---
title: "Calculate fNAV economics: avoided CAPEX, annual fee, payback (Phase 5)"
method: POST
path: "/api/finance-agent/fnav/economics"
tags: ["Netzfahrplan / fNAV"]
---

# Calculate fNAV economics: avoided CAPEX, annual fee, payback (Phase 5)

`POST /api/finance-agent/fnav/economics`

## Request

- Base URL: `https://api.cernion.de`
- URL: `https://api.cernion.de/api/finance-agent/fnav/economics`
- Auth: none declared

Deterministic fNAV economics assessment. Computes:
- avoidedCopperCapexEur: cost of conventional grid expansion avoided by fNAV
- annualFeeEur: recurring cost of the fNAV contract
- paybackYears: avoidedCapex / annualFee
- sensitivityFlags: qualitative flags for high uncertainty inputs

Option B: calls eog-calculator.capexEstimate for TOTEX-based CAPEX reference; if unavailable, uses parametric fallback (FN_ECONOMICS_PARTIAL).

Governance Option B: governanceStatus is always requires_governance_decision until legalStatus=approved AND contractStatus=signed.

## Query parameters

- `token` string

## Request body

- object
  - `fnavProfile` object, required
    - `requestedCapacity` number, required: Requested capacity kW
    - `firmCapacity` number
    - `flexibleCapacity` number
    - `curtailmentWindow` number
    - `signalPriorityPolicy` string
    - `controlEvidenceRef` string
    - `contractStatus` string
    - `legalStatus` string
  - `voltageLevel` 'NS' | 'MS' | 'HS'
  - `gridOperator` string: Used for eog-calculator lookup
  - `annualFeeEur` number: Annual fNAV contract fee (EUR/yr)
  - `ownerContact` string
  - `avoidedCapexOverrideEur` number: Override avoided CAPEX (EUR)
  - `token` string: Optional Cernion MCP token for this request. Overrides CERNION_TOKEN when provided.

## Response `200`

fNAV economics result

- object
  - `avoidedCopperCapexEur` number
  - `annualFeeEur` number
  - `paybackYears` number
  - `capexSource` 'eog_calculator' | 'parametric_fallback' | 'override'
  - `sensitivityFlags` string[]
  - `governanceStatus` string
  - `governanceBlockers` string[]
  - `contractGate` object: Explicit contract-gate assessment
  - `governanceArtifact` object, nullable
  - `decisionChain` object[]
  - `proof` object
  - `findings` object[]
  - `metadata` object

---

[API](https://skmtc.dev/cernion/apis/cernion-energy-tools-api.md) · [All operations](https://skmtc.dev/cernion/apis/cernion-energy-tools-api/llms.txt) · [OpenAPI document](https://skmtc.dev/cernion/apis/cernion-energy-tools-api/revisions/cdb94473b538?raw)