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Dairy Manure Biogas Yield

Anaerobic digester · IPCC 2019 Tier-2 · EPA AgSTAR 3rd ed · LCFS avoided-baseline credit

IPCC 2019 Tier-2 method
Estimates anaerobic-digester biogas / methane / pipeline-RNG yield from a dairy herd, sizes the digester (HRT-based volume), and computes the avoided-baseline-lagoon CH₄ credit used in CARB LCFS pathway scoring. Defaults: VS = 9.2 kg/(1000 kg·d), B₀ = 0.24 m³/kg VS (IPCC 2019 Refinement Vol 4 Ch 10 NA dairy), baseline lagoon MCF = 0.76 (Warm Temp Moist).

Herd Composition

head
head
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kg
kg

Excretion & B₀

kg/(1000kg·d)
IPCC 2019 Refinement Table 10.13a — NA dairy = 9.2; ASABE D384.2 site-specific preferred.
m³/kg VS
IPCC 2019 Table 10.16a NA dairy = 0.24 ±15%; site-specific BMP preferred.
%
EPA AgSTAR: 50% pasture / 85–95% freestall + flush.

Digester Configuration

%
Fraction of B₀ realized; presets per AgSTAR / Metcalf & Eddy 5e Ch 10.
°C
days

Biogas, Leakage & LCFS

%
Dairy biogas typical 55–65%.
%
IPCC 2019 Table 10.17 AD leakage range: 1% best-practice → 13% open-storage.
%
—
IPCC 2019 Table 10.17 / CARB LCFS Tier 1: 0.50 cool → 0.76 warm-temp → 0.80 tropical.
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Engineering Basis

  • VS × B₀ × η_digester: IPCC 2019 Refinement Vol 4 Ch 10 §10.4.2 Tier-2 method.
  • Default constants: VS = 9.2 kg/(1000kg·d) (Table 10.13a NA), B₀ = 0.24 m³/kg VS (Table 10.16a NA, ±15%).
  • Digester η presets: covered lagoon 65% / plug-flow 80% / CSTR mesophilic 88% / CSTR thermophilic 92% — EPA AgSTAR Handbook 3rd ed (EPA 430-B-20-001, 2020) + Metcalf & Eddy 5e.
  • LCFS avoided-baseline: counterfactual = uncovered anaerobic lagoon emitting CH₄ at MCF × B₀ (IPCC 2019 Table 10.17, range 0.50–0.80 over climate zones).
  • Digester sizing: V = Q_manure × HRT (HRT-based; vendor / CFD design for FID).
  • Standards: IPCC 2019 Refinement, EPA AgSTAR 3e, ASABE D384.2, 40 CFR 98 Subpart JJ, CARB LCFS §95488.

Learn the Theory

Understand biogas production pathways, feedstock composition, methane yield models, and RNG potential from dairy manure

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