Saturday, August 25, 2018

Weird's a hobby`

Or at least distraction:

9 20oz bottles per pound PET = 380 fl. oz. / # container material
Can't quickly find on google the figure for PET, but HDPE (milk bottles) is 18,690BTUs/#, and it is reasonable to assume PET is similar. You can recycle it a fixed number of cycles, but eventually it will end up in a landfill or incinerator.

31 12oz cans per pound of Aluminum = 374 fl. oz. / # container material
Takes 6,000BTUs/# to recycle aluminum (from the link below you'll need to do some math based on there statement that it saves 237MM BTUs/Ton and it uses only 95% of the energy of refining new).

Aluminum might end up in a landfill, but it otherwise is effectively infinitely recyclable unlike PET with current technology.

So...I actually surprised myself doing the math. There is about three times more thermal energy stored in plastic bottles than it takes to recycle an equivalent storage capacity of aluminum bottles. You'll spend some of that of course in transportation back to a refinery, but it is a big cushion to work with. A big enough cushion I suspect it even offsets fossil fuel used to mine and transport the raw ingredients to make aluminum.

In this case it is also not necessarily an either/or, since aluminum smelters use electricity, and at least for raw production in North America, that is usually hydroelectric (thus the bulk of energy used to refine virgin aluminum.).

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