A process that turns mixed plastic waste into high-purity hydrogen could address two persistent industrial challenges: hard-to-recycle packaging and the cost and resource demands of low-carbon hydrogen. Researchers at UCLA Samueli School of Engineering and Ewha Womans University in South Korea report that their Alkaline Thermal Treatment method converts common plastics in a single reactor without sorting them first.
One process for three common plastics
The method uses heat to process polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP). The researchers say it produces high-purity hydrogen with zero carbon emissions. Their findings were published in PNAS this month.
That combination could matter for both waste management and hydrogen supply. Plastic sorting adds complexity to recycling, while hydrogen production methods carry different costs and emissions depending on their inputs. The reported process links the two problems by using plastic waste as a feedstock. The source, however, provides no production cost, output rate or operating data, so its commercial economics remain unclear.
“We are solving two urgent global problems at the same time,” Ah-Hyung “Alissa” Park, a professor of chemical and biomolecular engineering at UCLA and co-corresponding author, told Interesting Engineering. Park said plastic waste is accumulating while clean hydrogen is needed for decarbonization, describing the technology as creative and scalable.
Hydrogen’s climate case depends on production
Hydrogen can supply high-temperature heat for industrial processes such as steelmaking and shipping fuel systems. When used, it produces water vapor, but that end-use benefit doesn’t determine its full climate impact: production does. Most hydrogen used in industry is gray hydrogen, made from fossil fuels. Green hydrogen is produced with renewable energy, but it can be costly and demands electricity that may have other uses.
A 2022 report from the International Renewable Energy Agency cautioned against indiscriminate hydrogen use. IRENA argued that dedicated renewable power for hydrogen could be diverted from other needs, and that extensive reliance on green hydrogen may not align with the requirements of a decarbonized economy. The economics and energy inputs therefore matter as much as the fuel’s emissions at the point of use.
Producing hydrogen from waste could change that calculation if the process proves efficient and affordable at scale. The UCLA and Ewha results offer a research pathway, but the information available so far doesn’t establish its cost or readiness for commercial deployment.
Other waste-based routes draw attention
The plastic work follows research in China that converted sugars from agricultural residues, including wheat stalks, into hydrogen. The source reports a production cost of $1.54 per kilogram, or about $0.70 per pound, and says the method could compete with gray hydrogen. That figure offers a point of comparison for waste-based production, though it doesn’t establish the economics of the plastic treatment process.
These approaches are emerging after years of slow delivery from the broader green hydrogen project pipeline. A study tracking 190 projects found that only 7% of announced global capacity was completed on schedule in 2023. The gap between project announcements and delivery has weighed on expectations for hydrogen’s near-term role.
Interest has since revived amid volatile oil markets and renewed attention to energy security. China, Europe and the United States are pursuing hydrogen investment, while research teams look for production routes that use less expensive or otherwise discarded inputs.
Scale and cost will decide the significance
The UCLA and Ewha team’s central claim is practical: one reactor can process several widely used plastics without presorting them and yield high-purity hydrogen. The next question is whether the process can maintain that performance beyond the reported research setting, with costs and energy requirements that make sense for industrial users.
If those measures hold up, plastic-derived hydrogen could add a waste feedstock to the mix of low-carbon production options. For now, the finding is a promising technical result; its market significance will depend on operating data and the economics of scaling it.