AMS-III.D Methane Recovery Workflow

cdmAmsIIId Package

Introduction

AMS-III.D covers methane recovery from animal manure management systems. This vignette demonstrates how cdmAmsIIId operationalises the methodology with tidyverse data structures. We simulate digesters, verify applicability, walk through equation-level helpers, and complete the monitoring workflow.

Applicability Checks

We begin by simulating monitoring data and running the three applicability helpers.

monitoring <- simulate_ams_iiid_dataset(n_farms = 2, n_periods = 4, seed = 2025)

tibble::tibble(
  system = check_applicability_system_type_iiid(monitoring, group_cols = "farm_id")$system_type_applicable,
  frequency = check_applicability_measurement_frequency_iiid(monitoring, group_cols = "farm_id")$measurement_frequency_applicable,
  controls = check_applicability_leakage_control_iiid(monitoring, group_cols = "farm_id")$leakage_controls_applicable
) |>
  tidyr::pivot_longer(everything(), names_to = "criterion", values_to = "applicable") |>
  quiet_kable(caption = "Applicability outcomes for each AMS-III.D criterion")
#> Warning: 'xfun::attr()' is deprecated.
#> Use 'xfun::attr2()' instead.
#> See help("Deprecated")
Applicability outcomes for each AMS-III.D criterion
criterion applicable
system TRUE
frequency TRUE
controls FALSE
system TRUE
frequency TRUE
controls TRUE

Simulated Dataset

The simulated dataset provides methane generation parameters and monitoring metadata for each period.

head(monitoring) |>
  quiet_kable(caption = "Excerpt of simulated AMS-III.D monitoring data")
#> Warning: 'xfun::attr()' is deprecated.
#> Use 'xfun::attr2()' instead.
#> See help("Deprecated")
Excerpt of simulated AMS-III.D monitoring data
farm_id monitoring_period year month days_in_period volatile_solids_kg_per_day methane_potential_m3_per_kg_vs baseline_mcf_fraction project_mcf_fraction capture_efficiency_fraction destruction_efficiency_fraction methane_recovered_m3 leakage_emissions_tco2e system_type measurements_per_month leakage_controls_in_place
farm_01 1 2024 1 30 38.25897 0.2358604 0.7973926 0.5953660 0.8152952 0.9744679 6825.638 0.0302362 anaerobic lagoon 9 TRUE
farm_01 2 2024 2 30 35.18712 0.2484258 0.8208835 0.5479459 0.9151712 0.9672106 6780.003 0.0269570 uncovered digester 11 TRUE
farm_01 3 2024 3 30 39.05906 0.2352516 0.7343653 0.5632880 0.9083011 0.9527681 7162.925 0.0291299 anaerobic lagoon 10 FALSE
farm_01 4 2024 4 30 41.68057 0.2189394 0.9214510 0.6020286 0.8499133 0.9698346 7241.613 0.0309192 liquid slurry store 11 TRUE
farm_02 1 2024 1 30 36.94762 0.2349484 0.7877715 0.5847947 0.8394437 0.9827634 6697.171 0.0285704 anaerobic lagoon 7 TRUE
farm_02 2 2024 2 30 34.14501 0.2491789 0.8366893 0.6289050 0.8278704 0.9742211 6901.316 0.0301146 uncovered digester 9 TRUE

Equation Walkthrough

Equation helpers operate on tidy tables and can be combined sequentially. We aggregate to the farm level for clarity.

aggregated <- aggregate_monitoring_periods_iiid(monitoring, group_cols = "farm_id")

baseline <- calculate_baseline_methane_emissions_iiid(aggregated, group_cols = "farm_id")
project <- calculate_project_methane_emissions_iiid(aggregated, group_cols = "farm_id")
recovered <- calculate_recovered_methane_iiid(aggregated, group_cols = "farm_id")
leakage <- calculate_leakage_emissions_iiid(aggregated, group_cols = "farm_id")

list(
  Baseline = baseline,
  Project = project,
  Recovered = recovered,
  Leakage = leakage
) |>
  purrr::imap_dfr(~ dplyr::mutate(.x, component = .y), .id = NULL) |>
  dplyr::relocate(component) |>
  quiet_kable(caption = "Equation-level outputs across components")
#> Warning: 'xfun::attr()' is deprecated.
#> Use 'xfun::attr2()' instead.
#> See help("Deprecated")
Equation-level outputs across components
component farm_id baseline_emissions_tco2e project_emissions_tco2e recovered_methane_tco2e leakage_emissions_tco2e
Baseline farm_01 66.65810 NA NA NA
Baseline farm_02 66.57075 NA NA NA
Project farm_01 NA 7.399157 NA NA
Project farm_02 NA 7.680403 NA NA
Recovered farm_01 NA NA 507.6419 NA
Recovered farm_02 NA NA 522.9936 NA
Leakage farm_01 NA NA NA 0.1172423
Leakage farm_02 NA NA NA 0.1192977

Monitoring Period Aggregation

When working with period-level data, use aggregate_monitoring_periods_iiid() to roll up flows while averaging coefficients.

aggregate_monitoring_periods_iiid(monitoring, group_cols = "farm_id") |>
  quiet_kable(caption = "Aggregated monitoring data by farm")
#> Warning: 'xfun::attr()' is deprecated.
#> Use 'xfun::attr2()' instead.
#> See help("Deprecated")
Aggregated monitoring data by farm
farm_id volatile_solids_kg_per_day methane_recovered_m3 leakage_emissions_tco2e days_in_period methane_potential_m3_per_kg_vs baseline_mcf_fraction project_mcf_fraction capture_efficiency_fraction destruction_efficiency_fraction
farm_01 154.1857 28010.18 0.1172423 120 0.2346193 0.8185231 0.5771571 0.8721702 0.9660703
farm_02 142.7575 28491.09 0.1192977 120 0.2436492 0.8501690 0.6113661 0.8580228 0.9784856

Meta-Function

The meta-function composes equation helpers to produce emission reductions in a single call.

reductions <- estimate_emission_reductions_ams_iiid(
  baseline_data = monitoring,
  project_data = monitoring,
  recovery_data = monitoring,
  leakage_data = monitoring,
  group_cols = "farm_id"
)

reductions |>
  quiet_kable(caption = "Net emission reductions from AMS-III.D workflow")
#> Warning: 'xfun::attr()' is deprecated.
#> Use 'xfun::attr2()' instead.
#> See help("Deprecated")
Net emission reductions from AMS-III.D workflow
farm_id emission_reductions_tco2e
farm_01 522.2207
farm_02 537.5060

Function Reference 

reference <- tibble::tribble(
  ~Function, ~Signature, ~Purpose,
  "check_applicability_system_type_iiid", "(data, system_type_col, allowed_types, group_cols)", "Validate manure system eligibility.",
  "check_applicability_measurement_frequency_iiid", "(data, frequency_col, minimum_frequency, group_cols)", "Confirm monitoring frequency requirements.",
  "check_applicability_leakage_control_iiid", "(data, control_indicator_col, group_cols)", "Ensure leakage controls are documented.",
  "calculate_baseline_methane_emissions_iiid", "(data, volatile_solids_col, methane_potential_col, methane_conversion_factor_col)", "Baseline methane emissions.<br>\\(BE_y = \\sum_i VS_{i,y} \\times B0_{i,y} \\times MCF^{BL}_{i,y} \\times d_{i,y} \\times \\rho_{CH4} \\times GWP_{CH4}\\)",
  "calculate_project_methane_emissions_iiid", "(data, project_methane_conversion_factor_col, capture_efficiency_col)", "Project methane emissions.<br>\\(PE_y = \\sum_i \\big(VS_{i,y} \\times B0_{i,y} \\times MCF^{PR}_{i,y} - DEST_{i,y}\\big) \\times \\rho_{CH4} \\times GWP_{CH4}\\)",
  "calculate_recovered_methane_iiid", "(data, methane_recovered_col, destruction_efficiency_col)", "Destroyed methane from recovery.<br>\\(DEST_y = \\sum_i MREC_{i,y} \\times DE_{i,y} \\times \\rho_{CH4} \\times GWP_{CH4}\\)",
  "calculate_leakage_emissions_iiid", "(data, leakage_col)", "Leakage totals.<br>\\(LE_y = \\sum_i LE_{i,y}\\)",
  "calculate_emission_reductions_iiid", "(baseline, project, recovered, leakage, group_cols)", "Net emission reductions.<br>\\(ER_y = (BE_y - PE_y) - LE_y\\)",
  "aggregate_monitoring_periods_iiid", "(data, group_cols, sum_cols, mean_cols)", "Roll up monitoring periods.<br>\\(ER_{p,y} = (BE_{p,y} - PE_{p,y}) - LE_{p,y}\\)",
  "estimate_emission_reductions_ams_iiid", "(baseline_data, project_data, recovery_data, leakage_data, group_cols)", "Meta-estimator for AMS-III.D.<br>\\(ER_y = (BE_y - PE_y) - LE_y\\)"
)

quiet_kable(reference, escape = FALSE)
#> Warning: 'xfun::attr()' is deprecated.
#> Use 'xfun::attr2()' instead.
#> See help("Deprecated")
Function Signature Purpose
check_applicability_system_type_iiid (data, system_type_col, allowed_types, group_cols) Validate manure system eligibility.
check_applicability_measurement_frequency_iiid (data, frequency_col, minimum_frequency, group_cols) Confirm monitoring frequency requirements.
check_applicability_leakage_control_iiid (data, control_indicator_col, group_cols) Ensure leakage controls are documented.
calculate_baseline_methane_emissions_iiid (data, volatile_solids_col, methane_potential_col, methane_conversion_factor_col) Baseline methane emissions.
BEy=∑iVSi,y×B0i,y×MCFi,yBL×di,y×ρCH4×GWPCH4BE_y = \sum_i VS_{i,y} \times B0_{i,y} \times MCF^{BL}_{i,y} \times d_{i,y} \times \rho_{CH4} \times GWP_{CH4}
calculate_project_methane_emissions_iiid (data, project_methane_conversion_factor_col, capture_efficiency_col) Project methane emissions.
PEy=∑i(VSi,y×B0i,y×MCFi,yPR−DESTi,y)×ρCH4×GWPCH4PE_y = \sum_i \big(VS_{i,y} \times B0_{i,y} \times MCF^{PR}_{i,y} - DEST_{i,y}\big) \times \rho_{CH4} \times GWP_{CH4}
calculate_recovered_methane_iiid (data, methane_recovered_col, destruction_efficiency_col) Destroyed methane from recovery.
DESTy=∑iMRECi,y×DEi,y×ρCH4×GWPCH4DEST_y = \sum_i MREC_{i,y} \times DE_{i,y} \times \rho_{CH4} \times GWP_{CH4}
calculate_leakage_emissions_iiid (data, leakage_col) Leakage totals.
LEy=∑iLEi,yLE_y = \sum_i LE_{i,y}
calculate_emission_reductions_iiid (baseline, project, recovered, leakage, group_cols) Net emission reductions.
ERy=(BEy−PEy)−LEyER_y = (BE_y - PE_y) - LE_y
aggregate_monitoring_periods_iiid (data, group_cols, sum_cols, mean_cols) Roll up monitoring periods.
ERp,y=(BEp,y−PEp,y)−LEp,yER_{p,y} = (BE_{p,y} - PE_{p,y}) - LE_{p,y}
estimate_emission_reductions_ams_iiid (baseline_data, project_data, recovery_data, leakage_data, group_cols) Meta-estimator for AMS-III.D.
ERy=(BEy−PEy)−LEyER_y = (BE_y - PE_y) - LE_y

Workflow Overview 

overview <- tibble::tribble(
  ~Step, ~Description, ~Function,
  "1", "Generate or collect monitoring data by period.", "simulate_ams_iiid_dataset()",
  "2", "Confirm system eligibility, monitoring frequency, and leakage controls.", "check_applicability_*_iiid()",
  "3", "Aggregate monitoring periods to the reporting unit.", "aggregate_monitoring_periods_iiid()",
  "4", "Apply equation helpers to compute baseline, project, recovered, and leakage emissions.", "calculate_*_iiid()",
  "5", "Compose results into emission reductions.", "estimate_emission_reductions_ams_iiid()"
)

quiet_kable(overview, caption = "High-level AMS-III.D workflow")
#> Warning: 'xfun::attr()' is deprecated.
#> Use 'xfun::attr2()' instead.
#> See help("Deprecated")
High-level AMS-III.D workflow
Step Description Function
1 Generate or collect monitoring data by period. simulate_ams_iiid_dataset()
2 Confirm system eligibility, monitoring frequency, and leakage controls. check_applicability_*_iiid()
3 Aggregate monitoring periods to the reporting unit. aggregate_monitoring_periods_iiid()
4 Apply equation helpers to compute baseline, project, recovered, and leakage emissions. calculate_*_iiid()
5 Compose results into emission reductions. estimate_emission_reductions_ams_iiid()