Exeter City Council – 24th January 2020


Bioplastic packaging is often seen as a ‘green alternative’ to single-use plastic, but is this really the case?

Cornstarch bags, for instance, are promoted by some as the answer to single-use plastic bags. Alas, they’re not.

The truth is there is no truly viable end-of-life solution for them at the moment beyond incineration at Energy Recovery facilities. In any case, nothing designed for single-use can solve the issues posed by anything else designed for single-use.

Think of what a cornstarch bag is made from: sugar derived from corn, usually genetically modified as it is generally the same crop used to produce feed for livestock.

Yes, corn is a natural product and not a finite resource (as long as we are able to grow crops – see GM), but it’s a monoculture, taking up land, reducing biodiversity, using vast amounts of energy and water to grow, harvest, process into bags.

And the other selling-point of bioplastic – its ability to decompose – isn’t as straightforward as it is advertised to be. Bioplastic doesn’t usually rot under normal household composting circumstances, because the compost heap won’t get hot enough, and how many of them would actually find their way onto a compost heap anyway? How many people have a compost heap? How many of these bags will just be thrown away?

Using them to line kitchen caddies in areas that have food waste collections isn’t appropriate, either. Food waste processing plants don’t want them – they don’t break down in the anaerobic digestion process and are too stretchy to remove easily, unlike normal plastic bags.

According to letsrecycle.com, “WRAP [Waste and Resources Action Programme] said unless bioplastics are rapidly soluble or dispersible, a form of pre-treatment such as shredding is required to make them suitable for processing by wet anaerobic digestion.”

In other words, they are too sturdy to be composted effectively even in industrial food waste processing facilities unless they are put through further energy-consuming processes first, which isn’t going to happen for all sorts of reasons of impracticality.

To make bioplastic durable enough to be useful, it can’t be made easily soluble or dispersible. Can you imagine a coffee-cup made of readily-soluble material? Or a shopping bag that splits the moment you put a baked bean can in it? Hardly practical.

So, food waste plants extract all bags from the waste and send them to the incinerator. Bioplastic bags are NOT composted with the food. You may as well use a plastic bag; in fact the plant would prefer it if you did, because it takes less energy, fuel and time to remove the plastic and results in less contamination of the soil-improver, making it more suitable for local farms. Plus the plastic bag will probably have had a smaller carbon footprint to begin with.

Authorities that collect food are now faced with a difficult proposition: promoting the use of plastic bags to line food waste caddies. It goes against the grain of public feeling somewhat, but things are never as simple as they appear.

A thin plastic bag is made using by-products of the oil-refining process or of natural gas production. While the impact of fossil fuel production on the environment has long been known, plastic uses under 10% of oil and gas extracted in Europe, with more than 80% being used for electricity, heating and transport. Both bioplastic and standard plastic materials will go through energy- and fuel-intensive processes.

By avoiding plastic, we are not avoiding the consumption of fossil-fuels.

So which is best? Neither is really that great, but if I had to make a choice, I’d choose plastic. I’d use an empty packet that had my frozen chips in it.

I haven’t mentioned paper yet. Not because I was waiting to reveal it as the true green alternative – far from it. It’s often touted as the solution to all our plastic woes, but it just isn’t.

I’m sorry to say this is just another example of making a problem worse by trying to make it better…or trying to look like you’re trying to make it better.

Paper production and transportation is incredibly fuel- and energy- and water-intensive – much more so than thin plastic. It tends to result in the deforestation of old wood that is often replaced by a non-native monoculture, severely inhibiting the biodiversity essential for life on earth.

Planting trees is a really good thing; but cutting down forests is a different matter. We need more trees, not more new ones and fewer old ones.

Why do they use old wood? Because it has nice long fibres.

Think about all the fuel used in cutting down trees and hauling them. All the water and energy and chemicals used in pulping, squashing, bleaching, drying, cutting, transporting.

The embedded carbon and environmental damage in a paper bag is significant.

So paper is not a solution to plastic. It may rot quicker in nature, but the harm it does before it gets there can be considerably higher than that caused by plastic.

As ever, reducing unnecessary packaging and reusing what bags we already have is key. Plastic itself isn’t the problem; the disposable culture is the problem.

There is no one-size-fits-all solution. We must all just reuse what we have as much as we can, reduce waste where we can and ensure we’ve thought carefully about every purchase we make.