as carbon reduction, water and energy security and Cornwall’s position as an exemplar of excellence for the UK’s agri-food industry.