30 May 2018 Dealing with Plastics.

I've tried to keep my cool, but finally I've snapped. I read yet another article about biological recycling of plastics and can't take any more.

The background to all this is my slow realisation that one group that consistently contribute to the trashing of the planet are greens. They are, in general, nice and well-meaning, but their actions have a strong tendency to waste, not preserve resources1. To put it in my favourite phrase: "The trouble with greens is that they don't realise that resources are limited".

Saving the planet is both necessary and hard to do. Any "green" resource that gets distracted from the key task is both a positive waste of real resources - and a negative reduction of resources from the key tasks because resources are limited.

A typical example is the response to the plastic garbage in the Pacific. Politicians are jumping to ban plastic straws. What are the consequences of such a ban? They are a distraction from the fact that the plastic in the Pacific is not from a few badly-disposed of plastic straws. It's from a systemic lack of large-scale waste disposal facilities in the key countries that are provably providing the majority of the plastic, including China, Thailand, the Phillipines and Vietnam. If we care about the Pacific (and we should) then most of our "anti-plastic" energies should go into providing a proper waste recycling system in those countries. This is a huge challenge, but compared to it, everything else is a frittering of resources.

Ah, but what about pollution on beaches in the West? Again, plastic straws in pizza parlours are irrelevant. There are two issues here. The first is an issue of handling litter properly - a difficult issue, but if we care about the environment then we can direct resources to tackle it. The second is that plenty of the shore-line waste is from the fishing and shipping industries, both of which are making major efforts to improve things. Plastic straws are a distraction from supporting these major efforts. Why haven't shipping lines cleaned up their act more quickly? One reason is that it needs $millions of investments in port-side facilities for handling the waste from ships. It's not glamorous, it's not "cost effective" (ultimately the consumers will pay for this), but it's both necessary and happening right now.

Oh, and what about replacing plastic straws with - well, with what? Getting rid of straws may or may not be a good idea. But replacing them with "paper" straws may throw up as many problems as it solves. First, the straw industry has to spend money and energy investing in new equipment. Second, a paper straw is unusable so it has to be a coated paper. It has to be coated sufficiently well that it won't fall apart in a drink. Which means that it's not going to disappear overnight if left as garbage. The energy cost of making the straws won't necessarily be lower. And how will this straw be disposed of? As a pure plastic straw it could, in principle, be nicely burned to yield energy. Most probably the paper straw will go into landfill where it will (effectively) last just as long as the plastic one. All that effort and disruption to solve a non-problem while distracting from a very real one. That's what greens do over and over again.

Bio-based solutions

Today (and this is what made me snap) I read that meal worms can be used to digest PE2. Hooray, we can dispose of PE in a natural way. But hold on. What do they convert the PE to - oh, CO2. How efficiently do they do it, how much extra energy would they need to keep the meal worms chomping away, what sized facility would they need, how would you dispose of the meal worm waste? I doubt that any of those questions have an answer that would make this a sensible way to convert plastics to CO2. So all this work is a waste of resource when we know that we already have a way to convert plastics to CO2 - and extract 20MW to provide electricity to local housing, as is done in my home town of Ipswich.

Ah, but burning rubbish is evil, nice meal worms inefficiently chomping it up is good. That's the sort of "green" thinking that drives me mad. Sure, 30 years ago, rubbish incinerators were dirty and polluting. But this is the 21st century and my local thermal recycling facility works closely with the local community, puts all its data on-line and is taking an otherwise difficult-to-handle waste and converting it to useful energy. Is this ideal compared to, say, 100% recycling of every plastic or 100% returning to the environment? No! Is it the best-available option for the next ~25 years? Yes.

But surely we can recycle PE, PP, PET, PS and the other "unnatural" polymers. In theory, yes, in practice it is not scaleable other than, perhaps, for PET but only then with a massive infrastructure which itself consumes resources and may be a distraction from really saving the planet. PET bottle recycling (via a deposit) may be net beneficial in the long term, but again think of the resources need to implement the structure, the energy costs of moving bottles back to be recycled, the space needed, the time, the distraction. As I'm not dumb enough to keep swigging water out of PET bottles, I don't have too many to throw away, but those I do put into my plastics bin travel a few miles and get swiftly converted into electricity.

Talking of PET, a few months ago there was another fuss about some bacteria that could eat PET. I took the trouble of reading the research article. My scientific advice? Don't hold your breath waiting for this to solve the PET issue. Again, it's another green distraction


In principle there are plenty of bioplastics. But in terms of scaleable quantities that can make a difference to the planet (and ignoring the starch-based ones that have interesting minority uses that don't scale), there's PLA3 (a bit like PET), PHB (literally grown by bugs and an attractive polymer for some special bio-applications), PHAs - a group with promise (e.g. PBS) but so far little delivery, and some non bio-based ones (e.g. from BASF) that are, like PLA, "compostable".

In the short term this means PLA and its blends. We use plastics because they are tough and strong, which means that they have to be pretty robust - they can't just dissolve in water or fall apart from the heat of a cup of tea. It turns out, therefore, that none of these bio-based polymers are simply "biodegradable" - if you throw them into the hedge row or on the beach, they will hang around more or less as long as PET. Instead they are "compostable". This is a term with an international standard meaning and it says that if you throw them into a professional, controlled composting system, they will fall apart in a reasonable time, yielding material that can end up, say, on a farmer's field without poisoning it.

Now here's the thing. After years of work to bring PLA (etc.) up to scale and excellent work to standardise them as compostable, municipal composting systems do not want to take PLA waste (they explicitly ban "biodegradable packaging"). There are two reasons cited for this (I've checked both in the UK and Germany). And they show how sloppy green thinking gives us the worst of all worlds.

  1. Consumers aren't sufficiently well-educated to reliably throw only 100% compostable plastics into their green waste. And sorting systems cannot handle leaves, twigs, tea bags while reliably distinguishing between, say, PLA (good) and PET (bad). A well-intentioned effort to accept these plastics would end up polluting an otherwise excellent method of disposing of (real) green waste.
  2. Although PLA (etc) pass all the official composting tests, in real-world municipal composting facilities they just don't seem to break down fast enough, completely enough, so the resulting compost is unusable on farms etc.

The worst of all worlds

So by encouraging $billions to be spent on bio-based plastics which gain some of the green-ness by being fully compostable back to nature, we have ended up with a situation where PLA (etc.) is either thrown into landfill or burned (sensibly) like any other plastic to gain at least some extra use at the end of life. And, of course, these bio-based plastics aren't necessarily all that good for us. You have to factor in the land they use to grow the raw material (even if it is so-called waste rather than sugar), the big chemical factories built to do the conversions, the energy required to convert biomaterial to plastic, the disposal costs of the liquid wastes from the fermentations. The arguments that this is a net benefit are now reasonable; but PLA is a tiny, tiny fraction of all polymers, it is ill-suited to many applications, there are no foreseeable alternatives that will scale to displace PE, PP, PET, PS, Nylon. So we have constructed a major distraction, using up resources, creating confusion about what "compostable" means.

Saving the planet

There are only a few, large-scale things that will help save the planet. Everything else is at best a distraction and at worst a positive waste of precious resources. Consuming less "stuff" is, of course, a key. In terms of plastics, in the relevant timescale of 25 years, I see no possibility of significant more recycling of the current plastics, no significant chance of them being replaced by demonstrably greener alternatives (either polymeric or paper or starch based). In the West, therefore, using the energy contained within the plastics as an alternative to coal-powered energy is a no brainer. In those countries that are filling the Pacific with plastics, thermal recycling would be the obvious, scale way to deal with serious quantities of high-density thermal energy whilst also reducing reliance on coal.

Greens will always find arguments against thermal recycling (there is, for example, still some ash to be disposed of in landfill). That's fine - it's always good to identify problems. But their problem is that they are great at finding fault and lousy at coming up with ways that will actually save the planet. If they can propose viable ways, at scale, to, say, recycle current plastics or replace them with bio-based ones, well, I'm happy to hear them. Till then, let's get on doing stuff that demonstrably is less bad than any current alternative. Let's do stuff that works rather than stuff that makes us feel good while making things positively worse.

1 I'm co-author of two academic book chapters, due out this year from a respectable publisher, which state my anti-naive-green case in suitably academic language.

2 Polymers: PE=Polyethylene; PP=Polypropylene; PET=Polyethyleneterephthalate; PS=Polystyrene

3 Poly(lactic acid). I wrote a chapter in the PLA book edited by Auras et al. so am fairly familiar with it. The others are: PHB=Polyhydroxybutyrate; PHAs=Polyhydroxyalkanoates, PBS=Poly(butylene succinate)