Crate energy_billing 

Pure multi-product retail energy billing for German markets.

Architecture

This crate is the commercial billing engine for the Lieferant (LF). It answers: “What does the customer’s invoice look like?”

metering       — "What quantities are billable?"
    ↓
eeg-billing    — "What EEG remuneration applies?" (NB-side)
    ↓
energy-billing — "What does the customer's invoice look like?" (LF-side)
    ↓
accountingd    — Payments, Ledger, Dunning

Primary API — Product::build_engine

use energy_billing::{BillingContext, BillingPeriod, GridInput, InvoiceType, MeterInput, Product, Quantities, RegulatoryRates};
use rust_decimal::dec;
use time::macros::date;

let json = r#"{"category":"STROM","arbeitspreis_ct_per_kwh":"30.0","grundpreis_ct_per_day":"8.0"}"#;
let product: Product = serde_json::from_str(json).unwrap();
let ctx = BillingContext {
    malo_id:         "51238696012".to_owned(),
    lf_mp_id:        "9900000000001".to_owned(),
    rechnungsnummer: "R2026-001".to_owned(),
    period: BillingPeriod::new(date!(2026-01-01), date!(2026-01-31)).unwrap(),
    invoice_type:     InvoiceType::Initial,
    contract_id:      None,
    regulatory_rates: RegulatoryRates::default(),
    ..Default::default()
};
let quantities = Quantities {
    electricity: Some(MeterInput { arbeitsmenge_kwh: dec!(500), ..Default::default() }),
    ..Default::default()
};
let invoice = product.build_engine(&GridInput::default(), &RegulatoryRates::default())
    .bill(ctx, &quantities).unwrap();
assert!(invoice.brutto_eur > invoice.netto_eur);

Product categories

Category	Provider	Legal basis
STROM	ElectricityProvider	§41 EnWG
WAERMEPUMPE	ControllableLoadProvider (§14a)	§14a EnWG
WALLBOX	ControllableLoadProvider (§14a)	§14a EnWG
GAS	GasProvider	§41 EnWG
WAERME	HeatProvider	§41 EnWG; AVBFernwärmeV §24; CO2KostAufG §3; §14 WPG
WASSER	WaterProvider	AVBWasserV; §12 Abs. 2 Nr. 1 UStG (7 %); gesplittete Abwassergebühr
SOLAR	SolarProvider	§42a Abs. 4 EnWG (Mieterstrom-Preisdeckel) / §42b EnWG (GGV)
EEG	EegProvider (→ eeg-billing)	§§20–21 EEG 2023
EINSPEISUNG	EinspeisungProvider	§20 EEG 2023
HEMS	HemsProvider	—
EMOBILITY	EmobilityProvider	§41a EnWG
ENERGIEDIENSTLEISTUNG	ServiceProvider	—
STROM + dynamic_epex=true	DynamicElectricityProvider	§41a EnWG
SHARING	ElectricityProvider + EnergyShareProvider	§42c EnWG

Re-exports

pub use context::AbschlagDeduction;

pub use context::BillingContext;

pub use context::BillingPeriod;

pub use context::CustomerKategorie;

pub use context::InvoiceType;

pub use context::Rechnungsempfaenger;

pub use context::SettlementForm;

pub use context::Verbraucherinformationen;

pub use context::Verbrauchshistorie;

pub use context::Vertragsart;

pub use context::Vertragsinformationen;

pub use engine::BillingEngine;

pub use error::EngineError;

pub use invoice::Invoice;

pub use invoice::TaxSubtotal;

pub use invoice::VatCategory;

pub use invoice::negate_rechnung_json_for_correction;

pub use invoice::tax_subtotals_of;

pub use position::BillingPosition;

pub use position::BillingWarning;

pub use position::PositionCategory;

pub use position::PositionTrace;

pub use position::WarningSeverity;

pub use provider::BillingProvider;

pub use provider::MTU_MINUTES;

pub use provider::mtu_start;

pub use quantities::Ablesungsart;

pub use quantities::Abschlagsplan;

pub use quantities::AbschlagsplanEntry;

pub use quantities::Absetzung;

pub use quantities::AbsetzungsGrund;

pub use quantities::DayApportionment;

pub use quantities::DynamicInterval;

pub use quantities::EegMeterInput;

pub use quantities::EmobilityMeterInput;

pub use quantities::EnergyShareMeterInput;

pub use quantities::GasMeterInput;

pub use quantities::GgvNutzungsplan;

pub use quantities::GgvNutzungsplanEntry;

pub use quantities::GgvSolarInput;

pub use quantities::GridInput;

pub use quantities::HemsMeterInput;

pub use quantities::MeterInput;

pub use quantities::MeteringMode;

pub use quantities::ProsumerMeterInput;

pub use quantities::Quantities;

pub use quantities::Sect14aModul3Verbrauch;

pub use quantities::Sect41aAnnualComparison;

pub use quantities::ServiceMeterInput;

pub use quantities::SolarMeterInput;

pub use quantities::WaermeMeterInput;

pub use quantities::WasserMeterInput;

pub use rates::ERDGAS_UMRECHNUNGSFAKTOR_GJ_PER_MWH;

pub use rates::RegulatoryRates;

pub use rates::RoundMoney;

pub use rates::behg_ct_per_kwh_for_year;

pub use rates::behg_ct_per_kwh_from_price;

pub use rates::energiesteuer_gas_for_year;

pub use rates::erdgas_emissionsfaktor_kg_per_kwh;

pub use rates::mwst_rate_for_gas_waerme_period;

pub use rates::mwst_rate_for_period;

pub use rates::round_money;

pub use rates::steuer_stichtage_im_zeitraum;

pub use rates::stromsteuer_for_year;

pub use steuer::EnergiesteuerBefreiung;

pub use steuer::EnergiesteuerTarif;

pub use steuer::Steuerentlastung;

pub use steuer::StromsteuerBefreiung;

pub use steuer::StromsteuerErmaessigung;

pub use steuer::StromsteuerTarif;

pub use tariff::AbwasserRegime;

pub use tariff::BlockTierInput;

pub use tariff::ControllableLoadProduct;

pub use tariff::EegProduct;

pub use tariff::EinspeisungProduct;

pub use tariff::ElectricityProduct;

pub use tariff::EmobilityProduct;

pub use tariff::EnergieQuellen;

pub use tariff::GasProduct;

pub use tariff::HeatProduct;

pub use tariff::HemsProduct;

pub use tariff::IndexedPriceConfig;

pub use tariff::Product;

pub use tariff::SeasonalPriceOverride;

pub use tariff::ServiceProduct;

pub use tariff::SharingProduct;

pub use tariff::SolarProduct;

pub use tariff::WaterProduct;

pub use providers::ControllableLoadProvider;

pub use providers::DynamicElectricityProvider;

pub use providers::EegProvider;

pub use providers::EinspeisungProvider;

pub use providers::ElectricityProvider;

pub use providers::EmobilityProvider;

pub use providers::EnergyShareProvider;

pub use providers::GasProvider;

pub use providers::HeatProvider;

pub use providers::HemsProvider;

pub use providers::MwStProvider;

pub use providers::ServiceProvider;

pub use providers::SolarProvider;

pub use providers::WaterProvider;

Modules

context

BillingContext — the immutable billing metadata passed to every provider.

engine

BillingEngine — the composition root for multi-product invoice generation.

error

EngineError — the typed error surface of the billing engine.

invoice

Invoice — the aggregate root of every billing run.

position

BillingPosition — the atomic unit of every energy invoice.

provider

The BillingProvider trait — one implementation per product type.

providers

Concrete BillingProvider implementations for all product types.

quantities

Quantities — all metered quantities for one billing period.

rates

RegulatoryRates — statutory levy rates, operator-configured.

steuer

Verbrauchsteuerliche Begünstigungen — Befreiung, Ermäßigung, Entlastung.

tariff

Typed product definitions for the German retail energy market.

Structs

Amount

Fixed-point monetary amount with P decimal places.

Enums

BillingError

All errors produced by the billing engine.

RoundingStrategy

Explicit rounding strategy. Always required — no hidden defaults.

Type Aliases

EuroAmount

A monetary amount in euro at 10⁻⁵-EUR resolution.