Onlycans: Part 1

This is the beginning of our series on the uses and misuses of glass versus aluminium. We want to show what we have learned on the energy usage (and wastage) that goes on across the industry coming solely from the packaging side of things.

Onlycans: Part 1

Welcome to our Onlycans series. We’ve mentioned before that we intend on reducing our glass usage and doubling down on adopting the aluminium approach, and through these brief posts we hope to show you why.

Now you might be thinking to yourself “but guys, I thought using glass was good? As long as I recycle then I’m still doing alright yeah?”. The answer to that is both yes and no……but mostly no. This mini-series aims to pull back the curtain a little and explain how a lot of the numbers shown can be deceiving and what we believe the best practice should be.

This part aims to give you a brief introduction into what we mean about glass and aluminium usage when talking about recycling and making them from scratch (their raw materials).

Before I get into the energy savings and how better we could be spending this energy, we need to start with mass (or weight).Everyone knows glass and aluminium are completely different materials, glass is heavier and cracks more easily while aluminium is lighter and stronger but yet they’re both very commonly used as drinks containers. They’re both convenient and easy but what makes using aluminium surprisingly more energy efficient?

To answer this question let’s look at one single 200ml glass bottle. We’re using a 200ml glass bottle because that’s what we use in our case study (Onlycans part2). This will weigh about 150g depending on the manufacturer. However, one single 200ml can will weigh about 8g. You might be able to see already, but, the mass of glass needed to make one 200ml bottle is the same as the amount needed for NINETEEN 200ml aluminium cans. This means that one kilogram of glass can give you about 6.7 bottles. Whereas 1kg of aluminium can give you about 127cans. Are you starting to see why using cans are better? If not, let me try to make it clearer.

You see, numbers don’t lie, but it’s the interpretation of them that can lead to confusion. We’ve all seen it before “recycling your glass bottles saves 30% of the energy compared to making a new one”, anyone would see this and think “jeez that’s a pretty good saving.” And they’re right, it is a good saving. But what this doesn’t tell you is how much that quantity of energy actually is and what the real picture is like when you can compare it to…say, aluminium which can save about 95% of the energy when recycling.

You see the 95% and the 30% reduction in energy but you can’t compare them because you don’t know the starting points. So let’s try it. If you want to make 1kg of glass bottles from scratch, its going to cost you about 14,020kJ.

If you don’t know, a kJ (kilojoule) is a unit of energy in the same way that calories (you know, those things in our food that terrify us?) are another way of quantifying energy.  Anyway, you’ve got 14,020kJ (2,093kJ per bottle) from scratch or, if you were to use recycled glass bottles, it’ll cost you about 9,814kJ (1,465kJ per bottle).This is enough energy to power 1 laptop for 54 hours. I know these numbers might mean nothing to you just now but please bear with me and it’ll all make sense.

On the other hand if you want to make 1kg of cans from scratch it’s much more energy intensive overall at 54,000kJ but less so on a per can basis(425kJ per can). However, if you are to use recycled aluminium then the energy cost drops significantly down to 2,700kJ (21kJ per can), or about1 laptop for 15 hours.

I know all these numbers are probably boggling your mind right now, so let me sum it up quickly with the help of some sweet graphics by looking at the energy requirements on a per can and per bottle basis. Still using our laptop analogy to give us some perspective. Were each whole clock counts for 1 hour of charge.

Energy efficiency isn’t just about where your energy comes from, it’s also about how effectively it’s used. And we think the benefits of using cans outweighs that of using a cool looking glass bottle.

This is energy being spent on glass that could be saved and spent elsewhere. Now, looking at this example for a little 200ml bottle might make you think “that’s not that much though, it’s still quite good”. But what we’re missing is the bigger picture, this is just one bottle, a small one at that. What do you think this looks like when you have over 300million of them?

This is exactly what we’ve tried to answer in part 2 of our Onlycans series: The Real-Life Case Study.

If you’re still interested in finding out more, great, we’ll see you for part 2.