On why we should stop worrying about disposable coffee cups

The university I work at has bought into the idea that their catering outlets should have reusable coffee cups rather than disposable ones. I am mystified as to how exactly this faux environmental concern came about, so I thought some maths might be a good idea.

reusablecup

The embodied energy content of a disposable cup is 0.153 kWh. Using 2017 data for carbon emissions, this creates 0.0083 kg of CO2 emissions. Again, using 2017 data, the average UK car is responsible for 0.294 kg CO2 emissions/mile. In other words, you would need to not use 36 disposable coffee cups in order to generate the same amount of CO2 emissions as you would from driving 1 mile in your car. Note, this is completely ignoring any impacts from what you might choose to drink your coffee out of instead and this should also be factored in. But hopefully by this point you’d have decided that your transport choices are more important than your coffee drinking choices.

But assuming you definitely did want the coffee and were going to buy a reusable cup… Obviously, these require more energy to manufacture than a disposable paper one. I’ve not weighed one of the reusable cups at work, but using data from here, you would need to reuse your cup 12 times before the energy cost of producing it was lower than using disposable paper cups (it’s probably a few more times than this in practice, because I haven’t accounted for the impact of washing your reusable cup). 12 reuses probably isn’t too difficult to achieve for most people, so you might find this number quite encouraging and feel good about ‘doing your bit’. I’ve hesitated before doing this calculation; my fear is that readers will ignore the fact that the actual numbers are very small; your coffee drinking is not an important part of your environmental impact. And herein is the tragedy; many people who would like to do the right thing are being sold the idea that small changes make big differences. This simply isn’t true.

So what should we be doing instead? This is a great opportunity for me to quote one of my all time environmental heroes, the late Sir David Mackay.

“What should I do: Put on a woolly jumper and turn down your heating’s thermostat to 15-17C [20 kWh/d]; stop flying [35 kWh/d]; drive less or more slowly, cycle, walk, use trains [20 kWh/d]; keep using old gadgets [4 kWh/d]; don’t buy clutter [20 kWh/d]; eat veggie six days out of seven [10 kWh/d]”

David Mackay, SEWTHA, p219.

David Mackay was the author of Sustainable Energy without the hot air. If you’ve not come across this book, it is well worth a read and is freely available online. If you believe that ‘every little helps’, I suggest you start with chapter 19. Sadly David died very young, fairly shortly after he’d relinquished his professorship at Cambridge in favour of working at the Department for Energy and Climate Change as their chief scientific advisor. This was an incredibly bold move from a man who knew how to make a difference. His blog is poignant – his last posts were reflecting on life, death and cancer, but if that’s too sad, do read the preceding 5 years worth of posts.

As a slight aside. Whilst I was thinking about all of this today, I came across a report to the House of Commons Environmental Audit Committee on disposable coffee cups. It’s worth a read, because it’s starting point is the proliferation of coffee shops and how we are all drinking far more coffee on the go than we used to, and it then moves seamlessly into detailed discussions about why coffee cups aren’t being recycled and what should be done about it. Any mention of not consuming in the first place? No, of course not, because economic growth is fuelled by consumption, and economic growth is what we are wedded to. If anybody has any bright ideas about what to do about this, please stand for election, you have my vote.

9 thoughts on “On why we should stop worrying about disposable coffee cups”

  1. The reason disposable coffee cups are all over the news right now is nothing to do with embodied energy content, rather it is concern over plastic waste ending up in the oceans etc. So whilst it is certainly interesting to consider how much energy could be saved (or not as the case may be) by switching to reusable it doesn’t really address the issue at hand.

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    1. Yes, agree this is the reason. Unfortunately, coffee cups are nothing to do with marine plastic waste (over 50% of the plastic in the ocean comes from just 5 countries, and the UK is NOT one of them!). I’ve written something on this, and given that it’s fairly topical I’ve touted it to some of the national press. It will appear on this blog fairly shortly if I don’t get any interest from them.

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      1. Recently I found myself watching a video of the 2011 Tohoku tsunami and being struck by the vast amount of trash swept out to sea when the waters receded. Before that was the 2004 Indian ocean tsunami and I am wondering whether between them they account for much of the recent increase in plastic washed ashore or accumulating in gyres.

        Regarding your statement that the UK is not one of the top 5 culprits I did a search and came across a claim that China alone is responsible for a quarter of ocean plastic waste. But at least until recently the UK has been shipping huge quantities of plastic waste to China. How much of that ends up in the ocean and to which country is it attributed?

        By the way, I saw your post when a friend on Facebook shared it. I would normally comment on Facebook but this time for some reason I thought no, I will comment on the original blog entry so that the author gets to see it and respond. I will try to remember to do that more in future.

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  2. Thanks for your comments, and for posting here rather on facebook, it does make it easier for interested people to find the discussion in the future.

    You’re absolutely right; in the UK we have been outsourcing our pollution to China, and it’s great that the Chinese are choosing to crack down on this. We tend to think that waste management infrastructure is the norm, but unfortunately in many countries it isn’t. What I think would help is a requirement that prevents us from exporting wastes to countries without suitable infrastructure. Once waste has been treated to a certain standard it is regarded as a ‘product’, and exporting this to other countries is much less problematic.

    Another sobering thing to think about in relation to marine plastics is that our attention is drawn to it because it’s bouyant. Material that sinks, we know almost nothing about, and the vast majority of waste materials would tend to sink.

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  3. Futher to waste plastic ending up in the ocean, China not taking our waste plastic anymore and our restrictions on landfill, why don’t we look at how Sweden is dealing with this (actually importing waste to make energy) and bring in this infrastructure?

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    1. Interesting point. We already have a number of waste to energy plants in the UK, but are much less reliant on it than Sweden. It’s often not a particularly popular technology with local communities (waste incineration has a historically poor reputation). Whether or not waste to energy is environmentally preferable to landfilling depends on your viewpoint. You might argue that landfilling something as inert as plastic is carbon sequestration and therefore a good thing. Or you might say that it’s better to displace another fossil fuel for generating electricity by burning waste instead.

      Waste to energy plants (like all waste infrastructure) are extremely capital intensive, so you need a guaranteed source of feedstock in order to justify building it in the first place (e.g. you’d want waste supply contracts from councils for 10-20 years). Because of this, and the fact that plastic has a lot of energy in it, there is a real risk that building facilities to burn plastic will effectively prevent us from developing plastic recycling infrastructure.

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