[olejorgenb]

"too heavy" is of course relative, but the addition cost/energy-use of the heavier transportation surely is non-trivial? If the bottles are to be reused, volume become an challenge.

I admit I don't have any references at hand, but I'm quite sure I've seen articles claiming plastic bottles "win" by a comfortable margin from an energy perspective.

Of course - energy is not everything.

[strogonoff]

I’ve seen analyses showing that aluminium actually is less energy-expensive than even plastic when it comes to transportation[0]. Initial aluminium is pricey, but recycled is cheap and unlike plastic it’s infinitely recyclable. But then yes, there is the inner layer of plastic in today’s aluminium cans, and proper glass beats both in terms of cleanness when it comes to the food it contains.

Additionally, the energy needed to produce even the initial, energy-intensive glass or aluminium could perhaps come from renewables and perhaps some emissions can be captured given enough motivation. (And when it comes to transportation perhaps today’s approach of lugging finished bottles around the globe can evolve towards moving source material and packaging it locally.)

The math is not straightforward.

[0] https://www.reuters.com/article/world/plastic-bottles-vs-alu...