How did you calculate the carbon emissions of a paper receipt?

In order to calculate cradle to grave emissions of an average paper receipt in the UK, the Carbon Trust made assumptions on type and size of paper receipts. The following assumptions were made: 

• Most common type of paper used in receipts was Thermal Paper 
• Thermal Paper Receipts average size and weight was calculated based on industry averages. 
• Receipts are on average 9 inches in length and 3.125 inches wide
• Three sizes were estimated based on an average grams per square meter of 50, 58 and 65 g/m2 

The paper receipt calculation included emission from the paper production process, material transport, printing emissions (average electricity consumption and assumption of heat-based printing therefore no ink) and finally the end of life treatment of receipts. The Carbon Trust looked at two different end of life scenarios including:

• UK average split of recycling, incineration with energy recovery and landfill
• 100% landfill scenario

For receipts that end up in landfill (which is almost all of them, as they can't safely be recycled) the cradle-to-grave emissions were found to be 2.5g CO2e.