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methodology.md

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Basic methodology

We focused on CO2e prevented. We calculate the CO2e prevented by repair using the following formula:

CO2e emissions prevented by repair (kg) = CO2e emissions prior to usage (kg) x (rate of "displacement" of a new purchase)

  1. We prioritised the "most relevant" device categories, based on those defined in the Open Repair Data Standard (ORDS), with the addition of a few unpowered product categories.
  2. We collaboratively sourced AS MUCH data as possible on pre-use CO2e footprint (i.e. in manufacture & distribution) for these priority categories
  3. Each piece of data has a source (link, year) or as a last resort, results from a proxy assumption (indicated)
  4. Finally, we rated data based on a data quality matrix: representativeness, age, reliability - see DQI tab for more

Assumptions

  • consumption of materials during repair insignificant
  • gains by upgrade to "energy efficient" device insignificant (especially as large appliances such as washing machines are out of the scope of this work)
  • variations in distribution impacts between Europe and North America insignificant (especially because distribution tends to represent a tiny proportion of the total footprint for all products covered)
  • average rate of displacement

Definitions

  • Displacement rate: the rate by which we prevent a new manufacture. Our biggest – and most necessary – assumption is that a fix at a repair event extends an existing device’s life, which will prevent carbon emissions from the manufacture of a new gadget. We assume each successful repair displaces a new manufacture by 50%. That is, that a repaired device will live on for 50% longer than its intended life.
  • CO2e: Carbon dioxide equivalent or CO2e means the number of metric tons of a greenhouse gas with the same global warming potential (GWP) as one metric ton of carbon dioxide (CO2) over 100 years. Click here for a more detailed explanation. It is the standard way of allowing comparison between emissions of different types of greenhouse gas (such as methane).
  • Life Cycle Assessment (LCA): a methodology to calculate a range of environmental impacts of a product at each stage of its life (typically: production/manufacture, distribution/transportation, use and end of life). This tends to include global warming potential (GWP) expressed as CO2e as well as other measures.

Limitations

LCA reporting is complex. LCA data for any given product can be calculated in a number of different ways depending on its purpose and tends not to be designed for comparison with other products. For these reasons, the data in this document should be understood as giving approximate CO2e values. Rather than provide exact measurements and calculations, the main aim of this data is to be an educational tool to demonstrate that the embodied impact of the products we buy (and repair) is significant.