It is a cost of access to the market, not a conventional return on investment. The calculation rests on two things: (1) the difference in Ic Construction score against the collective sheet of your trade association (how many fewer gCO2e per functional unit), and (2) the number of public or private tenders where that difference lets you clear a threshold. For a low-carbon concrete that performs 20% better than the UNICEM collective sheet, break-even is often reached on a single major public contract.
Read the source article: EPD or FDES for France: which to publish, and at what cost?