Beer by-products are set to be converted into renewable fuel following a university research breakthrough.

Left-over barley can be changed into carbon and used to heat homes in winter or as charcoal for summer barbecues, test results showed. It could also provide water filtration in developing countries.

Breweries in the EU throw out around 3.4 million tons of unspent grain every year, weighing the equivalent of 500,000 elephants.

Using one kilogramme of the grain, Dr Ahmed Osman from the School of Chemistry and Chemical Engineering at Queen’s University Belfast has been able to create enough activated carbon to spread across 100 football pitches.

He said: “There are only a few steps in our low cost and novel approach – drying the grain out and a two-stage chemical and heat treatment using phosphoric acid and then a potassium hydroxide wash, both of which are very low cost chemical solutions.

“This then leaves us with activated carbon and carbon nanotubes – high value materials which are very much in demand.”

Liquid forms of carbon are normally shipped to the UK from the Middle East, and solid biocarbon in the form of wood pellets is shipped from the US and elsewhere.

Dr Osman said: “Using this new technique, we can utilise more locally produced resources, reduce emissions linked with the agriculture sector, and we are also creating a high-value product.

“Across the globe there is a real demand for carbon as it is used to create fuel for households, parts for water filters and charcoal for barbecues.

“If we are able to take something that would otherwise be a waste and turn it into a useful biofuel, it can only be a good thing for our planet. It could really help to solve global waste and energy problems.”

He said it was a “prime example” of the circular economy, by taking waste food by-products and creating a high-value product.

“It has benefits to the environment and society through economic and social opportunities.”

The project was an international collaboration between Queen’s University Belfast, South West College and Sultan Qaboos University in Oman.

The results have been published in the Journal of Chemical Technology and Biotechnology.

Dr Osman is hoping to explore opportunities for the commercialisation of the method in creating activated carbon and carbon nanotubes.

Queen’s work on biofuels from waste will be featured in a major conference, Engineering The Energy Transition from February 26-28 2020 in Belfast.