Methodology

Each plant is registered under one of two rule sets. Verra VMR0017 v1.0 (23 April 2026), the demo plants' methodology, is applied with ACM0002 v22.0 as it requires: hydro of 15 MW or less in Least Developed Countries, VT0008 additionality (a ±10% sensitivity table and a ±50% capacity band), EF_Res 100 kg CO₂e/MWh and embodied-emission leakage. The CDM rules (AMS-I.D v18.0 up to 15 MW, ACM0002 above) remain available; Verra inactivates them as standalone methodologies on 1 January 2027. TOOL03 prices fossil fuel burnt on site. The grid factor follows TOOL07 v7.0 for CDM plants and Verra's VT0011 v1.0 revision of it for VMR0017 plants (build margin over all units, hydro weights 0.4 / 0.6). The same integer arithmetic runs in this app, in the MCP server and inside the HydroVmr0017Module contract, and shared test vectors keep them identical.

Emission reductions

ER_y  = BE_y − PE_y − LE_y
BE_y  = EG_PJ,y × EF_grid,CM,y          rounded down
PE_y  = PE_FF,y + PE_HP,y               rounded up
PE_FF = Σ FC × NCV × EF_CO2             TOOL03, IPCC upper bounds
PE_HP = EF_Res × TEG_y                  if 4 < PD ≤ 10 W/m², else 0
                                        EF_Res = 100 kg CO2e/MWh (VMR0017), 90 (CDM)
LE_y  = EG × EF_embodied                VMR0017 §8.3, 21 g CO2e/kWh for hydro,
                                        EG_facility (greenfield) or
                                        max(EG_PJ, EG_facility × Cap_add / Cap_PJ)
LE_y  = 0                               CDM; VMR0017 retrofit
EG_PJ,y = EG_facility,y                        greenfield
EG_PJ,y = EG_facility,y − (EG_historical + σ)  retrofit, addition
          per crediting year, cumulatively; 0 after DATE_BaselineRetrofit
EG_facility = export − import at the grid meter, after QA/QC

Negative periods are carried forward and netted against later issuance. Sub-kilogram remainders carry too, so no rounding ever creates a credit.

Monitoring QA/QC (conservative by construction)

  • Replayed, out-of-order or overlapping intervals reject the period (double counting).
  • Gaps are credited as zero; coverage below 90% needs review, and the contract enforces the same floor.
  • Main vs check meter beyond their combined accuracy: the lower reading is used.
  • Expired calibration: export × (1 − MPE), import × (1 + MPE).
  • Export above gross generation is never credited.
  • Generation above nameplate or above ρ·g·Q·H·ηmax credits the interval as zero; more than 20% such intervals reject the period.
  • Water-to-wire efficiency outliers (modified z-score ≥ 3.5) go to review.
  • Water quality is a safeguard: it can send a period to review but never changes the quantity.

TOOL07 on the demo grid: Illustrative interconnected grid

An illustrative grid, not a real country. simple OM, 3-year generation-weighted (2023, 2024, 2025); the LCMR share averages 34.6%, under the 50% the simple OM requires. EF_EL per unit below is for 2025, IPCC lower bounds.

UnitSourceSinceEG 2025 (MWh)OptionEF_EL (t/MWh)BM sample
COAL-1other-bituminous-coal19965,200,000A20.9476
COAL-2other-bituminous-coal20094,800,000A10.9091
COAL-3sub-bituminous-coal20162,100,000A20.928
CCGT-1natural-gas20123,600,000A20.3759
OCGT-1natural-gas2017600,000A20.5749
DIESEL-1gas-diesel-oil2014250,000A10.7454
HFO-1residual-fuel-oil2019420,000A20.6795
CCGT-2natural-gas20241,900,000A20.3554
HYDRO-1hydro19857,500,000LCMR0
HYDRO-2hydro2021900,000LCMR0
WIND-1wind2022650,000LCMR0
SOLAR-1solar2023480,000LCMR0
SOLAR-2solarCDM2020300,000LCMR0

HYDRO-DEMO-01 · Demo run-of-river plant

VMR0017 v1.0eligible

Power densityNo new or enlarged reservoir (A_PJ = A_BL): PE_HP,y = 0
EF_grid,CM0.109606 t/MWh → registered 109,606 g/MWh (rounded down)
TOOL03 COEFGas/diesel oil: 43.3 GJ/t × 74,800 kg/TJ = 3.23884 t/t
LeakageVMR0017 §8.3: LE_y = EG_facility,y × EF_embodied (21 g CO2e/kWh for hydropower)
AdditionalityVT0008: regulatory surplus; project IRR 8.1% without and 12.4% with carbon revenue against a 11.5% benchmark; F = 16.7%, not common practice; §5.4.2(2)(b)–(c) met (CCP-eligible); assessor: none (illustrative demo data, not validated)
Crediting2026-01-01 → 2032-12-30 (7 × 365 days)
Registered on-chain
{
  "projectType": 0,
  "methodology": 1,
  "hostCountry": "UG",
  "capacityKw": 500,
  "baselineCapacityKw": 0,
  "reservoirAreaM2": 0,
  "baselineReservoirAreaM2": 0,
  "authorizedCapacityKw": 0,
  "efGridGPerMwh": 109606,
  "fuelCoefGPerTonne": 3238840,
  "baselineWh": 0,
  "baselineEndsAt": 0,
  "creditingStart": 1767225600,
  "creditingEnd": 1987977600,
  "registrationRequestedAt": 1777852800,
  "designHash": "0xee688a1b509e57ddb0d5c9487b92057ceab410447d384c5d72bf36717b715af9"
}

HYDRO-DEMO-02 · Demo storage plant

VMR0017 v1.0eligible

Power density4 < PD = 6.67 W/m² ≤ 10: PE_HP,y = EF_Res (100 kg/MWh) × TEG_y
EF_grid,CM0.109606 t/MWh → registered 109,606 g/MWh (rounded down)
TOOL03 COEFGas/diesel oil: 43.3 GJ/t × 74,800 kg/TJ = 3.23884 t/t
LeakageVMR0017 §8.3: LE_y = EG_facility,y × EF_embodied (21 g CO2e/kWh for hydropower)
AdditionalityVT0008: regulatory surplus; project IRR 8.1% without and 12.4% with carbon revenue against a 11.5% benchmark; F = 16.7%, not common practice; §5.4.2(2)(b)–(c) met (CCP-eligible); assessor: none (illustrative demo data, not validated)
Crediting2026-03-01 → 2033-02-27 (7 × 365 days)
Registered on-chain
{
  "projectType": 0,
  "methodology": 1,
  "hostCountry": "UG",
  "capacityKw": 12000,
  "baselineCapacityKw": 0,
  "reservoirAreaM2": 1800000,
  "baselineReservoirAreaM2": 0,
  "authorizedCapacityKw": 0,
  "efGridGPerMwh": 109606,
  "fuelCoefGPerTonne": 3238840,
  "baselineWh": 0,
  "baselineEndsAt": 0,
  "creditingStart": 1772323200,
  "creditingEnd": 1993075200,
  "registrationRequestedAt": 1777852800,
  "designHash": "0x8d035d3f77c199677d561d2d7bddd5a62962f826ad11978f950752df486c4ebf"
}

Conservative IPCC bounds

IPCC 2006 Vol. 2 Ch. 1 defaults, 95% interval. The baseline (TOOL07) takes the lower bound, project emissions (TOOL03) the upper bound, so neither side can inflate credits.

FuelNCV GJ/t (low / high)CO₂ kg/TJ (low / high)
Crude oil40.1 / 44.871,100 / 75,500
Motor gasoline42.5 / 44.867,500 / 73,000
Gas/diesel oil41.4 / 43.372,600 / 74,800
Residual fuel oil39.8 / 41.775,500 / 78,800
Liquefied petroleum gases44.8 / 52.261,600 / 65,600
Natural gas46.5 / 50.454,300 / 58,300
Anthracite21.6 / 32.294,600 / 101,000
Other bituminous coal19.9 / 30.589,500 / 99,700
Sub-bituminous coal11.5 / 2692,800 / 100,000
Lignite5.5 / 21.690,900 / 115,000

What the contract enforces on its own

  • Power density rule at registration (PD ≤ 4 W/m² reverts) and the PE_HP rate that follows from it.
  • Baseline fields per project type, grid EF range, crediting span of exactly 5, 7 or 10 × 365 days.
  • Periods inside the crediting period, inside one crediting year, never overlapping.
  • Gross generation within nameplate × duration; net export never above gross.
  • VMR0017 plants: at most 15 MW; EF_Res and EF_embodied fixed by the registered methodology.
  • BE, PE_HP, PE_FF, LE and ER recomputed from monitored inputs; credits minted from the carried balance.
  • A per-plant sequence number, so a report computed against a stale ledger cannot be attested (StaleLedger).

Not implemented: VT0011's annual build-margin update, TOOL07 option B, dispatch-data and ex-post OM, off-grid plants and imports, integrated hydro projects, battery and pumped storage, geothermal sources. The LDC and VT0008 conditions are checked at design assessment from recorded evidence; a VVB validates the design and the additionality, and this is a digital implementation of the equations, not a certification.

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