Are bioplastics a sustainable choice?
How a nice gesture from a friend got me thinking about plastic alternatives
By Julia Linz, PR and Communications Manager Green Alley Award
City life can be really tempting – especially on a hot summer’s day. I was meeting a friend for an event at one of the many piazzas in our city and he had the brilliant idea to buy me a drink. He went to one of these hip street coffee bikes catering the guests of the event and came back a few minutes later, proudly presenting a nice and cool iced coffee in a disposable plastic cup. My happiness about the drink was immediately marred by its packaging. Normally, to prevent waste, I only drink takeaway coffee if I have my reusable coffee cup with me! He noticed my hesitation and pointed to a small hint printed on the cup: “I am made of 100% biobased material and can fully biodegrade.”
The plastic dilemma
Indeed, my coffee cup consisted of the so-called bioplastic PLA (polylactides) made from cornflour. At least I had not wasted any non-regenerative resources like oil used for conventional plastics. But still, the question remained: In which bin do I put the bioplastic cup after finishing up my delicious iced coffee?
This dilemma got me thinking about the pros and cons of bioplastics and the question if they really are a sustainable choice. The answer depends on many factors, which are not easy to figure out for consumers. The term “bioplastic” itself suggests eco-friendliness and might easily mislead people. To get a clearer picture how “bio” or “green” bioplastics really are, two things have to be considered: First, what kind of resources are used to produce bioplastics and second, what happens to the bioplastic product when it becomes waste.
What are bioplastics?
European Bioplastics e.V. defines bioplastics as either biobased, biodegradable or featuring both properties. Biobased means that in contrast to common plastics, which are derived from petroleum or natural gas, bioplastics are fully or partly made from renewable biomass sources such as corn starch, cellulose, lactic acid or other sugar derivatives. Since biodegradability is a defining feature, even fossil based plastics can be labelled bioplastics if they biodegrade. On the other hand, there are also biobased bioplastics which are non-biodegradable or only partly biodegradable.
Based on this definition, three types of bioplastics can be identified: First, plastics that are both biobased and biodegradable (PLA, PHA or PBS), like the cup that was used for my iced coffee; second, plastics that are biobased or partly biobased but non-biodegradable (biobased PE, PP, or PET), for example the plant bottle by Coca Cola; third, plastics derived from fossil resources that can biodegrade (such as PBAT), which are often used for compostable plastic bags or as water resistant coatings for other materials.
Pros and cons of bioplastics
Getting the facts helped me to further elaborate on the pros and cons of bioplastics as a sustainable alternative to conventional plastics. One rather uncontroversial argument in favour of bioplastics definitely is the saving of fossil resources and thereby a reduction of all damaging side effects of the petroleum industry from air pollution to greenhouse gas emissions. In addition, the raw material is more sustainably sourced. In contrast to oil, the plant biomass is renewable and could be cultivated on an (at least) annual basis. Another pro is the biodegradability of most of the bioplastic types. Whereas bioplastics could naturally break down in the environment and convert into natural substances, petroleum plastics will only break down into smaller and smaller pieces until they turn into the widely feared microplastic polluting our oceans and our beaches. Some bioplastics could even be put into your garden compost – a great invention, isn’t it!?
Unfortunately, it is not that easy. Reminiscing about the moment I finished my iced coffee in a supposedly biodegradable PLA cup, I asked myself: How will I know anyway (in case there is no information printed on the product) if the material is bio-based or petroleum based, if it biodegrades or not and, if it does, how long it will take to break down into natural substances? Should I take it home with me to put it into the biowaste or just leave it at the side of the road and it will biodegrade and be restored to nature in a few days? And what happens to the cup if I simply put it into the general city bin? An overwhelming lack of information just seemed to paralyse any sustainable decision making.
At that time I did not know that PLA only breaks down in a high-temperature industrial composting facility and not in an average household compost bin. And I did not know either that there is no recycling infrastructure in place to deal with bioplastic materials in a proper way – not anywhere in the world! For today’s industrial composting facilities bioplastics simply are a contamination risk. Recycling bin or residual waste – no matter where you put them, bioplastics will be burned instead of recycled.
But what is the solution then?
Are bioplastics the solution to our plastic problem?
A throwaway bioplastic cup that cannot be recycled is definitely not the answer to our plastic problem. Although it seems to be far from being THE sustainable alternative to any petroleum based plastic, bioplastics can still be a sustainable choice if applied in a sensible way! Decisive is WHEN we use it as alternative.
Even though biodegradable bioplastics for home composting seem to be the most sustainable option (if everyone had a garden), less packaging and less material is still the best choice. This means, we have to reduce the overall demand for plastics, since even bio-based materials do not come without costs: Produced in huge amounts, they could lead to deforestation in order to gain more land to grow crops, facilitate monoculture and counterbalance their benefits due to the negative impacts of fertilizer and pesticides that might be needed.
As a first step, my general recommendation would be to reduce the use of plastics and plastic packaging whenever possible. Alternatives like reusable coffee cups, bringing your own shopping bag or buying fresh fruits and vegetables directly from the producer on the weekly market, are easily integrated in your daily routine. Some supermarkets even allow you to bring your own box to put your cheese or meat in it.
In case packaging is necessary, producers and manufacturers should carefully gauge what material and format they use for which application, considering the carbon footprint, but also the current recycling infrastructure as well as the public understanding of plastics and bioplastics. For example, a reasonable area of application for compostable bioplastics would be the food and foodservice industry, because then potential food leftovers could be organically recycled with the packaging.
In the meantime, politics and industry have to find optimal recycling solutions for bioplastics, create a better infrastructure or even cradle-to-cradle solutions for these materials.
What can the Green Alley Award contribute?
After striking this rather mixed balance there is still good news: This year’s Green Alley Award startups have come up with several alternatives for plastics and plastic packaging and we hope to present the most promising idea(s) as soon as our finalists are nominated. So stay tuned!
Read more on how to get out of the plastic trap!
Want to knwo what Suvi Haimi, jury member for the Green Alley Award 2018, thinks about bioplastics? Read here!