​Hazelnuts are undoubtedly delicious and a favourite with cooks everywhere, but researchers now believe that their shells could also be a great source of potential renewable energy.

Chinese scientists have discovered that the shells of hazelnuts contain all of the ingredients needed for high-quality biomass, which is needed to create the next wave of biofuels. Hazelnut shells have been shown to perform well under pyrolysis conditions - a process that separates biomass ingredients under heat to make efficient bio-oils.

The shells produce wood vinegar and tar fraction, both of which have a range of current valuable applications, from animal feed additives and fertiliser to industrial fuels.

This means that hazelnut shells could be used commercially in future to produce these kinds of valuable by-products. Wood vinegar was the highest yield from the process, producing a 31% weight at 700 C. The yield was attractive enough for the process to have potential commercial applications, helping to recycle wasted shells and to extract vital renewable energy from existing processes.

Biomass has been a more controversial renewable energy product because it requires organic inputs to produce clean energy. For many, it is seen as a bridging technology to 'cleaner' biofuels such as wind and solar power because it produces carbon dioxide when it is burned.

However, as hazelnut shells are already produced in vast quantities for food purposes, there would be value in making use of the shells, particularly if they can be further refined to produce bio-oil via pyrolysis for commercial, agricultural and industrial applications rather than simply being wasted.

The researchers' findings have been published in the Journal of Renewable and Sustainable Energy, and further studies will be commissioned to see how commercially viable these processes could be.