Are bioplastics really so fantastic?
Biopolymers are often presented as an environmentally-friendly alternative to traditional plastics. However, they are not always as virtuous as we might think. Behind the name lurk diverse realities.
We take a closer look...
By Bertrand Beauté
Bio-... The prefix means "life" or relates to living things and therefore conjures in our heads the promise of living sustainably and on a healthy planet. Bioplastics have gained traction in recent years, replacing thin plastic bags (banned since 2016 in the European Union but still authorised in Switzerland) and offering a guilt-free substitute for certain packaging and everyday items, such as straws, water bottles, toys, pens and glasses frames.
Plastics Europe estimates that bio-attributed plastics now account for 1.5% of the world’s plastic production. The figure is relatively modest but is rising steadily. Global production capacities rose from 1.792 million tonnes in 2021 to 2.217 million tonnes in 2022, an increase of almost 25% in one year. And that’s not all. European Bioplastics, the European umbrella organisation representing the bioplastics industry, forecasts that supply will triple to reach 6.291 million tonnes in 2027, an average increase of 50% per year over five years!
The largest market for bioplastics remains packaging, which absorbed 48%, or 1 million tonnes, of production in 2022. Meanwhile, other fields of application are developing, such as the automotive sector, transport, agriculture, electrics and electronics.
The petroleum group Total aims to become a leader on the bioplastics market
This fast-growing demand is attracting not only a myriad of small, innovative companies, such as Origin Materials from the United States and the firms Avantium and Corbion from the Netherlands, but also industry giants. For example, the petro leum group Total aims to become a leader on the bioplastics market. In 2019, Total teamed up with Corbion to open a plant in Rayong, Thailand, that can produce 75,000 tonnes of bioplastics per year.
But is the "bio-" in bioplastic as natural and good for living organisms as the name suggests? The answer is not so simple. On paper, these materials look as though we should be able to use them guilt-free. But in reality, they do not always meet the claims. How so? The ambiguity comes from an overly broad definition. "First of all, we need to define what bioplastics are," says Pieter Busscher of Robeco. "The term covers two different types of materials: bio-based plastics and fossil fuel-derived plastics that are biodegradable or compostable."
Now, let’s get one thing straight: just because a plastic is plant-based does not mean it is biodegradable or compostable. Some are, some aren’t. In October 2021, the US giant Coca-Cola came out with its prototype PlantBottle, a PET plastic bottle made with 100% plant-based content (sugar from corn and forestry waste). If it ever hits the market, the bottle will offer the advantage of being renewable and probably reduce greenhouse gas emissions compared to fossil fuel-derived PET. But the fact that the bottle is plant-based will not change anything at the end of its life. Chemically, plant-based PET has the same structure as PET made from fossil fuels. That means it can be recycled, but if it is dumped, it will remain in the environment for several hundred years before breaking down.
In contrast, bioplastics made from fossil fuels are all biodegradable or compostable. But they have the disadvantage of being petroleum-based and therefore contributing to global warming. Various estimates set the share of the global oil supply that goes into producing plastic at between 4% and 8%.
European Bioplastics reports that 48.5% of all bioplastics produced in 2022 was not biodegradable. We could face another issue. As with biofuels, bioplastic production could take away land from food production. According to European Bioplastics, only 0.8 million hectares is currently used for bioplastic production, or 0.015% of the world’s farmland. But this figure could rise fast as the sector develops. For example, to produce one tonne of PLA bioplastic, 2.39 tonnes of corn, 0.37 hectares of land and 2,921 cubic metres of water are needed, based on figures from Plastic Atlas.
"It’s very dangerous to think that bioplastics offer the perfect solution," says Kokou Agbo-Bloua, Global Head of Macro Research at Société Générale. In fact, all experts agree that the important thing is to put the right material in the right place. "The origin of plastics is often used as a way of influencing consumer decisions, but we must be aware that a plant-based and/or biodegradable plastic is not necessarily less harmful to the environment," says Clément Maclou, portfolio manager at ODDO BHF. "The important thing is to further develop the classification and recycling chains for plastics at the end of their life cycle, to ensure that recyclable and/or biodegradable plastics do not end up in the same landfill as non-recyclable ones. Otherwise, there is little point in investing in biodegradable plastics."