Measuring the energy content of waste
13 Mar 2013
Cranfield, UK – Cranfield University is developing an interesting new approach for calculating the potential renewable energy derived from waste material, prior to incineration. The technique could save time and money for the energy and waste industries.
The Government’s Renewable Obligation Certificates (ROCs) scheme places an obligation on UK electricity suppliers to demonstrate the biomass content, or fraction, of mixed fuels and offers incentives for sourcing an increasing proportion of the electricity they supply to customers from renewable sources.
Calculating the renewable content of waste conventionally involves manual sorting of waste into individual components, which is time-consuming and carries issues regarding labour costs and health and safety concerns.
Another approach involves analysing of the flue gas using specialist equipment for carbon dating. However, this is often very costly, and can only be calculated retrospectively.
Cranfield’s new method uses an image and microwave analysis tool. When placed above a conveyor belt in a waste treatment facility, it is able to accurately determine the composition of a mixed waste material and subsequently calculate how much renewable energy is derived from each individual component in the waste stream.
“The system enables greater operator control over the fuels, allowing for blending to optimise the biogenic (renewable) content and the overall calorific value, or energy released on combustion,” said Dr Stuart Wagland, a lecturer in renewable energy from waste at Cranfield.
As well as saving time and money for the waste industry, the tool will enable energy suppliers to accurately prove the amount of biogenic material - waste made up of materials produced by living organisms or biological processes such as paper, certain textiles and food waste - in each load of mixed waste materials that will produce renewable energy through combustion.
It is thought that some 200m tonnes of waste produced each year in England alone could be converted to energy with the potential to supply up to 4% of the UK’s electricity and water heating needs.
The research has attracted interest in the private sector, and work is now being planned, in collaboration with the National Physical Laboratory, to further develop the tools and test them in a range of waste handling facilities.
