CO₂ Transport Mode Comparison — ConformaESG Integration Service

Every SupplierPurchaseRecord automatically calculates transport emissions when transport_method, distance_km, and related weight fields are provided. This recipe shows how to leverage that calculation to compare modes side-by-side and justify transport choices in ESG reports.

Emission Factor Formula

Shell

CO₂ (kg) = factor × distance_km × (weight_kg / 1000)

Transport Mode	Emission Factor	Unit
`ROAD`	0.000096	kg CO₂ / (tonne · km)
`SEA`	0.000011	kg CO₂ / (tonne · km)
`AIR`	0.000602	kg CO₂ / (tonne · km)
`RAIL`	0.000028	kg CO₂ / (tonne · km)

1. Create One Record per Transport Mode

Use the same shipment parameters for all four records so the comparison is apples-to-apples. Here: 500 kg fabric from India to Italy, 7 200 km.

Shell
1curl -X POST "http://localhost:8080/api/v1/purchases?userId=1" \
-H "Content-Type: application/json" \
-d '{
  "supplier_id": 42,
  "supplier_product_id": 17,
  "purchase_date": "2026-03-01T08:00:00",
  "quantity_kg": 500.0,
  "transport_method": "ROAD",
  "distance_km": 7200,
  "batch_number": "COMP-ROAD-2026-03"
}'

Shell
1curl -X POST "http://localhost:8080/api/v1/purchases?userId=1" \
-H "Content-Type: application/json" \
-d '{
  "supplier_id": 42,
  "supplier_product_id": 17,
  "purchase_date": "2026-03-01T08:00:00",
  "quantity_kg": 500.0,
  "transport_method": "SEA",
  "distance_km": 7200,
  "batch_number": "COMP-SEA-2026-03"
}'

Shell
1curl -X POST "http://localhost:8080/api/v1/purchases?userId=1" \
-H "Content-Type: application/json" \
-d '{
  "supplier_id": 42,
  "supplier_product_id": 17,
  "purchase_date": "2026-03-01T08:00:00",
  "quantity_kg": 500.0,
  "transport_method": "AIR",
  "distance_km": 7200,
  "batch_number": "COMP-AIR-2026-03"
}'

Shell
1curl -X POST "http://localhost:8080/api/v1/purchases?userId=1" \
-H "Content-Type: application/json" \
-d '{
  "supplier_id": 42,
  "supplier_product_id": 17,
  "purchase_date": "2026-03-01T08:00:00",
  "quantity_kg": 500.0,
  "transport_method": "RAIL",
  "distance_km": 7200,
  "batch_number": "COMP-RAIL-2026-03"
}'

2. Results at a Glance

The API returns emissions data in every 201 Created response. For the scenario above (7 200 km, 500 kg):

Transport Mode	CO₂ Emissions	vs. SEA baseline
`SEA`	0.0396 kg	baseline
`RAIL`	0.1008 kg	+155%
`ROAD`	0.3456 kg	+773%
`AIR`	2.1672 kg	+5 373%

Note

Sea freight emits ~55× less CO₂ than air for the same route. When lead time allows, sea is the default recommended choice for intercontinental textile shipments.

3. Python: Automate the Comparison

Python
1import requests
2
3BASE_URL = "http://localhost:8080"
4
5def compare_transport(supplier_id: int, product_id: int,
                    distance_km: float, weight_kg: float,
                    purchase_date: str = "2026-03-01T08:00:00"):
  modes   = ["ROAD", "SEA", "AIR", "RAIL"]
  results = []
10
  for mode in modes:
      resp = requests.post(
          f"{BASE_URL}/api/v1/purchases?userId=1",
          json={
              "supplier_id":         supplier_id,
              "supplier_product_id": product_id,
              "purchase_date":       purchase_date,
              "quantity_kg":         weight_kg,
              "transport_method":    mode,
              "distance_km":         distance_km,
              "batch_number":        f"COMP-{mode}-AUTO",
          }
      ).json()
      results.append((mode, resp.get("transport_emissions_tco2", 0)))
25
  results.sort(key=lambda x: x[1])
  print(f"\nCO₂ comparison — {distance_km} km, {weight_kg} kg\n")
  print(f"{'Mode':<8} {'CO₂ (kg)':>12}  {'vs best':>10}")
  print("-" * 34)
  baseline = results[0][1]
  for mode, co2 in results:
      ratio = f"+{((co2 / baseline) - 1) * 100:.0f}%" if co2 != baseline else "baseline"
      print(f"{mode:<8} {co2:>12.4f}  {ratio:>10}")
34
35compare_transport(
  supplier_id=42,
  product_id=17,
  distance_km=7200,
  weight_kg=500
40)

4. Cancel Comparison Records

Comparison records are created with status ORDERED by default. Cancel them immediately if they were only created for analysis purposes.

Shell
1for id in 201 202 203 204; do
2  curl -X PATCH "http://localhost:8080/api/v1/purchases/$id?userId=1" \
3    -H "Content-Type: application/json" \
4    -d '{ "purchase_status": "CANCELLED" }'
5done

Warning

If you use batch_number values in comparison records, choose unique names (e.g. COMP-SEA-2026-03) so they do not conflict with real production batches. batch_number must be unique per supplier_id.