metering

The open, checkable reference for German energy-metering quantities, in Rust. Every number traces to a published clause — MsbG, EnWG, EEG, HeizkostenV, the BNetzA Festlegungen, the EDI@Energy documents — and every quoted passage is checked against the PDF it comes from.

A pure library — no I/O, no async, no clock. Quantities are exact Decimals, every rounding names its places and mode, and time is Europe/Berlin: a day of 23, 24 or 25 hours, a Gastag from 06:00. It computes kWh, m³ and kW, not money.

Guides · API reference · Changelog

Install

cargo add metering
cargo add metering --features serde   # wire formats for the inputs, codes and results

The serde feature enables serde and time/serde; see Design for the representation. MSRV 1.88 (edition 2024), tested in CI; raising it is a minor-version bump while 0.x.

Quick start

A day of quarter-hours with one value missing: validate, substitute, aggregate.

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

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // The Liefertag 1 June 2026, 00:00 to 00:00 Europe/Berlin, as a UTC period.
    let day = DayBoundary::Strom.day(date!(2026 - 06 - 01)).unwrap();

    // 96 quarter-hours of 0.5 kWh, except slot 50, which never arrived.
    let slots = (0..96)
        .filter(|i| *i != 50)
        .map(|i| {
            let from = day.start() + Duration::minutes(15 * i);
            MeterInterval::quarter_hour(from, dec!(0.5), QualityFlag::Measured)
        })
        .collect::<Result<Vec<_>, _>>()?;
    let series = Series::new(Resolution::QUARTER_HOUR, DayBoundary::Strom, slots)?;

    // Validate: the gap is an error finding, so the grade is C.
    let rules = Rules::strom(day, datetime!(2026-07-01 0:00 UTC), None);
    let report = validate(&series, &rules);
    assert_eq!(report.grade(), Grade::C);

    // Substitute: a gap up to 2 h is interpolated (STS+Z32 code Z92).
    let policy = Policy::strom(Bundesland::Be, SubstitutionReason::CommunicationFailure);
    let filled = substitute(&series, &report, &policy)?;
    assert_eq!(filled.substitutes[0].code, Some("Z92"));

    // Aggregate: Arbeitsmenge and Spitzenleistung of the billed day.
    let period = aggregate(&filled.series, day)?;
    assert_eq!(period.arbeitsmenge, dec!(48));
    assert_eq!(period.spitzenleistung_kw, Some(dec!(2)));
    Ok(())
}

examples/pipeline.rs runs the whole chain — readings, validation, substitution, aggregation, tariff registers — on the 25-hour autumn day: cargo run --example pipeline.

What's in it

Scope

The regulatory basis lists every source and the version in force. Nothing here is legal advice.

Testing

just ci          # the CI gate: fmt, clippy, purity, tests, docs, example, package, deny
just references  # fetch the primary sources the citations are checked against
just quotes      # check every quoted German passage against those PDFs

The Rust blocks in this README and on the guide pages run as doctests. just quotes needs pdftotext and the fetched corpus; it is not a CI job.

Contributing and license

Issues and pull requests welcome; a change to a regulated calculation cites the provision it implements. Licensed under Apache-2.0 or MIT at your option.