Three scopes
Scope 1 covers sources the organisation controls: boilers, generators, company vehicles, refrigerant leaks. Scope 2 is purchased electricity, heat and steam. Scope 3 is the largest and hardest: purchased goods and services, business travel, employee commuting, waste, and the use and end of life of the product.
Data and factors
The calculation itself is a multiplication: activity data × conversion factor. Errors appear in two places. The first is incomplete data — one site's invoices are forgotten and the result can no longer be compared year on year. The second is factor confusion: different publishers' factors belong to different years and different countries, so the report must state which factor set was used.
Optifora collects activity data from measurement and invoice records, keeps the factor set on record, and compares years within the same set.