Existing Reap Users

Methodology and Data

SEI's methodology takes the national carbon dioxide accounts which are broken down by industrial sector and uses input-output analysis to disaggregate the data down to final demand. This produces ‘conversion factors' which enable the impact in tonnes of carbon dioxide to be calculated for each pound (sterling) spent on any consumption category.

In summary this means that if we know what money is spent on different products or services, using a series of input-output tables we can convert it to a measure of CO2. 

The input-output tables show the purchases made by each sector of the economy in order to produce their own ‘output', including purchases of imported commodities as well as the consumption of products and services by other sectors.

The conversion factors associated with each product reveal the full environmental impact along the complete supply chain of manufacture. For example, a unit spend on a travel hairdryer will sum the CO2 associated with the assembly and manufacturing of the product, the drilling of the oil to produce the plastic, the manufacturing of the machinery used to drill the oil, and so on.