Crate grid_billing 

Role-neutral grid invoice calculation for German energy market billing.

Covers all DSO/TSO-side INVOIC documents:

• NNE (Netznutzungsentgelt) — PIDs 31001, 31005, 31011
• MMM (Mehr-/Mindermengensaldo) — PID 31002
• MSB (Messstellenbetrieb) — PID 31009
• Selbst ausgestellte Rechnung — PID 31006 (LF acting as NB)

Used by both the NB (netzbilanzd) to generate invoices and the LF (invoicd) to self-issue invoices under §20 MessZV. The formula is identical for both roles — only who initiates differs.

Generates GridInvoice domain objects from meter readings and tariff data. The service layer (netzbilanzd, invoicd) converts GridInvoice to rubo4e::current::Rechnung via a local into_rechnung() helper — keeping BO4E as a service-layer concern. The generated invoices are:

• PID 31001 — MMM-Rechnung NNE Strom (NB → LF, monthly network usage)
• PID 31002 — MMM-Stornorechnung NNE Strom (NB → LF, correction/reversal)
• PID 31005 — MMM-Rechnung NNE Gas (NB → LF, monthly gas NNE)
• PID 31006 — MMM-selbst ausgestellte Rechnung (LF selbstausstellt, same formula)

Design

• Pure library — zero I/O, zero async. All calculations are deterministic.
• No floating-point money — uses EuroAmount (i64 × 10⁻⁵ EUR) for all monetary arithmetic to avoid rounding errors.
• Self-validating — all generated invoices satisfy invoic-checker checks 1–3 (period validity, position arithmetic, document total) by construction. Check 4–5 (tariff deviation) depends on the PreisblattStore supplied by the caller.
• BO4E-free output — returns GridInvoice (pure domain type). The service layer (netzbilanzd, invoicd) owns the rubo4e::current::Rechnung conversion via a local into_rechnung() helper. This keeps grid-billing publishable to crates.io without pulling in the internal rubo4e crate.

Example

use grid_billing::{NneInput, calculate_nne_invoice};
use rust_decimal::Decimal;
use time::macros::date;

fn d(s: &str) -> Decimal { Decimal::from_str_exact(s).unwrap() }

let result = calculate_nne_invoice(&NneInput {
    malo_id: "51238696780".into(),
    nb_mp_id: "9900357000004".into(),
    lf_mp_id: "9900012345678".into(),
    rechnungsnummer: "NNE-2025-001".into(),
    period_from: date!(2025-01-01),
    period_to:   date!(2025-01-31),
    invoice_date: date!(2025-02-15),
    due_date: date!(2025-03-15),
    arbeitsmenge_kwh: d("1500"),
    arbeitspreis_ct_per_kwh: d("3.5"),
    arbeitsmenge_ht_kwh: None,
    arbeitspreis_ht_ct_per_kwh: None,
    arbeitsmenge_nt_kwh: None,
    arbeitspreis_nt_ct_per_kwh: None,
    spitzenleistung_kw: None,
    leistungspreis_eur_per_kw: None,
    ka_satz_ct_per_kwh: Some(d("0.11")),
}).expect("valid billing input");

Re-exports

pub use billing::calculate_mmm_invoice;

pub use billing::calculate_msb_invoice;

pub use billing::calculate_nne_invoice;

pub use error::BillingError;

pub use types::GridInvoice;

pub use types::InvoicePosition;

pub use types::MmmInput;

pub use types::MsbInput;

pub use types::NneInput;

pub use types::QuantityUnit;

Modules

billing

NNE, MMM, and MSB invoice generation logic.

error

Error types for mako-nne.

types

Input/output types for the billing calculation functions.