Scientists at the UK’s Swansea University have hatched a means of chemically transforming hard-to-recycle plastics into conductive materials that could be engineered into low-loss, high-voltage power lines, sharply improving the economics of long-distance electricity transmission from wind and solar plants.
By breaking down so-called ‘black plastic’ – commonly used in packaging for ready-meals and fruit and vegetables in supermarkets – into its carbon, hydrogen and oxygen elements, the researchers found they could then re-bond them in different arrangements to create carbon nanotubes, which can be used to make flexible energy-generating materials.
“The research is significant as carbon nanotubes can be used to solve the problem of electricity cables overheating and failing, which is responsible for about 8% of electricity is lost in transmission and distribution globally,” said Alvin Orbaek White, Sêr Cymru II fellow at the university’s Energy Safety Research Institute, who led the study.
“Many long-range cables, which are made of metals, can’t operate at full capacity because they would overheat and melt. This presents a real problem for a renewable energy future using wind or solar, because the best sites are far from where people live.”
He told Recharge: “Though there is no such thing in nature as ‘zero-loss’, any losses that will occur [in a carbon nanotube engineered powerline] would be far lower than present materials. The best estimates suggest a cable of ‘armchair single-walled nanotubes’ could transmit hundreds, or even thousands of miles with just miniscule loss, due to a process called ballistic electron transport.”
The structure of a carbon nanotube, which White describes as looking “like a piece of chicken wire wrapped into a cylinder”, allows it to conduct both heat and electricity: “These two different forms of energy are each very important to control and use in the right quantities, depending on your needs.”
Nanotubes are currently used to make a range of products, from conductive films for touchscreen displays, through flexible electronics fabrics that generate energy, to antennas for 5G networks, he pointed out, adding “NASA has used them to prevent electric shocks on the Juno spacecraft”.
During the Swansea University study, the researchers removed the carbon from different black plastics, among the hardest to recycle using conventional technology, and then used it in atomic form to construct nanotubes that could transmit electricity to a light bulb.
White’s team now plan to design high-purity carbon electrical cables using waste plastic with improved electrical performance and higher output, with an eye on large-scale deployment “in the next three years”.
“Large-scale deployment could entail a few things,” he said. “On the largest scale we are positioning ourselves for global grid integration. This could possibly even entail the replacement of copper-aluminium wires in the future.”