Sustainability

Swansea University researchers unlock plastic waste car fuel potential

Researchers at the University of Swansea's chemistry department have announced that they have successfully been able to turn unwanted plastic into hydrogen, which could potentially be used to fuel cars.

The global plastic pollution problem is by now firmly fixed in the public news agenda, with the shocking figures and statistics relating to plastic waste now increasingly common knowledge – around eight million tonnes of plastic waste enter our oceans every year.

Dr Moritz Kuehnel, one of the leading researchers on the project, explained that light-absorbing material is added to the plastic, which is then placed in an alkaline solution before being exposed to sunlight, or a solar simulator lamp, to generate hydrogen, with the remaining plastic then breaking down into smaller, organic pieces.Researchers at Swansea University unlock plastic waste car fuel potential

Dr Kuehnel went on to say that any kind of plastic can be used and does not require cleaning beforehand, so could be less expensive than recycling, which often requires the collected plastic to be cleaned thoroughly and can encounter problems due to the variety of different plastic polymers used in products.

He said: “There’s a lot of plastic used every year – billions of tonnes – and only a fraction of it is being recycled. We are trying to find a use for what is not being recycled. Even if you do recycle it, it needs to be very pure – so only PET, nothing else mixed with it… and it has to be clean.”

However, it is claimed that by using the light-absorbing method to break down plastic into hydrogen, money can be saved as the process does not require the plastic waste to be clean. Kuehnel said: “Even if there is food or a bit of grease from the margarine tub, it doesn’t stop the reaction, it makes it better.”

Furthermore, the remaining pieces of plastic left behind after the generation of hydrogen leave behind chemicals that can then be used to make new plastic. Kuehnel added: “We don’t make a full new plastic, we use just half of the material to make new plastic and the rest can be recycled – a clean, clear water bottle out of plastic.”

The work is being carried out in a lab in Cambridge, funded through the Engineering and Physical Sciences Research Council and an Austrian petrochemical company. Though the initial results are promising, it may be a few years before the method is able to be rolled out on an industrial scale.

Despite the seemingly positive use of waste plastics in fuel, the idea is certainly controversial. In May this year, an EU proposal for a revised Renewable Energy Directive listed ‘waste-based fossil fuels’ as materials that could be converted into energy, including waste plastic materials that cannot be recycled because they contain too many ‘impurities’.

Major organisations, such as Zero Waste Europe and Friends of the Earth Europe, voiced objections at the time to the proposal, alongside national groups in Ireland, Estonia, Greece, Bulgaria, Germany, the UK and Portugal wrote a joint letter to European Commissioner for the Environment expressing ‘deep concern’ over the proposal. They argued that using non- recyclable plastics would be ‘equivalent to the use of fossil fuels.

A spokesperson from Zero Waste Europe, Janek Vahk, said: “An important element in moving to a circular economy is to make plastics easier to recycle. If plastics that are currently difficult to recycle are turned into fuel, the incentive to redesign is lost. Instead there will be a lock-in into an inferior technology that produces energy from fossil fuels.”

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