The 2nd Law of Thermodynamics – The Gaping Hole in the Middle of the Circular Economy

A great article by Paul Mobbs, an independent environmental consultant, investigator, author and lecturer, and maintains the Free Range Activism Website (FRAW).

Why the latest buzz-phrase in consumer sustainability is not only failing to tackle the core problem, but why it is doomed to fail

Listening to Radio 4 this morning I heard the two juxtaposed keywords that I’ve learned to dread over the last couple of the years; ‘circular economy’. It’s a great idea, and I can’t fault the true belief of those promoting it. My problem is that the way they describe it has little to do with the physical realities of the world, and hence it’s really just a “get out of hell free” card for affluent consumers – who are, it would appear, the most vociferous proponents of this idea.

As is so often the case with feel-good eco-stories, the Today programme’s[1] interviewer was all light and fluffy; and obviously flummoxed because they did not have the confidence to ask any basic, challenging questions of the interviewee.

The segment was examining the new research[2] from Portsmouth University. They’ve found a ‘mutant’ enzyme from bacteria they found living on plastic in recycling centres. As with all enzymes[3] – like the things they add to washing powder so you can clean clothes without boiling them – these complex molecules accelerate chemical reactions by working on the chemical bonds which hold things together. In this case, the enzyme breaks down the bonds of the polyethylene terephthalate[4] (PET) molecule.

Great idea; and if shown to be ecologically safe, great chemistry. That’s not the issue here.

Enter ‘the Circular Economy’

The scientist then described the value of this enzyme as part of the ‘circular economy’[5] – a concept proposed in the 1980s, and popularized in recent years by organizations such a the Ellen MacArthur Foundation[6], of moving from a linear to a circular economic process:

‘Linear’ economy – meaning that materials are created, used and disposed as waste, requiring that new resources must be reduced to replace them, which is how the core of the global economy works today;

‘Circular’ economy – meaning that all materials and products are manufactured and sold so that their content can be fully recycled and used in new products once more, obviating the need to produce new resources to replace them.

It is a lovely idea. One which I would whole-heartedly support, but for one slight technical hitch I perceive in this concept; The Laws of Thermodynamics[7] – and my particular favourite, The Second Law of Thermodynamics[8].

The Laws of Thermodynamics arose in parallel with industrialization, having first been used to described the operation of steam engines. Over time science has perfected the principles of these ‘laws’ and now finds that they are universal.

The Second Law deals with irreversible reactions – that is, operations which once undertaken cannot be undone.

What the ‘circular economy’ idea would propose in relation to PET plastic bottles is: Take some natural gas (yes, contrary to the idea that plastics come form oil, most plastics are made from the light by-products of oil refining, but mostly natural gas and gas condensate) and turn it into PET plastic; then make a plastic bottle with a blow-moulding machine; use the bottle; then recycle the bottle, and keep recycling after each use – obviating the need to use more natural gas to create plastic. As a result, the use of the bottle becomes ‘circular’.

Sounds great, doesn’t it?

The thermodynamic restrictions of human hope

Of course, there’s always a big hairy “but” in situations like this.

In this case, the use of plastic represents a ‘reversible’ reaction – you can make plastic, and then recycle the plastic to make more plastic. Sorted!

The energy expended in doing that, however, is an irreversible[9] process. It can’t be recovered.

The Second Law dictates that energy can be used, but in the process the ‘quality’ (for which read ‘usefulness’, or ‘density’, or ‘value’) of that energy is degraded; and once degraded, that ‘quality’ cannot be recovered without using even more energy than was expended when the energy was first used.

For example, water flowing downhill can turn a turbine to make electricity; but it takes more electricity than that was generated to pump that same volume of water back to the top of the hill again.

Now at this point proponents of the circular economy will talk about using renewable energy, thereby avoiding the issue of finite resources being used to power the process. That’s true, up to a point; and that point is, what are those renewable energy system made from? Finite resources.

Limits to renewable energy

Just because renewable energy is ‘renewable’, it doesn’t mean the machines we require to harvest that energy are freed from the finite limits of the Earth’s resources[10].

There are grand schemes to power the world using renewable energy. The difficulty is that no one has bothered to check to see if the resources are available to produce that energy. Recent research suggests that the resources required to produce that level of capacity cannot currently be supplied[11].

The crunch point is that while there might be enough indium, gallium, neodymium and other rare metals to manufacture wind turbines or PV panels for the worlds half-a-billion or so affluent consumers (i.e., the people most likely to be reading this), there is not enough to give everyone on the planet that same level of energy consumption – we’d run out long before then.

For example, the first metal humans smelted[12] about 9,000 years ago was copper. Ever since copper has been a brilliant indicator of human development, with consumption increasing in line with human development ever since. One reason for that is that as industrial use has fallen (e.g., replacing copper pipes with plastic) we’ve used more copper for new technologies (e.g., electronics – roughly 14%[13] of the weight of a mobile phone is copper).

Copper also has one of the best, most mature recycling systems, but even then it’s been estimated that only half of all copper is reused[14].

The problem is, due to its long and intensive global use, we’re approaching ‘peak copper’[15] – the point where the remaining amount of copper in the ground, and more importantly its falling ore quality, reduces the amount which can be economically produced annually. And more significantly, the ecological impact[16] of the falling copper ore quality is that the energy consumed and the greenhouse gases emitted by production increase exponentially.

Now of course we’ll use copper more efficiently. And if we run short, rising prices will increase recycling rates – though it will also increase the disruptive theft[17] of copper in society. The difficulty is that, just last week[18], the copper industry announced that it worried about production after 2020.

Strategy is important, but ‘real’ change is critical

OK, back to the ‘circular economy’.

What really matters here is not so much the material used in production, but the energy density of production. Energy density isn’t just a matter of how much energy it takes to produce an article, but how long that article lasts. That in turn affects the ‘return’ on the energy invested in its production – or EROEI[19].

Let’s say a plastic bottle takes six weeks to be manufactured, filled, bought, consumed, collected and reprocessed to the point of re-manufacture. That’s good because recycling plastic can represent a saving of more than 50%[20] on the energy used to produce it compared to virgin materials.

What determines the long-term sustainability of this though is not just the one-time saving, but the viable fraction that can be reclaimed and reused.

Let’s assume that, at best, we can recover 60% of the content of the bottle over each 6 week cycle. After 1 cycle, 6 weeks, we have 60% of the material left. After 2 cycles, 12 weeks, we have 60% × 60% = 36% left. After three cycles there’s 60% × 36% = 22%. After four cycles, 13%, etc.

By the end of one year (8 or 9 cycles) we’d only have 1% of our plastic left.

The obvious response is, “well, let’s recycle more”. The problem is that achieving a higher recovery rate actually requires expending more energy, reducing the energy saved – and as you get nearer to 100% the amount required is likely to exceed the energy involved in producing new plastic from raw materials.

For example, recycling in densely populated urban areas is easy, because waste management is an essential part of being able to run an urban area. But what about more sparsely populated rural areas and villages? At what point does the energy expended running a collection vehicle exceed the energy saved from materials recovery? (answer – it’s completely dependent upon local circumstance, and so has to be evaluated as part of the planning process rather than generalized in advance).

“It’s consumption, stupid!”

It’s the same as the falling copper ore problem. The more diffuse your source, the more energy you have to expend to recover it. Getting the easy to find plastic, let’s say the first half, will be easy. Getting the next 20% might take as much effort. The 10% after that twice again. And the last 20%? It might produce no saving at all.

Alternatively we could extend the life of the bottle – by refilling instead of recycling. That would have a significant effect, but even then, on each refill cycle a certain number of bottles would be rejected.

Don’t ignore this option though. It is arguable that, in lieu of increasing recycling rates, extending the service life of resources probably has the best energy profile – since it reduces not only the need to re-manufacture resources, but also the need to recycle/replace them. The problem is that reuse often requires far greater change and co-operation by consumers – precisely the thing our ‘liberal’ economy hates doing because it involves dictating the actions of consumers.

Forget Bill Clinton’s line about ‘the economy’; “It’s consumption, stupid!”

More importantly, throughout this whole process, energy is expended[21]; and energy is the one thing we can’t recover. Therefore we have to avoid re-manufacture or recovery in the first place. The difficulty is that no one wants to advocate this – combining multiple reuse, high recycling AND longer service life – as it means the effective elimination of consumerism, fashion, ‘innovation’, and many of the other totemic traits[22] of the modern consumer materialist economy.

Then again, given that a large amount of the world’s wealth is derived from resource exploitation, any change to that pattern is likely to have huge implications for the day-to-day economy[23] that the most affluent consumers rely upon in order to consume.

The ‘Circular Economy’ must accept thermodynamic reality

Arthur Eddington[24] was a British scientist (and Quaker) who advanced physics and astrophysics in the first decades of the 20th Century, and popularized the theories of Albert Einstein – against the then anti-German and anti-Jewish prejudice of the science establishment.

In relation to the Second Law of Thermodynamics, Eddington produced a famous statement:

If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations – then so much the worse for Maxwell’s equations. If it is found to be contradicted by observation – well these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.

The ‘circular economy’ is, in my opinion, a ruse to make affluent consumers feel that they can keep consuming without the need to change their habits. Nothing could be further[25] from the truth, and the central reason for that is the necessity for energy to power economic activity[26].

While the ‘circular economy’ concept admittedly has the right ideas, it detracts from the most important aspects of our ecological crisis today[27] – it is consumption that is the issue, not the simply the use of resources. Though the principle could be made to work for a relatively small proportion[28] of the human population, it could never be a mainstream solution for the whole world because of its reliance on renewable energy technologies to make it function – and the over-riding resource limitations on harvesting renewable energy.

In order to reconcile the circular economy with the Second Law we have to apply not only changes to the way we use materials, but how we consume them. Moreover, that implies such a large reduction in resource use[29] by the most affluent, developed consumers, that in no way does the image of the circular economy, portrayed by its proponents, match up to the reality[30] of making it work for the majority of the world’s population.

In the absence of a proposal that meets both the global energy and resource limitations[30] on the human system, including the limits on renewable energy production, the current portrayal of the ‘circular economy’ is not a viable option. Practically then, it is nothing more than a salve for the conscience of affluent consumers who, deep down, are conscious enough to realize that their life of luxury will soon be over as the related ecological and economic crises[31] bite further up the income scale.

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