Crate metering 

German energy-metering quantities: exact, cited, and calendar-correct.

A pure library — no I/O, no async, no clock — for the quantities German metering is settled on. Every quantity is a Decimal, every rounding names its places and mode (precision), and every rule cites the clause it implements. It computes kWh, m³ and kW, not money.

Time is Europe/Berlin. A DayBoundary — Strom at 00:00, Gas at 06:00 — names days, months and years as UTC Periods of their real length (23, 24 or 25 hours a day). Interval data enters as MeterIntervals, validated once into a Series — sorted, on one grid, one channel — which the rest of the crate consumes.

Quick start

Aggregate a series into the quantities a billing period is invoiced on:

use metering::prelude::*;
use time::{Duration, macros::date};

let day = DayBoundary::Strom.day(date!(2026 - 06 - 01)).unwrap();
let slots = (0..96)
    .map(|i| MeterInterval::quarter_hour(day.start() + Duration::minutes(15 * i), dec!(1), QualityFlag::Measured))
    .collect::<Result<Vec<_>, _>>()?;
let series = Series::new(Resolution::QUARTER_HOUR, DayBoundary::Strom, slots)?;

let period = aggregate(&series, day)?;
assert_eq!(period.arbeitsmenge, dec!(96));            // kWh
assert_eq!(period.spitzenleistung_kw, Some(dec!(4))); // 1 kWh in 15 min
assert_eq!(period.coverage.pct(), Some(dec!(100)));

Validate, then substitute — a missing quarter-hour is an error finding, and a gap up to 2 h is interpolated between validated measured values:

use metering::prelude::*;
use metering::time::holiday::Bundesland;
use metering::vee::substitute::{Method, SubstitutionReason};
use metering::vee::validation::Grade;
use time::{Duration, macros::{date, datetime}};

let day = DayBoundary::Strom.day(date!(2026 - 06 - 01)).unwrap();
let kwh = |i: i64| Decimal::new(200 + i, 3); // a ramp, 0.200 … 0.295 kWh
let slots = (0..96)
    .filter(|i| *i != 50) // one quarter-hour never arrived
    .map(|i| MeterInterval::quarter_hour(day.start() + Duration::minutes(15 * i), kwh(i), QualityFlag::Measured))
    .collect::<Result<Vec<_>, _>>()?;
let series = Series::new(Resolution::QUARTER_HOUR, DayBoundary::Strom, slots)?;

let rules = Rules::strom(day, datetime!(2026-07-01 0:00 UTC), None);
let report = validate(&series, &rules);
assert_eq!(report.grade(), Grade::C);

let policy = Policy::strom(Bundesland::Be, SubstitutionReason::CommunicationFailure);
let filled = substitute(&series, &report, &policy)?;
assert_eq!(filled.substitutes[0].method, Method::Interpolation);
assert_eq!(filled.substitutes[0].value, dec!(0.25)); // between 0.249 and 0.251
assert_eq!(validate(&filled.series, &rules).grade(), Grade::A);

The Gastag and gas conversion — a gas day runs 06:00 to 06:00 local, and a metered volume becomes kWh_Hs through Brennwert and Zustandszahl:

use metering::gas::conversion::gas_m3_to_kwh_hs;
use metering::prelude::*;
use time::macros::{date, datetime};

let gastag = DayBoundary::Gas.day(date!(2026 - 01 - 15)).unwrap();
assert_eq!(gastag.start(), datetime!(2026-01-15 5:00 UTC));
// The Gastag across the autumn change is 25 hours long.
assert_eq!(DayBoundary::Gas.day(date!(2026 - 10 - 24)).unwrap().duration().whole_hours(), 25);

// 100 m³ × 11.2 kWh/m³ × 0.95
assert_eq!(gas_m3_to_kwh_hs(dec!(100), dec!(11.2), dec!(0.95)), Some(dec!(1064.000)));

Features

serde adds Serialize/Deserialize to the coded enums, identifiers, inputs and most results, and enables time/serde; the covered types and wire representation are under Design.

Modules

Group	Modules
Series, time, IDs	series (intervals, Series, readings, resampling), time (calendar, holidays, resolution), ids (MaLo, MeLo, EIC, BDEW codes, OBIS)
VEE	vee — validation and grading, substitute values, Messtyp
Billing	billing — aggregation, Zählzeiten, reactive energy, imbalance, losses, forecast
SLP	slp — strom (BDEW SLP), gas (SigLinDe)
Gas, heat	gas (DVGW G 685 conversion), heat (HeizkostenV)
Grid	grid — § 14a EnWG, Ausfallarbeit, EN 50160, rollout
Allocation	allocation — UTILTS Berechnungsformel, § 42b community, § 42c sharing, sessions
EEG	eeg — MiSpeL, EEG § 51/§ 51a, EnFG § 46
Cross-cutting	precision (every rounding), error, prelude

Start with the guides; the design constraints and regulatory basis are the reference for rules and sources.

Re-exports

pub use error::ParseError;

pub use ids::obis::ObisCode;

pub use ids::MaloId;

pub use ids::MeloId;

pub use series::Series;

pub use series::interval::Direction;

pub use series::interval::MeterInterval;

pub use series::interval::QualityFlag;

pub use series::interval::Sparte;

pub use series::interval::Unit;

pub use time::calendar::DayBoundary;

pub use time::calendar::Period;

pub use time::resolution::Resolution;

Modules

allocation

Allocation between metering points: the UTILTS Berechnungsformel, the § 42b community allocation, § 42c energy sharing and charging sessions.

billing

Billing quantities: Arbeitsmenge and Spitzenleistung, tariff registers, reactive energy, imbalance, network losses and the annual forecast.

eeg

EEG and EnFG quantities: negative-price quarter-hours, Zeitgleichheit, and the BNetzA MiSpeL Festlegung for storage and charge points.

error

ParseError — the single error type every FromStr in this crate returns, so one ? chain decodes a row:

gas

Gas: volume-to-energy conversion per DVGW G 685.

grid

Grid operation: § 14a EnWG control, Redispatch 2.0 Ausfallarbeit, EN 50160 power quality and the MsbG smart-meter rollout.

heat

Heat and warm water: HeizkostenV.

ids

Market identifiers: MaLo/MeLo-IDs, EIC, BDEW codes, Regelzonen and OBIS codes.

precision

Every rounding in the crate: decimal places and mode, in one table.

prelude

The common pipeline in one import: the core nouns, the entry points from readings to a billing period, and Decimal with its dec! literal.

series

The metered time series: MeterInterval, the validated Series, register readings and resampling.

slp

Standard load profiles: BDEW SLP Strom and SigLinDe SLP Gas.

time

Europe/Berlin time: the calendar (DayBoundary, Period), statutory holidays and interval resolutions.

vee

Validation, estimation and editing on a validated Series.