metering

Gas, units and load profiles

m³ to kWh_Hs per DVGW G 685, the Zustandszahl, unit normalisation that refuses to guess, and the standard load profiles: BDEW SLP Strom and SigLinDe SLP Gas.

m³ → kWh_Hs

kWh_Hs = V_Betrieb [m³] × Hs [kWh/m³] × Zustandszahl (DVGW G 685). Billing a derived value rests on § 25 Nr. 4 and Nr. 7 MessEV — see the regulatory basis.

use metering::gas::conversion::{GasConversionParams, gas_m3_to_kwh_hs, normalize_to_kwh};
use rust_decimal::dec;

// 100 m³ × 10.55 kWh/m³ × 0.9764, exactly.
assert_eq!(gas_m3_to_kwh_hs(dec!(100), dec!(10.55), dec!(0.9764)), Some(dec!(1030.102000)));

// Through the unit-aware path: a volume needs both parameters, and has no default.
let params = GasConversionParams::new(dec!(10.55), dec!(0.98));
assert_eq!(normalize_to_kwh(dec!(100), "m3", Some(&params), None).unwrap(), dec!(1033.900));
assert!(normalize_to_kwh(dec!(100), "m3", None, None).is_err());

Pass a Betriebsvolumen (OBIS 7-0:3.0.0). A Normvolumen (7-0:13.2.0) is already state-converted; use GasConversionParams::already_converted(hs), which fixes the Zustandszahl at 1. GasConversionParams has no Default.

The Zustandszahl

From the Netzbetreiber's Höhenzonen table, or computed from the DVGW G 685-3 inputs: air pressure (p_amb = 1016 − 0,12 × H), Effektivdruck, Abrechnungstemperatur (15 °C) and Kompressibilitätszahl (1 below one bar). Normzustand per DIN 1343: 273,15 K, 1013,25 mbar.

use metering::gas::conversion::{
    G685Rounding, ZustandszahlParams, gas_m3_to_kwh_hs_rounded, hoehenzonen_luftdruck_mbar, zustandszahl,
};
use metering::precision::G685_STRATEGY;
use rust_decimal::dec;

// A household connection 253 m above sea level, 22 mbar Effektivdruck.
let params = ZustandszahlParams::below_one_bar(hoehenzonen_luftdruck_mbar(dec!(253)).unwrap(), dec!(22)).unwrap();
let z = zustandszahl(&params).unwrap();
assert_eq!(z.round_dp_with_strategy(4, G685_STRATEGY), dec!(0.9427));

let kwh = gas_m3_to_kwh_hs_rounded(dec!(1874), dec!(11.316), z, G685Rounding::PUBLISHED_PRACTICE).unwrap();
assert_eq!(kwh.round_dp_with_strategy(2, G685_STRATEGY), dec!(19991.07));

The final rounding is a setting: Merkblätter diverge between whole kWh and two decimals. G685Rounding::PUBLISHED_PRACTICE rounds the Zustandszahl to four and the Brennwert to three places and leaves the result unrounded.

Unit normalisation

normalize_to_kwh(value, unit, gas, interval_secs): an energy unit is rescaled exactly, a power needs its averaging interval, a volume the gas parameters; an unknown unit is an error.

use metering::gas::conversion::normalize_to_kwh;
use rust_decimal::dec;

assert_eq!(normalize_to_kwh(dec!(3.6), "GJ", None, None).unwrap(), dec!(1000));
assert_eq!(normalize_to_kwh(dec!(48), "kW", None, Some(900)).unwrap(), dec!(12));
assert!(normalize_to_kwh(dec!(1), "furlong", None, None).is_err());

SLP Strom

The BDEW profiles are value tables the operator loads — the 2025 revision (H25, G25, L25, P25, S25) or the 1999 VDEW profiles; the crate ships none. BDEW Hinweise zu den aktualisierten Standardlastprofilen Strom (17.03.2025): "Jedem Netzbetreiber steht es weiterhin frei, bei der Bilanzierung auf die aktualisierten Profile aus dem Jahr 2025, die alten Profile aus dem Jahr 1999, eigene Profile oder eine Mischung der verschiedenen Optionen zurückzugreifen."

DynamicSlpProfile::value_at(instant, &calendar) resolves the Berlin quarter-hour, month, day type in the Land and Dynamisierung, and answers None when a table is missing.

  • Day type from SlpCalendar: 24 and 31 December take the Saturday profile unless a Sunday (VDEW definition; eves_as_saturday(false)).
  • Dynamisierung: Dynamization::BDEW, the H0/H25 quartic in exact Decimal, refused outside day 1..=366.
use metering::slp::strom::{DynamicSlpProfile, Dynamization, LoadProfile, SlpDayType};
use metering::time::holiday::{Bundesland, SlpCalendar};
use rust_decimal::dec;
use time::macros::datetime;

let mut h25 = DynamicSlpProfile::new(LoadProfile::H25).dynamization(Dynamization::BDEW);
h25.insert(6, SlpDayType::SonnFeiertag, vec![dec!(100); 96]).unwrap();

// Fronleichnam 2026 is a holiday in Bavaria, a Werktag in Berlin.
let noon = datetime!(2026-06-04 10:00 UTC);
assert!(h25.value_at(noon, &SlpCalendar::new(Bundesland::By)).is_some());
assert!(h25.value_at(noon, &SlpCalendar::new(Bundesland::Be)).is_none()); // Werktag table not loaded

SLP Gas — SigLinDe

One value per Gastag from temperature — Leitfaden Abwicklung von Standardlastprofilen Gas (KoV XV, Stand 27.03.2026, Anlage 6):

h(ϑ)  = A / (1 + (B / (ϑ − ϑ₀))^C) + D  +  max{ mH·ϑ + bH ; mW·ϑ + bW }
Q(D)  = Kundenwert · h(ϑ_allok) · F_WT
ϑ_allok = (ϑ_D + 0,5·ϑ_D−1 + 0,25·ϑ_D−2 + 0,125·ϑ_D−3) / 1,875

use metering::slp::gas::{SigLinDe, allocation_temperature, gas_daily_quantity};
use rust_decimal::dec;

// The Leitfaden's worked example: −0,2399 °C.
let theta = allocation_temperature(dec!(-2.0), dec!(0.5), dec!(3.4), dec!(3.6)).unwrap();
assert_eq!(theta, dec!(-0.23991));

let h = SigLinDe::DE_HEF34.h_value(dec!(4)).unwrap();
let q = gas_daily_quantity(dec!(60.3423), h, dec!(1)).unwrap();
assert!(q > dec!(90));

h_value evaluates the sigmoid in f64 (the one float crossing) and returns an unrounded Decimal, as Anlage 5 requires. SigLinDe::DE_HEF34 is embedded to verify against the printed numbers; operators load the sets they balance with. The allocation-temperature weights use four decimals, rounded mathematisch (half to even).