Model for Climate-Neutral Plastics Claims to Achieve Circularity and Affordability
It sounds too good to be true — and you know what they say about that — but researchers claim that by judiciously applying a trio of existing technologies, plastics can be produced using less energy at equivalent, or even less cost than alternative technologies. A study published in the latest issue of Science makes the case.
A trans-Atlantic research team from ETH Zurich in Switzerland, RWTH Aachen University in Germany, and the University of California, Santa Barbara, has created a computational model of global plastic production and disposal. The model reportedly shows that it is economically feasible to produce plastics that have a net-zero greenhouse gas emissions balance over their life cycle by combining three known technologies: Plastic recycling and plastic production from biomass and from CO2 via carbon capture and utilization. Through an optimal combination of these production technologies and accelerated use of recycled plastics, energy consumption can be reduced by 34 to 53% compared with current fossil-fuel-based methods. By 2050, the cost of global plastic production could be reduced by as much as $288 billion per year, according to the research.
Carbon capture technology is seen by some as an indispensable tool in limiting carbon emissions by polluting industries, but the market is in its infancy. Climeworks, a Swiss company founded by two ETH Zurich graduates, believes it has the goods to make it more widely available. The startup made a splash last month, when it launched Orca in Iceland, reportedly the world’s largest direct air capture and storage plant. ON Power, the Icelandic geothermal energy provider, supplies clean renewable energy to power the Orca plant, and Climeworks’ partner Carbfix, which has expertise in rapid underground mineralization, mixes the air-captured CO₂ with water and pumps it deep underground, where it is trapped in stone through a natural mineralization process that takes under two years. Climeworks claims that Orca is a first step to achieving megaton removal capacity by the second part of this decade, based on its scalable direct air-capture technology.
Captured carbon is already being used to produce polymers. For example, Covestro has been using CO2 as a raw material to produce chemical building blocks for high-quality plastics since 2016, notes the EU Circular Economy Platform. Polyurethane flexible foams used for mattresses and furniture, commercialized under the cardyon name, contain up to 20% CO2, and have comparable or even better properties than the conventional polymers made of crude oil.
BBC Earth has reported on research at Swansea University in the United Kingdom to produce ethylene, which goes into about half of all plastics used globally, from carbon dioxide. Professor Enrico Andreoli of the Energy Safety Research Institute at the university and his team are working to develop copper-containing catalysts that allow for the creation of ethylene by combining carbon dioxide with water and electricity, writes BBC Earth. However, it would take some 20 years to produce polyethylene on a commercially viable scale using this method, note the researchers.
So, while achievable, the use of carbon capture technology to produce plastics carries a cost. Bringing down that cost is one of the caveats cited by the trans-Atlantic research team before their computational model can be translated into reality. The other necessary conditions are making biomass and renewable electricity also available at low cost; making extraction and supply of petroleum more expensive; and providing incentives for investment in recycling. “The lower energy demand may seem counterintuitive, but it results from the amount of energy that recycling saves over the entire life cycle,” explained André Bardow, formerly of RWTH Aachen University and now Professor of Energy and Process Systems Engineering at ETH Zurich, who led this research.
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