Carlsberg, Coca-Cola and Danone have recently announced their backing for a project which would make plastic from plants rather than fossil fuels. On paper, anything which reduces our dependency on fossil fuels sounds like it can only be a good thing, but will these ‘bioplastics’ really solve the problem of plastic pollution?

A conventional plastic bottle will take anything up to several hundred years to break down, but these new bottles would be made from plant sugars that would decompose in one year in a composter and take a few years to break down if left under normal conditions outdoors.

If we want to tackle our plastic pollution problem for good then the only logical step is to drastically reduce the volume of plastic we are consuming in our everyday lives. However, with projects like this plant-based bottle gaining momentum, there is now a growing concern that we are rushing to replace fossil fuel based plastics with alternatives which might not be as environmentally friendly as we first thought.

What are bioplastics?

The term ‘bioplastics’ is used to describe plastics which are bio-based, biodegradable or both. These types of plastic are based partly or fully on biomass resources such as sugar or starch. When it comes to bioplastics we cannot apply the same one size fits all approach as there are multiple different types of bioplastics which all break down under different conditions at various timescales. 

In the past few years, there has been a big rise in companies marketing products to consumers which are labelled as either bioplastic, biodegradable or compostable, which have become much more appealing, especially against the surge in concern about plastic pollution. 

Are bioplastics better for the environment?

One of the main problems with bioplastics is that they are not all designed to be disposed of in the same way or broken down under the same conditions. This makes it very confusing for consumers and results in items entering the wrong disposal systems – which means that they aren’t disposed of properly and risks contaminating the materials which are meant to be there. 

For example, you might think a compostable cup is a better choice over a plastic one because it can break down into carbon dioxide, water and biomass. However, many compostable cups only break down under industrial conditions which most people don’t have access to at home. Putting it in the recycling bin won’t help either and it will end up contaminating the recyclable plastic in the bin. So most of these cups will just end up in the landfill where they cannot break down because the conditions needed for that to happen will not be met.

Where does plant-based plastic come from?

A vast amount of crops, land and water is needed to make bio-based plastics. In order to make one tonne of the PLA (polylactic acid) needed to make bio-based carrier bags, you would need 2.39 tonnes of maize, 0.37 hectares of land, and 2.9 million litres of water.

As the demand for bioplastics grows, only 5% of the global production is expected to take place in Europe, with a staggering 81% due to take place in Asia, where countries face increased loss of natural habitats, pollution, and conflicts of land.

The new plant bottle project states that to begin with it will make 5,000 tonnes of plastic a year using sugars from corn, wheat or beetroot. And as demand for alternatives grows, it will look to use plant sugars from sustainably sourced biomass so that the rise in plant plastic does not affect the food chain. 

But Coca Cola produces about 108 billion bottles a year, so you are going to need an enormous volume of biomass (and land) to even meet a fraction of the demand, and that’s just one company. 

Are bioplastics the answer to our plastic problem?

The short answer is no. Globally around 300 million tonnes of plastic is made from fossil fuels every year – also making the industry a major contributor to climate change. 

Over the next few years, plastic production is expected to significantly increase which means there is going to be even more demand on the production of alternatives to meet the need to move away from fossil fuels. 

Bioplastics certainly have a role to play in a circular economy, but until we fully understand the life-cycle impact of them from production through to the end of life and supply the correct conditions for them to break down, we cannot use them as a plaster to fix our global plastic problem.

Further reading on bioplastics

Plastic Atlas 2019 – facts and figures on the world of synthetic polymers