Appendix

Appendix 1 : Ecoinvent processes

Table A1 List of ecoinvent 3.10 processes used in the GHG reduction quantification model

*removed the power adapter production and waste treatment, and the device waste treatment

**removed the device waste treatment

Appendix 2: Emission factors of Apple devices

Table A2 Mass and GHG emissions from production for iPhones gathered from Apple Product Environmental Reports, for a selection of recent models.

Table A3 Mass and GHG emissions from production for iPads gathered from Apple Product Environmental Reports, for a selection of recent models

*2021 is also considered in the average iPad emissions to have a bigger sample

Table A4 Mass and GHG emissions from production for MacBooks gathered from Apple Product Environmental Reports, for a selection of recent models

Table A5 Mass and GHG emissions from production for iMacs gathered from Apple Product Environmental Reports, for a selection of recent models

Appendix 3: Refurbishing Impact Ratio

Table A6 The Refurbishing Impact Ratio is calculated by dividing the Results refurbished device column by the Results new device column. This fraction is then applied to the emission factors for new device impacts used in this study to obtain the emissions from the refurbishing process (Table 3).

where,

Table A7 The amount of full refurbishment activity input to each device type to obtain the desired emission factor for refurbished devices, as presented in Table 3. Calculated by dividing the desired emission factor for refurbished devices by the emission factor for one full refurbishment activity. The full refurbishment activity is described in Appendix 1.

Appendix 4: WEEE statistics

Table A8 The national WEEE waste treatment rates are summarized. Sources are indicated in the column names. Percent of all small IT e-waste that is recycled/reused (column 3) was calculated by multiplying the Percent small IT e-waste separately collected (column 1) by Percent of separately collected small IT e-waste that is recycled/reused (column 2). Percent of all small IT e-waste in municipal waste stream (column 4) was calculated by subtracting Percent of all small IT e-waste that is recycled/reused (column 3) from 100%. Note that when percentages were >100, they were automatically set to 100.

Appendix 5: Ecoinvent activity smartphone changes

• Smartphones are the most frequently refurbished device type, so avoided emission calculations are particularly sensitive to their emission factor

A comparison of detailed life cycle inventories was the preferred approach, but was not possible due to a lack of transparent data on smartphone composition. Notably, the amounts of the most impactful smartphone components (mainboard, printed wiring boards, and integrated circuits) could not be found to adjust inputs to the ecoinvent process.

For Apple iPhones (devices with most sales globally), the identified values are presented in Table A2, with an average of 64±15 kg CO2eq/device. Emission factors for other smartphones are summarized in the table below, and show an average emission factor of 49±13 kg CO2eq/device. These values shall be used for the emission factors for iPhones and other smartphones, respectively.

These values are around 25-50% greater than the smartphone production emission factor from ecoinvent 3.10.

To implement this change in the model, the amount of key inputs (mainboard, printed wiring boards, and integrated circuits) in the ecoinvent smartphone process was increased to reach the desired final emission factor.

Additionally, exchanges for the charger production, smartphone waste treatment, and cable waste treatment were removed from the process, to align with the project system boundaries.

Table A9 The non-Apple GHG emissions from manufacturing of smartphones gathered from manufacturer environmental reports, for a selection of recent and popular smartphone models. EF stands for emission factor.

Appendix 6: Market share of new and used devices

The market share of new and used devices sold annually in Europe was used to determine the repartition of avoided new and refurbished devices in the baseline scenario. Most data were available for smartphones, taken from survey responses from 2022, and are presented in Table A10. The average values used for the GHG reduction quantification are a market share of 13% for refurbished smartphones, and 87% for new smartphones, as shown in Table 5.

Table A10 Breakdown of refurbished and new smartphones sold in European countries in 2022.

Similar detailed data were not available for other device types. Survey responses on the interest in buying a given refurbished device type were used to adjust the smartphone data in Table A10 proportionally to other device types (Table A11). The results from PCs were applied to laptops, and the results for TVs were used as a proxy for screens.

Table A11 Survey results asking respondents if they would be interested in buying the device type refurbished are summarized. The ratio of the results for smartphones compared to other device types was used to proportionally adjust the average percentage of refurbished smartphones gathered in Table A10.

Appendix 7: Residual value calculations

Table A12 Sample prices for a new Apple iPhone.

Table A13 Sample prices for a new Samsung smartphone.

Table A14 Sample prices for a new Apple iPad.

Table A15 Sample prices for a new Samsung tablet.