哪個更可持續:鋁罐,塑料瓶或玻璃瓶?


56

當我看大圖(完整的生命週期分析)時,我想知道哪種飲料容器是最可持續的。

到目前為止,我可以看到以下幾點:

  • 運輸:塑料和鋁比玻璃輕,可以在回收的過程中被壓碎,這意味著與運輸相關的能源使用較少。
  • 原材料:我認為玻璃在資源可用性和循環利用次數方面可能是最可持續的-是嗎?
  • 污染:同樣,玻璃將是不破壞環境的最佳選擇。
  • 每種產品的回收能源如何?

我認為應該根據所含液體的體積進行評估。

39

I found a comparison here. My take on reading that is the following:

  • Aluminum is the most efficient in terms of energy saved in making a new can taking only 5% that compared to working from scratch.
  • Glass comes in second saving 20-30% of the energy in making new glass.
  • Plastic is a distant third since you keep degenerating to a lower quality plastic formula. (e.g. PET (type 1) soda bottles becomes carpeting and jackets)

Now I'm not sure if glass beats aluminum in a total energy consumed to make say a 12 ounce container in that perhaps the amount of energy required for glass is so much less than aluminum that using 70% of the glass number still beats 5% of the aluminum number. However, with no facts to back this up, my intuition tells me aluminum would still win in a side by side comparison.


13

Interestingly glass and aluminum have the same specific heat or close to it (about 0.2 J/g) but the mass of he container is much different, and aluminum has a much lower melting point (about half that F of Glass).

Estimating weight of a 12 oz beer bottle at 140 grams (that's prob. low), and going by internet searches to find that empty soda cans weigh about 14 grams, we get a sense that the amount of energy required to bring to melting point is about 5% that of the aluminum can than the glass bottle.

140 * 2700 * 0.2 = approx 75600 J to melt the glass bottle discarding enthalpy of fusion (which iirc doesn't affect glass).

14 * 1100 * 0.2 = approx 3080 J to reach melting point plus 398 * 14 = 5572 J to melt, approx 9kJ to melt the soda can vs 76kJ to melt the glass bottle.

As are all answers this is necessarily incomplete. It isn't clear to me what else goes into recycling either and whether there are other embedded complexity costs, but that's a base line.


24

Before plastic bottles became popular, recycle meant something different than today. It used to mean 'reuse' not 'remanufacture'. I would think reuse of glass bottles would be the most sustainable. Although I'm not aware of any soda manufacturers that reuse bottles in the US, there are dairies that reuse milk bottles now that glass milk bottles are making a comeback at local dairies.


0

When I lived in IL I was told that any broken glass went into the landfill. How much glass do you think is not broken when it is dumped into the recycling garbage truck? I think it is a terrible waste of energy to not recycle glass. Here is a good site for information: http://www.greenlivingtips.com/articles/182/1/Recycling-energy-savings.html Glass, plastic, and aluminum are discussed


3

What's best is if you pipe the water into your house, making for huge savings in transport costs.

Now, while this doesn't really apply to fancy things like pop and beer, it's really, really better to not drink bottled water at all. Systemically speaking, the rate that bottles and cans are actually recycled is dismal at around 15%. So in the end the difference in recycling costs don't really matter that much anyway.