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Accounting Academy

MODULE 1: Fundamentals

MODULE 2: Calculations

MODULE 3: Batch Partitioning & LCA

MODULE 4: Mass Balance with Ledgers

MODULE 5: Integration Testing

MODULE 6: Advanced Patterns & Production

Documentation Index

Fetch the complete documentation index at: https://docs.mangrovesystems.com/llms.txt

Use this file to discover all available pages before exploring further.

What you’ll learn in this lesson:
  • Understand why emissions must be allocated to individual batches
  • Apply proportional allocation (by mass or carbon content)
  • Apply time-based allocation for periodic costs
  • Use direct allocation for batch-specific emissions
In the previous lesson you learned how to calculate total process emissions. But those totals need to be distributed across individual batches — a monthly electricity bill must be shared among all the deliveries that month. This lesson covers the three main allocation methods.

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Why allocation is necessary

Batches are the reporting unit — each batch must carry its fair share of emissions so that its net carbon figure is accurate. Without allocation, you’d have:
  • Some batches with zero emissions (overstated removal)
  • Other batches bearing all emissions (understated removal)
  • Reports that don’t reflect the true per-batch impact

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Allocation methods

Distribute emissions based on a measurable attribute of each batch — typically mass or carbon content.Formula: batch_emissions = total_emissions × (batch_attribute / sum_of_all_batch_attributes)Example — by mass: Monthly electricity = 4.17 tCO2e. Three deliveries: 3t, 5t, 2t (total 10t).
  • Batch 1: 4.17 × (3/10) = 1.25 tCO2e
  • Batch 2: 4.17 × (5/10) = 2.09 tCO2e
  • Batch 3: 4.17 × (2/10) = 0.83 tCO2e
Best for: Shared resources consumed in proportion to production volume (electricity, facility overhead).

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Combining allocation methods

In practice, you’ll use multiple methods for different emission sources within the same project:
Emission SourceAllocation MethodRationale
Monthly electricityProportional (by mass)Electricity consumption scales with production volume
Monthly propaneProportional (by mass)Heating energy scales with throughput
Transport emissionsDirect (per-delivery)Each delivery has its own transport route and distance
Embodied emissionsTime-based (monthly amortization)Facility costs are constant regardless of production
The allocation method should reflect the causal relationship between the emission source and the batch. If an emission scales with mass, allocate by mass. If it’s tied to a specific event, allocate directly.

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Building allocation in the model

In the Model Editor, allocation logic is implemented using operators and node references:
1

Calculate total emissions per source

Sum all emission events for the accounting period (e.g., total kWh × grid factor).
2

Calculate the allocation weight

For proportional allocation: batch_mass / total_mass_in_period. This may use the data_point_proportion operator.
3

Apply the allocation

Multiply total emissions by the allocation weight to get the per-batch share.
4

Deduct from gross carbon

Use a difference node: net_carbon = gross_carbon - allocated_emissions.
The data_point_proportion operator in the Model Editor can automatically calculate a batch’s share of a total. This simplifies proportional allocation — you don’t need to manually compute the denominator.

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Verifying allocation correctness

After building the allocation logic, verify that:
  1. Allocated emissions sum to the total — all per-batch shares should add up to the total emissions for the period
  2. No batch has negative net carbon — if a batch’s emissions exceed its gross carbon, something is likely misconfigured
  3. Proportions are reasonable — larger batches should receive proportionally larger emission shares
A common error is double-counting: allocating the same emission source through both proportional and direct methods. Each emission source should be allocated through exactly one method.

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Check your understanding

Use proportional allocation for shared resources that scale with production volume (electricity, facility overhead). Use direct allocation for emissions uniquely tied to a specific batch (transport for a specific delivery, batch-specific processing). The choice should reflect the causal relationship between the emission and the batch.
Check three things: (1) Allocated emissions sum to the total — all per-batch shares should equal the total period emissions. (2) No batch has negative net carbon — if emissions exceed gross carbon, the allocation is likely wrong. (3) Proportions are reasonable — larger batches should carry proportionally larger emission shares.
You’re now ready to put batch partitioning and LCA into practice in the Module 3 Exercise: Configure Batch Partitioning with LCA Emissions.