A new study has shown for the first time that waste cardboard can be used as an effective source of biomass fuel for large-scale power generation, offering a potential new domestic resource to support the UK’s renewable energy sector.
Engineers from the University of Nottingham have carried out the first comprehensive characterisation of cardboard as a fuel source and developed a new method to assess its composition. The research, published in the journal Biomass and Bioenergy, provides a practical tool for evaluating different grades of cardboard for use in energy production.
The study found that cardboard displays distinct physical and chemical properties compared with traditional biomass fuels.
These include lower carbon content, a reduced heating value and a high level of calcium carbonate fillers, particularly in printed grades.
Calcium carbonate is commonly added to cardboard to improve stiffness and optical qualities, but during combustion it forms ash that can reduce boiler performance.
To address this, the researchers developed a novel thermogravimetric technique to measure the calcium carbonate content of cardboard accurately. The method provides a practical and reliable way to assess fuel quality and suitability for large-scale combustion.
Biomass is currently the second largest contributor to renewable electricity generation in the UK, producing 31.1 terawatt-hours of power in 2022. Around 8.3 million tonnes of biomass are used each year for pulverised fuel combustion, accounting for 21% of the global wood pellet market. This supply is dominated by wood pellets and wood chips, followed by recycled and waste wood, while other biomass sources make up only around 1% of the total.
The majority of the UK’s wood pellet demand is met through imports, mainly from the United States and Canada, highlighting the need to identify additional domestic sources of biomass to strengthen energy security.
With an estimated 5.4 million tonnes of paper and cardboard packaging waste generated in the UK in 2021, cardboard represents a large and underutilised potential resource.
Although cardboard can usually be recycled between five and seven times, the fibres shorten and quality declines with each cycle. After this point, the material is typically composted or burned with other wastes in energy-from-waste plants.
The research suggests that instead of being treated solely as waste, end-of-life cardboard could play a valuable role as a consistent and locally available biomass fuel.
“Using our industry-standard facilities at the University, we have been able to show that cardboard is a viable option for use in large-scale energy production,” said Dr Orla Williams from the Department of Mechanical, Materials and Manufacturing Engineering.
“With our new methodology for analysing the exact composition of different types of cardboard, we can provide a tool that shows how effective it will be. The use of cardboard could provide a secure and stable pipeline for biomass fuel that will help the energy industry reach its sustainability goals.”
University study shows waste cardboard biomass is effective for power generation
