We helped New Zealand Post find the most environmentally friendly alternative to replace their A5 courier bags made of virgin LDPE. Our Life Cycle Assessment (LCA) in 2020 compared their original bags to a range of packaging options that were equivalent in function and size.
NZ made recycled LDPE bags have the lowest carbon footprint
Our study found locally manufactured LDPE bags that contain 80 percent recycled content have the lowest carbon footprint of all options we considered.
We compared five alternatives to the original bag
New Zealand Post recognised that customers may not choose the flat, Kraft paper bag as it feels more like a traditional postal envelope than the original plastic courier bag. Therefore, we included a padded Kraft paper bag in the study as a closer comparison. As the only padded bag option, it is functionally superior to all other bags we assessed.
Reusable bags weren’t included in our study
The purpose of our study was to identify the best-performing single-use courier bag available. Developments need to be made before reusable bags are feasible for widespread use.
We looked at the entire life cycle of each bag
Our study has a ‘cradle-to-grave’ scope, covering the impact of the bags over their entire life cycle. We investigated three different disposal options: landfill, recycling, and composting. This study follows international standards ISO 14044 and ISO 14067 and has been critically reviewed by three independent experts.
NZ made recycled LDPE bags have the best environmental performance overall
The carbon footprint of the NZ made recycled LDPE bags is less than half of NZ Post’s original bag made of virgin LDPE. In addition to the carbon footprint (the primary indicator), we assessed all bags using other indicators — such as water consumption and waste production — to make sure that we were taking all environmental impacts into account. The recycled LDPE bags made in New Zealand performed best in 11 of 14 indicators.
The carbon footprint of each bag was measured by its Global Warming Potential, or GWP over 100 years.
A step in the right direction
New Zealand Post can reduce a significant amount of their carbon emissions by replacing their original courier bags with the recycled LDPE bags made in New Zealand.
Get the main findings of the LCA in our case study "LCA of NZ Post: In a nutshell" below .