How we audit supplier emissions, and why it took three years
Getting usable scope 3 data from 2,100 suppliers was harder than any control system we have built.
Halden Systems Newsroom - - 1 min read
Halden reports scope 1, 2 and 3 emissions in its annual report. Scope 3, the emissions in our supply chain, took three years to get to a number we would put our name to. This is how, written up because every industrial customer we have is going through the same exercise.
Year one: asking
We asked our 2,100 suppliers for emissions data. About a fifth replied, and of those, fewer than half used a method we could compare. The exercise produced a spreadsheet and no usable number.
Year two: standardising
We settled on one method, published a short guide for suppliers, and paid for the largest 200 suppliers to be assessed by a third party. That covered around 70 percent of spend and produced the first number we trusted for that 70 percent.
Year three: estimating honestly
For the long tail we use spend-based estimates and say so. The report marks every number as measured, supplier-reported or estimated, and the proportion of each is on the first page of the sustainability section.
The principle
The honest version is more useful than the clean one. A single total with no indication of how it was built invites nobody to improve it. A total that says "70 percent measured, 30 percent estimated" tells you exactly where to work next year. Our target is 90 percent measured coverage by 2028.
The same principle shapes the reporting in our energy management practice. Full figures are on the sustainability page and in the annual report.
