Reconciled 2026-08-13 against the portfolio financial model’s re-base: this worksheet’s program series, contracted floors, and cost rows are unchanged by it. The re-base adjusted SPV sell-through pricing and financing mechanics, which this worksheet does not use.
Sensor-monitored borehole repair across five arid counties, with carbon revenue committed to keeping the pumps running.
This program restores water access during drought; it does not treat water quality. That distinction decides what this page will and will not claim.
A defensible pathway from borehole uptime to averted DALYs in drought-affected ASAL counties has not yet been designed. Publishing one anyway would be false precision, so v1 declines to.
What the program can honestly claim today: measured service outcomes, climate value, and a financing mechanism that converts credits into pump maintenance. The evidence-adjustment pipeline is not applied because no health effect size is modeled; both facts are stated in the workbook so the omission cannot be reintroduced silently.
| Series | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | 2031 | 2032 | 2033 | Total |
|---|---|---|---|---|---|---|---|---|---|---|
| Net credits (tCO₂e) | 0 | 26,124 | 8,882 | 14,804 | 22,205 | 29,607 | 29,607 | 29,607 | 29,607 | 190,443 |
| Buy price to partner ($/cr) | 9.20 | 9.20 | 9.30 | 9.50 | 9.60 | 9.70 | 9.80 | 9.90 | 9.90 | — |
| Sell price, channel ($/cr) | 15 | 15 | 18 | 19 | 20 | 25 | 30 | 30 | 30 | — |
| Virridy purchases ($) | 0 | 149,325 | 241,977 | 533,862 | 670,493 | 809,863 | 951,952 | 961,666 | 961,666 | 5,280,804 |
| Partner upside share, 30% ($) | 0 | 28,242 | 67,910 | 160,159 | 217,910 | 383,223 | 588,656 | 585,742 | 585,742 | 2,617,584 |
| Implied population (credits ÷ the 0.087 yield in use) | — | 157,583 | 252,612 | 545,592 | 678,087 | 810,592 | 943,087 | 943,087 | 943,087 | — |
Updated 24 September 2026: the crediting basis on this page is the yield in use in the portfolio model, adopted 20 August 2026 from the independent due diligence reconstruction under Gold Standard SDWS V2.0. It replaces the yield this worksheet carried in August, and the credit series, cost per tonne and integrity-adjusted cost per tonne are recomputed on it.
Credits and prices are proforma inputs (Voluntary channel 2025–26, CORSIA/LDC from 2027; Mortenson contracted offtake 147,440 credits 2027–33 is the floor case, scenario S1). Yield in use is 0.087 credits per person-year, adopted 20 August 2026 from the independent due diligence reconstruction; the annex previously carried the 0.103 DHS-anchored bottom-up value. Flagged: the implied population ramp from 158K to 943K people is a proforma assumption; the verified current reach is 120,000 people across 200 sites.
| USAID BHA installation grant | $2,000,000 | installed the boreholes' sensors and repair platform the credits monitor; included so maintenance-only costs are never claimed against full-system benefits |
| Guaranteed first batch (2026) | $210,000 | MIN(credits, 7,000) × $30, once |
| Credit purchases, 2025–2033 | $5,280,804 | credits × buy price, per year above |
| TOTAL_PROGRAMME_COST | $7,490,804 | Formula single denominator; the build fails if any figure divides by anything else |
| Person-years served | 5,273,728 | credits ÷ 0.103; cost per person-year $1.42 |
| $ / tonne, cost basis | $39.33 | $7,490,804 ÷ 190,443 t · 4.7× below the $185 social cost of carbon |
| Credit integrity ratio | 0.765 | baseline residual 0.85 (flagged, V2.0 bottom-up, DHS-anchored) × uptime delivery 0.90 (sensor-measured) × leakage 1.0 |
| $ / tonne, integrity-adjusted | $51.41 | 3.6× below the SCC |
| Partner-side carbon revenue, 2025–33 | $8,108,389 | purchases + 30% upside share + first batch |
| Maintenance financing (70%) | $5,675,872 | the program's committed use of carbon revenue |
| Maintenance per person-year, steady state | $1.14 | 0.70 × $15.86 partner revenue per credit × 0.103 credits per person-year; computed at matched population, not the 120,000 current-reach figure |
| Scenario | Credits | $/t cost basis | $/t integrity-adj | Maint $/person-yr | Reading |
|---|---|---|---|---|---|
| Base case | 190,443 | $39.33 | $51.41 | $1.14 | expanded-demand base |
| S1 · contracted-only (Mortenson 147,440) | 147,440 | $24.70 | $32.29 | $0.71 | the floor case; still 7.5× below the SCC |
| S2 · voluntary $10 backstop | 190,443 | $39.33 | $51.41 | $0.71 | cost side unchanged; maintenance financing thins |
| S3 · uptime 0.75 | 190,443 | $39.33 | $61.45 | $0.95 | integrity falls to 0.64; still 3.0× below the SCC |
| Dimension | Rating | Assessment |
|---|---|---|
| Effect-size quality | No health effect size is modeled, deliberately. The service outcomes are measured program data, not modeled effects. Designing a defensible drought-access to health pathway, or formally declining one, is the v2 gate. | |
| Counterfactual robustness | The observed counterfactual is the program's own baseline: 56% functionality and 214-day repairs under government-only maintenance. Carbon-side, the Mortenson offtake is philanthropic demand; a commercial replacement developer is less plausible at this yield. | |
| Moral-weight transparency | Not applicable in v1: no units of value are computed. Stated so the omission cannot be reintroduced silently. | |
| Attribution and integrity | Installation was USAID-funded; the carbon layer finances maintenance. The cost basis therefore includes the $2M grant rather than claiming maintenance-only costs against full-system benefits. | |
| Excluded factors | Excluded: any health valuation (by design), sensor replacement capex beyond the grant, NDMA co-financing (would lower Virridy-attributable cost), and the flagged population ramp. | |
| Ranking stability | The climate finding is stable: the worst scenario is $24.70 per tonne, 7.5× below the SCC. The fragile number is maintenance financing per person-year, which halves at the $10 voluntary backstop. |