HECTOR programme | Technical transparency
Methodology & Baseline
Understand the assumptions behind the carbon figures, the baseline used for each VPA, and the documents that support them.
Which methodology do the reports use?
The reviewed VPA1 and VPA2 monitoring reports reference Gold Standard’s Emission Reductions from Safe Drinking Water Supply, version 1.0. The calculation compares the emissions associated with obtaining safe drinking water in the baseline scenario with project emissions and applicable leakage.
The official methodology page now provides version 2.0 and a Paris Agreement alignment notice for vintage 2026 issuances. The version referenced in a historical monitoring report is not necessarily the version applicable to a future issuance. Applicability depends on the project documents and transition rules for each VPA and issuance period.
Read Gold Standard’s methodology and update notice (new tab)
What does fNRB mean?
fNRB is the fraction of non-renewable biomass. For woody biomass fuel in the baseline, it represents the fraction established as non-renewable. It is an input to the baseline emission calculation, not a measurement of household reach, water quality or issued credits.
MoFuSS (Modelling Fuelwood Saving Scenarios) provides model-derived inputs for assessing fuelwood use and non-renewability. VPA2’s monitoring report attributes its 25% fNRB value to MoFuSS. This value relates to the project boundary and reporting period described in that report.
25% does not mean that 25% of treated water, households or carbon credits are verified. It is not a universal value for all HECTOR activities.
Explore the MoFuSS source referenced in the report (new tab)
Baseline values by VPA and period
VPA1 / GS13130
80% in the reviewed historical reports
Monitoring period 1: 17 May 2024 – 31 January 2025.
Monitoring period 2: 1 February 2025 – 28 October 2025.
The reports document an 80% fNRB value based on CDM Tool 30, version 4.0. The period 2 report states that this value applies until 31 December 2025 and describes a change in the permitted basis from 1 January 2026.
Sources: T-PerfCert_V1.1-Monitoring-Report-Clean.pdf, printed p. 36; GS13130-Monitoring-Report.pdf, printed pp. 51-52.
VPA2 / GS23337
25% in the reviewed monitoring report
Monitoring period 1: 2 June 2025 – 31 December 2025.
The report lists a 25% fNRB value derived from MoFuSS in parameter SDWS 21. Its baseline calculation also uses 25%. This is a report-specific input, not a claim of issued credits or automatic certification.
The 25% value relates to this monitoring period and project boundary, rather than a universal baseline for all HECTOR activities.
Source: GS23337_Monitoring-Report.pdf, printed pp. 50 and 69.
How the calculation is built
This simplified guide follows the calculation framework in the reviewed version 1.0 reports. It is not a replacement for the applicable methodology or the project calculation workbook.
- Baseline inputs. The baseline includes water-treatment practices, fuel mix, stove efficiencies, emission factors and the applicable fNRB input. Survey results and energy-weighted fuel shares represent different measures.
- Eligible water quantity. The methodology applies monitored-water and consumption-limit rules alongside water-quality and usage evidence. Total sensor throughput alone is not a credit calculation.
- Baseline emissions. Eligible water quantity and the baseline emission factor determine baseline emissions, subject to the corrections and limits of the applicable methodology.
- Project emissions and leakage. Project emissions and applicable leakage are deducted under the methodology. Their values depend on the project inputs and reporting period.
- Reporting and registry records. Period-specific workbooks and monitoring reports document the calculation. Reported reductions, verification status and issued credits are separate records.
Emission reductions = baseline emissions – project emissions – leakage emissions
The reviewed reports express this as ERy = BEy – PEy – LEy, in tonnes of CO2 equivalent for the reporting year. The VPA2 report also applies Qy = min(Qm,y, Qpop,y) to determine the water quantity used under Method 1.
Source: GS23337_Monitoring-Report.pdf, printed pp. 68-69 and 75.
From monitoring reports to registry records
Monitoring reports describe the VPA, reporting period, methodology and calculation assumptions. Monitoring-report results, verified results, issued credits and retired credits are different measures. A report upload does not, by itself, establish certification.
View the project registry, document library and transaction history
Source review date: . This summary explains historical monitoring reports; it is not a certification decision or a new carbon-credit estimate.
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