einsd Operator Guide

einsd is the Einspeiser Registry and EEG/KWKG Settlement daemon. It manages the full lifecycle of decentralised renewable feed-in plants under the EEG (all versions 2000–2023+) and CHP plants under the KWKG, covering 12 settlement models on the ten formula schemes eeg-billing implements, and all generation technology types.

Two German terms recur throughout. Einspeisevergütung is the fixed feed-in tariff the Netzbetreiber (NB — the grid operator) pays for electricity delivered into its grid. Direktvermarktung is the alternative: the operator sells the electricity on the market itself and the NB tops it up with a Marktprämie, the gap between a statutory reference value and the market price. Which of the two a plant is on is its Veräußerungsform (§ 21b EEG 2023), and it decides both the formula and the paperwork.

Settlement arithmetic is implemented in the separate eeg-billing library crate — zero floating-point money, fully unit-tested, no I/O. The library is EEG-version-aware: it enforces the correct §51/§52/§53 rules for each plant based on its eeg_gesetz year and technology type, respecting Bestandsschutz for old plants commissioned before 2016.

graph TB
    Operator["NB Operator / ERP"]
    edmd["edmd :8380<br/>¼h Einspeisung feed-in<br/>(GET /api/v1/energy/{malo_id}?direction=EINSPEISUNG)"]
    einsd["einsd :9180"]
    eeg_billing["eeg-billing crate<br/>10 settlement schemes<br/>Anlage 1 Marktprämie<br/>§49 degression · §36h Abs.1/2 wind<br/>§51 Negativpreis · §51a Förderende<br/>§51b biogas Ausschreibung<br/>§39i Biogas-Höchstanteile<br/>§52 Abs.6 netting<br/>SettlementPeriodState · InbetriebnahmeTyp<br/>no I/O"]
    db[("PostgreSQL<br/>eeg_anlagen · settlement_receipts<br/>settlement_receipt_history<br/>settlement_state_transitions<br/>eeg_regionalnachweise · eeg_stromsteuerbefreiungen<br/>eeg_sect54_solar_defekte · eeg_pflichtverstoesse<br/>marktwert_preise · epex_monthly_prices · epex_spot_prices<br/>wind_guetefaktor_reevaluations · eeg_verguetungssaetze")]
    erp["ERP webhook<br/>CloudEvents 1.0"]
    agentd["agentd :9580<br/>eeg-agent<br/>(all de.eeg.* events)"]

    Operator -->|"POST /anlagen"| einsd
    Operator -->|"POST /mastr-registrierung"| einsd
    Operator -->|"POST /repowering"| einsd
    Operator -->|"POST /zusammenlegen"| einsd
    Operator -->|"POST /switch-veraeusserungsform"| einsd
    Operator -->|"PUT /api/v1/epex-spot"| einsd
    Operator -->|"POST /anlagen/{tr}/wind-reevaluation"| einsd
    Operator -->|"POST /settle/{year}/{month}"| einsd
    Operator -->|"POST /anlagen/{tr}/settlements/{y}/{m}/correction"| einsd
    einsd --> eeg_billing
    einsd <-->|"¼h feed-in × EPEX spot (§51)"| edmd
    einsd -->|"persist receipts<br/>settlement state"| db
    einsd -->|"de.eeg.verguetung.berechnet<br/>de.eeg.marktpraemie.berechnet<br/>de.eeg.anlage.mastr-registriert<br/>de.eeg.veraeusserungsform.gewechselt"| erp
    einsd -->|"de.eeg.anlage.foerderung-auslaufend<br/>de.eeg.settlement.batch-due"| agentd

Port: :9180

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Why einsd Exists

German EEG/KWKG law requires every Netzbetreiber (NB) — the grid operator, one of the four market roles alongside the Lieferant (LF, supplier), the Messstellenbetreiber (MSB, metering point operator) and the Bilanzkreisverantwortlicher (BKV, balance-group responsible party) — to:

1. Register every feed-in plant with its commissioning date, capacity, applicable tariff, and governing EEG version — immutable for 20 years under EEG or fixed term under KWKG.
2. Verify MaStR registration before releasing Vergütung payments (§52 EEG 2023 / old §47 EEG 2021 via §100 Übergangsregelung).
3. Calculate monthly remuneration per the applicable settlement model and EEG version.
4. Enforce the §51 Negativpreisregel version that governs each plant — keyed on the commissioning date, because the Solarspitzengesetz rewrote §51 mid-year on 25.02.2025; Bestandsanlagen keep their original rules.
5. Alert the asset owner ≥180 days before the Förderendedatum.
6. Emit CloudEvents to the ERP system for payment dispatch and accounting entries.

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EEG Version-aware Architecture

Every plant has an eeg_gesetz column that carries the version-year-dependent rules — the §52 Pflichtverstoß regime and the §100 Übergangsbestimmungen. The eeg-billing library exposes an EegGesetz enum (8 variants) for it:

EegGesetz::Kwkg       — KWKG plants (no EEG §52 rules)
EegGesetz::Eeg2000    — EEG 2000 plants
EegGesetz::Eeg2004    — EEG 2004 plants
EegGesetz::Eeg2009    — EEG 2009 plants
EegGesetz::Eeg2012    — EEG 2012 + 2014 amendment plants
EegGesetz::Eeg2017    — EEG 2017 plants (commissioned 2016-01-01 through 2020-12-31)
EegGesetz::Eeg2021    — EEG 2021 plants (commissioned 2021-01-01 through 2022-12-31)
EegGesetz::Eeg2023    — EEG 2023 plants (commissioned from 2023-01-01)

Adding a future EEG variant requires only one new enum variant — the Rust compiler enforces exhaustive handling in all match sites across the codebase.

§51 is deliberately not one of these rules. EegGesetz exposes no §51 threshold and no kW exemption, because §51 is not a function of the law year: the Solarspitzengesetz took effect on 25 February 2025, inside the EEG 2023 range, so two "EEG 2023" plants can be governed by different §51 rules. NegativpreisRegime::fuer_inbetriebnahme is the single source — see §51 EEG — Negativpreisregel.

Bestandsschutz

The applicable settlement rules are determined according to the transition provisions of §100 EEG. Many rule aspects remain as originally commissioned; others (e.g. new sanctions, technical requirements, Solarpaket I changes) may apply regardless of the original commissioning date. Confirm specific plant scenarios against the applicable §100 provisions before relying on this simplification.

The §51 thresholds are set out in §51 EEG — Negativpreisregel and are keyed on the commissioning date, not on this column. Other rules may differ independently.

Sources: §100 Abs. 1 Satz 4 EEG 2017, §100 EEG 2021 Abs. 2 Nr. 13, §100 EEG 2023 Abs. 1.

Store eeg_gesetz as one of the canonical years (0, 2000, 2004, 2009, 2012, 2017, 2021, 2023). The from_db_year() function accepts intermediate years defensively (e.g. 2018 → EEG 2017, 2022 → EEG 2021).

§100 Transition Rules (TariffSource::Transitional)

For old plants with a specific §100 transition provision, supply tariff_source = Transitional(rule). eeg-billing then derives both the effective EegGesetz (for §52) and the §51 NegativpreisRegime from the rule rather than from the plant record — preventing a silent miscalculation when eeg_gesetz or the commissioning date is set incorrectly in the DB.

graph LR
    TR["TariffSource::Transitional(rule)"]
    TR -->|"Pre2016Bestandsschutz"| E12["§51 never applies<br/>(§100 Abs. 1 Satz 4 EEG 2017)"]
    TR -->|"Eeg2017Negativpreis6h<br/>BiomassOldFuelClassContinuation<br/>SmallBiomassBelow150kw"| E17["EEG 2017 regime<br/>≥ 6 h · 3 MW/500 kW"]
    TR -->|"OldPlantBeforeEeg2023"| E21["EEG 2021 regime<br/>≥ 4 h · 500 kW"]
    TR -->|"other rules"| EC["the plant's own date<br/>and eeg_gesetz"]

Paragraph100Rule	Effective regime	Source
Pre2016Bestandsschutz	§51 never applies	§100 Abs. 1 Satz 4 EEG 2017
Eeg2017Negativpreis6h	≥ 6 h, 3 MW/500 kW	§100 Abs. 2 Nr. 13 EEG 2021
BiomassOldFuelClassContinuation	EEG 2017 — old §42–44 fuel rules	§100 Abs. 6 EEG 2023
SmallBiomassBelow150kw	EEG 2017 — small biomass FiT	§100 Abs. 11 EEG 2023
OldPlantBeforeEeg2023	≥ 4 h, 500 kW (all types)	§100 Abs. 1 EEG 2023
all other rules	the plant's own commissioning date	—

Enforced by SettleInput::effective_eeg_gesetz() and SettleInput::negativpreis_regime() in the formula dispatcher.

§53 EEG — Vergütungsabzug

All EEG versions (2017, 2021, 2023) deduct a flat amount from the gross anzulegender Wert (AW) before paying Einspeisevergütung:

Technology	§53 deduction	Formula for DB storage
Solar PV, Wind	−0.4 ct/kWh	verguetungssatz_ct = AW − 0.4
Biomasse, Wasserkraft, Gas variants	−0.2 ct/kWh	verguetungssatz_ct = AW − 0.2

Always store the net rate in verguetungssatz_ct. Use the eeg_billing::rates::sect53_deduction(ErzeugungsArt) helper to compute it from the gross AW. §53 does not apply to Direktvermarktung, PostEegSpot, or KWKG plants.

Where the gross AW comes from

eeg_verguetungssaetze is generated from the Startwerte as enacted, stepped down by each statute's own Absenkung and stored net of the § 53 Abs. 1 deduction — the rate actually paid. These are the Startwerte the generator reads:

Erzeugungsart	§ EEG 2023	Shape
Wasserkraft	§ 40 Abs. 1	seven tiers, 12,03 → 3,37 ct
Deponie-, Klär-, Grubengas	§ 41 Abs. 1 / 2 / 3	one ladder each
Biomasse	§ 42 Satz 1	12,67 ct ≤ 150 kW; above that, tender
Bioabfall- / Güllevergärung	§ 43 / § 44	separate, higher claims
Geothermie	§ 45 Abs. 1	flat 25,20 ct
Solar	§ 48	in the version § 101 Abs. 1 Satz 2 keeps in force

There is deliberately no wind-onshore row: § 22 Abs. 2 makes the claim conditional on a BNetzA Zuschlag and § 36h derives the value from it, so an awarded value is imported per plant rather than seeded.

The same values live in eeg_billing::rates, asserted tier by tier by that crate's statutory_rate_tests. eeg_billing::seed::verguetungssatz_rows() projects them into the seed rows, and tests/verguetungssaetze_seed_guard.rs parses the migration and compares it row for row — a hand-edited seed row is a rate no statute contains.

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Generator Types (erzeugungsart)

Value	Technology	Legal basis
SOLAR_AUFDACH	Solar on a Gebäude or Lärmschutzwand (zweites Segment, §3 Nr. 41b)	§48 Abs. 2 / Abs. 2a EEG 2023
SOLAR_FREIFLAECHE	Freiflächenanlage (erstes Segment, §3 Nr. 41a)	§48 Abs. 1 / Abs. 1a EEG 2023
SOLAR_AGRIPV	Agri-PV — a besondere Solaranlage	§48 Abs. 1 S. 1 Nr. 5 lit. a + Abs. 1b EEG 2023
SOLAR_MIETERSTROM	Building community solar	§21 Abs. 3 + §48a EEG 2023
SOLAR_STECKER	Steckersolargerät, ≤2 kW and ≤800 VA inverter	§8 Abs. 5a EEG 2023
WIND_ONSHORE	Wind onshore	§46 (AW) · §36 (Gebote) EEG 2023
WIND_OFFSHORE	Wind offshore	Windenergie-auf-See-Gesetz (§22 Abs. 1 refers to it)
BIOMASSE / BIOMASSE_HOLZ	Solid biomass	§42 EEG 2023
BIOGAS / BIOMETHAN	Fermentation / upgraded gas	§42 (Biomethan excluded by Satz 2) · §43 · §44 EEG 2023
KLAERGAS / GRUBENGAS / DEPONIEGAS	Sewage / mine / landfill gas	§41 Abs. 2 / Abs. 3 / Abs. 1 EEG 2023
WASSERKRAFT / GEZEITEN	Hydro, tidal (§3 Nr. 21 lit. a makes tidal Wasserkraft)	§40 EEG 2023
GEOTHERMIE	Geothermal	§45 EEG 2023
KWKG	Combined heat & power	§7 KWKG 2023

There is deliberately no generic SOLAR: the §48 rate depends on the Bauform, so a plant recorded as "solar, unspecified" cannot be priced. Every plant also carries a verguetungsform (UEBERSCHUSS · VOLLEINSPEISUNG · KWK_ZUSCHLAG), because Überschuss- and Volleinspeisung rates for the same band and date differ by the §48 Abs. 2a bonus — 8,11 vs. 12,87 ct/kWh net for a ≤ 10 kWp roof plant commissioned in the 1 February 2024 § 49 window.

ErzeugungsArt also drives the §51 wind carve-out: under EEG 2017 wind turbines get the 3 MW exemption (§51 Abs. 3 Nr. 1), while solar and biomasse plants get 500 kW (Nr. 2). EEG 2021 dropped the distinction.

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Settlement Models

einsd stores one token per settlement model in eeg_anlagen.settlement_model, and the same token on every settlement_receipts row. The schema's CHECK list and einsd::models::ALL are asserted equal by tests/schema_code_guard.rs, so a model cannot be half-added.

There is exactly one token per model — no German/English aliases — so a gate cannot apply to one spelling and miss the other.

settlement_model	Regulation	Formula	CloudEvent
VERGUETUNG	§21 Abs. 1 EEG 2023	kwh × verguetungssatz_ct / 100	de.eeg.verguetung.berechnet
AUSFALLVERGUETUNG	§21 Abs. 1 Satz 1 Nr. 3 EEG 2023	same, at the statutory reduced rate	de.eeg.verguetung.berechnet
MIETERSTROM	§21 Abs. 3 EEG 2023	kwh × (verguetung + mieter_zuschlag) / 100	de.eeg.verguetung.berechnet
GGV	§42b EnWG	§21 rate on the grid feed-in at the GGV MaLo	de.eeg.verguetung.berechnet
DIREKTVERMARKTUNG	§20 EEG 2023	Anlage 1 gleitende Marktprämie, see below	de.eeg.marktpraemie.berechnet
AUSSCHREIBUNG	§22 EEG 2023	same formula, AW from the BNetzA tender	de.eeg.marktpraemie.berechnet
SONSTIGE_DIREKTVERMARKTUNG	§21a EEG 2023	EUR 0 EEG payment (revenue on the open market)	(none)
POST_EEG_SPOT	after the Förderdauer	kwh × Marktwert_ct / 100 (configurable floor)	de.eeg.verguetung.berechnet
EIGENVERBRAUCH	no grid feed-in	EUR 0	(none)
KWKG_ZUSCHLAG	§7 KWKG 2023	eligible_kwh × rate / 100 (hour-limit cap)	de.eeg.verguetung.berechnet
FLEXIBILITAET	§50b EEG 2023	kwh × (verguetung + flex_praemie) / 100	de.eeg.verguetung.berechnet
FLEXIBILITAET_ZUSCHLAG	§50a EEG 2023	kw × rate_eur_per_kw / 12 (capacity payment)	de.eeg.verguetung.berechnet

Ausschreibung is not a separate formula. It is the Marktprämie with TariffSource::Auction — the same calculation on an auction-determined anzulegender Wert. Award validity, reductions and revocation are the caller's responsibility; the library receives the already-resolved AW.

Anlage 1 EEG 2023 — die gleitende Marktprämie

Anlage 1 defines the Marktprämie as the anzulegender Wert minus the Marktwert, floored at zero:

Marktprämie = max(0, AW − MW) × kwh / 100

Which Marktwert applies is the plant's vintage, not the operator's choice. Anlage 1 Nr. 2 sends plants commissioned or bezuschlagt before 01.01.2023 to the energieträger­spezifische Monatsmarktwert of Nr. 3 and everything newer to the Jahresmarktwert of Nr. 4; Satz 3 then moves a Satz-1 plant onto the Jahresmarktwert as well once it claims under the § 19 Abs. 3b/3c Abgrenzungs- oder Pauschaloption (speicher_option on the plant).

marktwert_preise holds both series, distinguished by art, and the settlement asks for the one the plant is entitled to. The Zuschlag date matters on its own: a plant commissioned in 2024 on a 2022 award stays on the Monatsmarktwert, which a bare Inbetriebnahme test gets wrong.

Within the series the lookup goes exact technology → DEFAULT row → the generic EPEX monthly average → price_missing. It never falls through to the other series: substituting one for the other misprices every kWh, and price_missing is not a settled status, so the monthly worker simply retries once the figure lands.

A Jahresmarktwert has no month and its binding figure exists only once the year is over — the ÜNB publish a running estimate before that. A row may therefore be vorlaeufig, the receipt records that it was, and GET /api/v1/marktwert/{year}/nachbewertung lists every month that has to be recomputed when the final figure is published. The recomputation is POST /api/v1/anlagen/{tr_id}/settlements/{year}/{month}/correction, one plant at a time. It writes the correction beside the original, which stays live and unchanged — a § 147 AO Buchungsbeleg is amended, not overwritten.

PUT /api/v1/marktwert/2026/monat/SOLAR_FREIFLAECHE
{ "billing_month": 6, "avg_ct_kwh": "3.1400", "source": "netztransparenz.de" }

PUT /api/v1/marktwert/2026/jahr/SOLAR_FREIFLAECHE
{ "avg_ct_kwh": "4.8100", "vorlaeufig": true, "source": "netztransparenz.de" }

GET /api/v1/marktwert/2026/nachbewertung

There is no additive Managementprämie. Marketing costs have been folded into the anzulegender Wert since EEG 2014 — the §53 Vergütungsabzug (0.4 ct/kWh solar and wind, 0.2 ct/kWh biomass and gas) is that same cost appearing on the Einspeisevergütung route instead. Adding a premium on top would pay it twice.

When the Marktwert exceeds the AW the payment is zero: the plant earns from the market, and there is no guaranteed floor to fall back on.

KWKG rates. § 7 Abs. 1 Satz 1 prices the KWK-Zuschlag per Leistungsanteil, not by plant size: a plant's rate is the capacity-weighted blend of the bands its KWK-Leistung spans, which eeg_billing::kwkg::zuschlag_ct_kwh computes and zuschlag_leistungsanteile itemises.

Leistungsanteil	Rate	Nummer
≤ 50 kW	8,0 ct/kWh	Nr. 1
> 50 – 100 kW	6,0 ct/kWh	Nr. 2
> 100 – 250 kW	5,0 ct/kWh	Nr. 3
> 250 kW – 2 MW	4,4 ct/kWh	Nr. 4
> 2 MW	3,4 ct/kWh (neu / modernisiert) · 3,1 ct/kWh (nachgerüstet)	Nr. 5 lit. a–c

So a 2 MW new plant is (50×8 + 50×6 + 150×5 + 1750×4,4) / 2000 = 4,575 ct/kWh, not a single band's rate. Three qualifiers move it further:

• § 7 Abs. 1 Satz 2 adds 0,5 ct on Nr. 5 lit. a — but only for plants in Dauerbetrieb from 01.01.2023 (§ 35 Abs. 18) and only once the BMWK has published its Feststellung in the Bundesanzeiger, which is what kwk_bmwk_feststellung records.
• § 7 Abs. 2 has its own, lower ladders where the KWK-Strom is not fed into a Netz der allgemeinen Versorgung: kwk_verwendung names which (NETZ_DER_ALLGEMEINEN_VERSORGUNG, NICHT_EINGESPEIST_BIS100KW, NICHT_EINGESPEIST_KUNDENANLAGE, NICHT_EINGESPEIST_STROMKOSTENINTENSIV, NICHT_EINGESPEIST_BRANCHE_ANLAGE2).
• § 7 Abs. 3a replaces the ladder outright with a flat 16 ct (eingespeist) or 8 ct (nicht eingespeist) for a new plant up to 50 kW.

A KWKG plant has no Förderdauer in years. § 8 measures it in Vollbenutzungsstunden:

Anlagenart	Condition	Vollbenutzungsstunden
neu (Abs. 1)	—	30 000
modernisiert (Abs. 2 Nr. 1)	≥ 10 % Kostenanteil, 2 Jahre Karenz, Dampfsammelschiene > 50 MW	6 000
modernisiert (Abs. 2 Nr. 2)	≥ 25 %, 5 Jahre Karenz	15 000
modernisiert (Abs. 2 Nr. 3)	≥ 50 %, 10 Jahre Karenz	30 000
nachgerüstet (Abs. 3 Nr. 1)	≥ 10 % und < 25 %	10 000
nachgerüstet (Abs. 3 Nr. 2)	≥ 25 % und < 50 %	15 000
nachgerüstet (Abs. 3 Nr. 3)	≥ 50 %	30 000

A Modernisierung that meets no Nummer buys no Förderdauer at all, so foerderdauer_vollbenutzungsstunden answers None rather than a default.

§ 8 Abs. 4 caps each calendar year separately, and the cap falls over time: 5 000 h in 2021/22, 4 000 h in 2023/24, 3 500 h in 2025, 3 300 h in 2026, then 3 100 · 2 900 · 2 700 and 2 500 h from 2030. Exhausting the year's cap is jahreskontingent_erschoepft, not the end of the Förderung — see Monthly settlement state.

Settlement positions: Each calculation returns a positions array for full auditability. eeg-billing guarantees Σ(positions[*].eur) = settlement_eur.

Precision: rust_decimal::Decimal — never f64. See Quantities and money on the wire for the rounding rule every mako service shares.

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Plant Lifecycle

stateDiagram-v2
    [*] --> aktiv : POST /anlagen
    aktiv --> aktiv : POST /repowering<br/>(fresh Inbetriebnahme, keeps settling)
    aktiv --> foerderung_beendet : KWKG 30 000-h lifetime cap reached (§ 8 Abs. 1–3)
    aktiv --> abgemeldet : DELETE /anlagen · §24 Zusammenlegung

A plant is aktiv from registration. A missing MaStR entry does not hold it in a separate state — under §52 EEG 2023 the Vergütung keeps flowing and a Pflichtzahlung accrues alongside it, which settlement_state records rather than status. Repowering leaves the plant aktiv; it is recorded by ist_repowering + repowering_datum.

Monthly settlement state

In addition to the plant status column, each plant has a settlement_state that reflects its current billing lifecycle:

stateDiagram-v2
    [*] --> active : all compliance OK
    active --> reduced : §52 EEG 2023 penalty active<br/>(Vergütung still flows)
    reduced --> active : violation resolved
    active --> suspended : §52 EEG ≤2021 VerguetungAufNull<br/>(MaStR missing, old EEG)
    suspended --> active : MaStR / compliance restored
    active --> post_eeg : billing_date > foerderendedatum<br/>(EEG only — a KWKG plant has none)
    active --> ended : plant decommissioned
    active --> interrupted : no meter data / no EPEX price
    interrupted --> active : data arrives

settlement_state	Meaning
active	Full Vergütung flows normally.
reduced	§52 EEG 2023 Pflichtzahlung active; Vergütung unchanged.
suspended	§52 EEG ≤2021 VerguetungAufNull; no payment.
interrupted	Temporary: no meter data or EPEX price missing.
post_eeg	Förderdauer expired; EPEX spot basis.
ended	Plant decommissioned.

The settlement_state_transitions audit table logs every change with the reason (MastrRegistered, Sect52ViolationDetected, FoerderungExpired, …).

Status (plant)	Meaning
aktiv	Registered and settling.
foerderung_beendet	The § 8 KWKG lifetime Vollbenutzungsstunden are used up, or an Ausschreibungs-Zuschlag lapsed (§§ 36e / 37e / 39e EEG 2023).
abgemeldet	Decommissioned, or merged into a parent under §24.

These are the only three values the service writes. A plant past its EEG Förderende stays aktiv — its receipts carry status = foerderung_beendet for the months concerned, and settlement_state = post_eeg records the lifecycle position.

A KWK plant whose annual § 8 Abs. 4 contingent runs out mid-year is not retired: the receipt for those months carries status = jahreskontingent_erschoepft and the plant stays aktiv, because the Förderung resumes on 1 January. Only the lifetime cap moves the plant to foerderung_beendet, and a correction that removes kWh moves it back to aktiv.

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Inbetriebnahmeprozess

1. Physical commissioning by operator.
2. NB registers in einsd via POST /api/v1/anlagen (mastr_registriert: false if pending).
3. Operator registers plant at marktstammdatenregister.de.
4. NB confirms via POST /api/v1/anlagen/{tr_id}/mastr-registrierung → plant → aktiv.
5. Monthly settlement auto-runs. Vergütung dispatched via CloudEvent.

Registering a plant

POST /api/v1/anlagen
Content-Type: application/json

{
  "tr_id":              "DE0123456789012345678901234567890",
  "malo_id":            "51238696012",
  "eeg_gesetz":         2023,
  "inbetriebnahme":     "2024-06-01",
  "leistung_kwp":       "9.8",
  "erzeugungsart":      "SOLAR_AUFDACH",
  "verguetungssatz_ct": "8.11",
  "settlement_model":   "VERGUETUNG",
  "mastr_registriert":  true,
  "mastr_nummer":       "SEE900000012345",
  "einspeiser_id":      "EB-4711"
}

einspeiser_id names the plant's Anlagenbetreiber (see below) and is mandatory: § 7 Abs. 1 EEG 2023 puts the payment on the Netzbetreiber, so a plant nobody can be paid for is not one this service can act on. Register the operator first.

verguetungssatz_ct = net rate (gross AW − §53 deduction). For a ≤ 10 kWp roof plant commissioned in the 1 February 2024 §49 window: 8.60 ct base × 0.99 = 8.51 ct gross AW, − 0.4 ct = 8.11 ct net. Use POST /api/v1/verguetungssatz-lookup to get the gross AW, then subtract with eeg_billing::rates::sect53_deduction().

foerderendedatum is computed automatically for an EEG plant:

• Statutory plants (no BNetzA tender): December 31 of year+20 (§25 Abs. 1 Satz 2 EEG) — 2024-06-01 → 2044-12-31
• Ausschreibungsanlagen (ausschreibungs_zuschlag_id set): exact 20-year anniversary — 2024-06-01 → 2044-06-01

A KWKG plant has no Förderende at all, and foerderendedatum is NULL for one — the column is nullable for exactly this case. § 8 KWKG caps the Zuschlag „für bis zu 30 000 Vollbenutzungsstunden" (Abs. 1–3) — a generation counter, not a calendar date — with a separate, falling per-Kalenderjahr cap (Abs. 4; 3 300 h in 2026). The plant ends on kwk_foerderdauer_h, which POST /api/v1/anlagen takes directly or derives from kwk_anlagenart (+ kwk_kostenanteil for a Modernisierung or Nachrüstung); nothing derives a date from it, because none exists to derive. Every read of foerderendedatum therefore has to handle NULL.

Confirming MaStR registration

POST /api/v1/anlagen/{tr_id}/mastr-registrierung
Content-Type: application/json

{ "mastr_nummer": "SEE900000012345", "mastr_datum": "2024-06-15" }

Clears the §52 Abs. 1 Nr. 11 violation clock and emits de.eeg.anlage.mastr-registriert so the ERP can release any withheld payment. The plant status is untouched — it was already aktiv.

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Einspeiser (Anlagenbetreiber)

The party behind the plants is a record of its own, einspeiser, keyed by an operator-assigned einspeiser_id (a customer number, a MaStR Marktakteur-ID, or a UUID the ERP mints — einsd does not invent identities for parties it did not register). A plant points at one with eeg_anlagen.einspeiser_id.

It is deliberately not a Vertrag. § 7 Abs. 1 EEG 2023 („Gesetzliches Schuldverhältnis") forbids the Netzbetreiber from making its EEG obligations conditional on a contract, so what the settlement needs is a party record.

What it carries is the set of facts that belong to the person rather than to any one installation:

Field	Why it is per operator
ust_status	The § 19 UStG Kleinunternehmer election is made by the person, not per installation. KLEINUNTERNEHMER → 0 %, EN 16931 category E; REGELBESTEUERUNG → 19 %, category S
bank_iban / bank_bic / zahlungsempfaenger	One payout account; forwarded in the settlement CloudEvent so accountingd builds the pain.001 without a second lookup
mastr_akteur_id	The MaStR Marktakteursnummer (SEE…/ABR…), where the operator has one

ust_status decides the VAT on every feed-in Gutschrift the operator is issued. § 12 Abs. 3 UStG — the 0 % rate on PV hardware supply — is not a feed-in category and never appears here.

PUT /api/v1/einspeiser/EB-4711
Content-Type: application/json

{
  "name":               "Max Mustermann",
  "mastr_akteur_id":    "ABR900000012345",
  "ust_status":         "KLEINUNTERNEHMER",
  "bank_iban":          "DE89370400440532013000",
  "bank_bic":           "COBADEFFXXX",
  "zahlungsempfaenger": "Max Mustermann"
}

One call switches the VAT on every one of the operator's plants. An ust_status this build does not know aborts the settlement rather than falling back to a default — a § 14 UStG document may not carry a VAT rate the Netzbetreiber inferred.

---

Registration is validated, not merely stored

POST /api/v1/anlagen refuses a plant the settlement could not honestly act on, and the message names the field. The rules are in validate::check, and the ones that matter are not stylistic:

Rejected	Why
DIREKTVERMARKTUNG without a positive direktverm_aw_ct	the Marktprämie is max(0, AW − Marktwert), so every month would settle to EUR 0 with status calculated and emit a payout event for it
AUSSCHREIBUNG without an AW or without ausschreibungs_zuschlag_id	same arithmetic; and an awarded value with no award behind it cannot be audited
leistung_kwp ≤ 0	it drives the §9 band, the §52 charge (10 €/kW — a negative capacity would credit the operator), the §44b quota and the §51 size test
MIETERSTROM without mieter_zuschlag_ct	the plant would settle as a plain Einspeisevergütung
KWKG_ZUSCHLAG with neither kwk_foerderdauer_h nor kwk_anlagenart	§8 KWKG bounds the Zuschlag in Vollbenutzungsstunden; with neither the hours nor the Anlagenart to derive them from, it never ends. A MODERNISIERT or NACHGERUESTET plant additionally needs kwk_kostenanteil — §8 Abs. 2/3 key the hours on it
technology and statute disagreeing	a KWK plant with eeg_gesetz ≠ 0, an EEG plant with 0, a solar plant on the KWKG model, or a verguetungsform that belongs to the other statute

A tender plant may carry its anzulegender Wert in either column. zuschlagswert_ct — the field named after the award — takes precedence at settlement.

The engine holds the same line independently: a Marktprämie with no AW is PriceMissing, not a zero settlement. Zero is only ever a derived AW (§51, §51b, §54 Abs. 4), and each of those sets it after the check.

---

§9 / §52 EEG — Steuerbarkeit und Pflichtzahlungen

§52 Abs. 1 lists thirteen Pflichtverstöße — it counts to twelve but inserts a Nr. 9a between 9 and 10. Each charges the operator 10 €/kW per calendar month (Abs. 2), some drop to 2 € (Abs. 3), four run past the breach itself (Abs. 4), the total is capped at 10 €/kW per month (Abs. 5) and the claim may be netted against the Vergütung (Abs. 6).

They reach a settlement from two sources, merged in one place (sect52::derive_pflichtverstoesse):

§52 Abs. 1	Violation	Source
Nr. 1	§9 Steuerbarkeit not satisfied	derived — routes carried × capacity × Veräußerungsform
Nr. 5	Ausfallvergütung past its Höchstdauer	derived — from the settlement receipts
Nr. 9	§21c switch not notified	derived — veraeusserungsform_notification_sent_at
Nr. 11	MaStR registration missing	derived — mastr_registriert, with mastr_violation_start as its clock
Nr. 2, 3, 4, 6, 7, 8, 9a, 10, 12	Speicher, iMSys, §10b, §21 Abs. 2, §21b Abs. 2/3, §37 Abs. 1a / §48 Abs. 6, Volleinspeisung, §80	recorded in eeg_pflichtverstoesse

The nine recorded ones are not derivable in principle, not merely unimplemented: §10b Abs. 5 leaves the Nachweis that a Direktvermarkter can actually curtail the plant to the Netzbetreiber and the Direktvermarktungsunternehmen, §9 Abs. 5's Speicheranforderung is a site visit, and Doppelvermarktung is a finding. The register is where such a finding is filed.

The register

POST /api/v1/anlagen/{tr_id}/pflichtverstoesse
{ "typ": "I_MSS_ANFORDERUNG_NICHT_ERFUELLT", "beginn": "2026-01-01",
  "technischer_defekt": false, "notiz": "Vor-Ort-Prüfung 12.01.2026" }

PUT  /api/v1/anlagen/{tr_id}/pflichtverstoesse/I_MSS_ANFORDERUNG_NICHT_ERFUELLT/behoben
{ "behoben_am": "2026-06-20" }

GET  /api/v1/anlagen/{tr_id}/pflichtverstoesse

409 when one of that Nummer is already open — a breach recurs, so the history is kept and only the open entry is unique. A typ outside the vocabulary answers 400 with the vocabulary, and tests/schema_code_guard.rs holds the SQL CHECK against SanktionsTyp::ALL, so a fourteenth breach cannot land in the code and be rejected by the database.

It also supplies what a derivation cannot state on its own, and each of the three moves money:

Field	Effect
beginn	§52 Abs. 2 charges „pro Kalendermonat, in dem ganz oder zeitweise ein Pflichtverstoß … vorliegt". Without it the charge is one month, however long the breach has run
behoben_am	§52 Abs. 3 Satz 1 Nr. 1 drops the rate to 2 €/kW „zurück bis zum Beginn", for Nr. 1, 3, 4 and 11 only
technischer_defekt	§52 Abs. 3 Satz 2 waives the defect month and the following one for Nr. 1/3/4/8, for breaches after 31.12.2023. The Darlegungs- und Beweislast is the operator's, which is why it is stated rather than inferred

The Abs. 3 cure is a fifth of the charge, and it reaches only those four Nummern: Nr. 9a and Nr. 10 are at 2 € from the start (Satz 1 Nr. 2), and everything else stays at 10 € however thoroughly it was cured.

Because Abs. 3's reduction reaches back to the beginning, a cure makes every month already settled at 10 € an overcharge. Correct them with POST /api/v1/anlagen/{tr_id}/settlements/{year}/{month}/correction; the response to the cure says so.

A record never creates a breach einsd derives. For Nr. 1, 5, 9 and 11 the plant record decides whether there is a breach and the record only refines it, so closing an entry cannot silence a violation the plant still shows. Conversely a §10b record filed against a plant on the Einspeisevergütung charges nothing: §10b Abs. 1 binds the operator of a plant over 25 kW that direct-markets.

§52 Abs. 4 — four breaches outlive themselves

SanktionsTyp::abs4_monate applies them, so no caller has to remember:

§52 Abs. 4	Nummer	Effect
Nr. 1	Nr. 7 (§21b Abs. 2 Satz 1 Hs. 2)	+ the following three calendar months
Nr. 2	Nr. 9 (§21c)	+ the following calendar month
Nr. 3	Nr. 10 (Volleinspeisung)	all calendar months of the year — a replacement, not an addition
Nr. 4	Nr. 12 (§80 Doppelvermarktung)	+ the following six calendar months

Nr. 5 is deliberately absent: Abs. 4 does not name it, and adding three months there would charge a plant on the Ausfallvergütung a quarter it does not owe.

§9 is staged by capacity and gated on the Veräußerungsform

§9 Abs. 2 Satz 1 has three Nummern, and the middle one carries two duties joined by „und" — the „oder" that follows lit. b separates Nr. 2 from Nr. 3. Which of them applies also depends on how the plant is paid: lit. b and Nr. 3 bind only „Anlagen, die der Einspeisevergütung oder dem Mieterstromzuschlag nach §19 Absatz 1 Nummer 2 oder Nummer 3 zugeordnet sind", and Nr. 3 additionally every KWK-Anlage of that size.

Installed capacity	Ferngesteuerte Reduzierung	60 % Wirkleistungsbegrenzung	Basis
Steckersolargerät ≤ 2 kW und ≤ 800 VA	–	–	§9 Abs. 2 Satz 4
< 25 kW	–	nur geförderte Anlagen und KWK-Anlagen	§9 Abs. 2 Satz 1 Nr. 3
25 kW – < 100 kW	ja	nur geförderte Anlagen	§9 Abs. 2 Satz 1 Nr. 2 lit. a und lit. b
≥ 100 kW	ja	–	§9 Abs. 2 Satz 1 Nr. 1

The two routes are separate facts, so a plant records both:

{ "sect9_fernsteuerbarkeit": true, "sect9_begrenzung_60": true }

Anything the obligation names and the plant does not carry is a §52 Abs. 1 Nr. 1 breach at 10 €/kW/Kalendermonat. Carrying more than is owed never is — a directly-marketed plant that limits itself to 60 % anyway stays compliant. wechselrichterleistung_va is the second half of the Steckersolar carve-out; left unstated it keeps the carve-out shut.

---

§51 EEG — Negativpreisregel

During negative EPEX Spot periods the anzulegender Wert falls to zero. Which version of §51 applies is a function of the plant's Inbetriebnahmedatum, not of its EEG law year.

The Solarspitzengesetz (Gesetz zur Änderung des EnWG, in force 25 February 2025) rewrote §51 mid-year. Two plants that are both "EEG 2023" plants are therefore governed by entirely different rules depending on the day they were commissioned — a 200 kWp plant from June 2024 is exempt, the same plant from June 2025 is not. eeg-billing models this with NegativpreisRegime::fuer_inbetriebnahme, keyed on the exact date.

Inbetriebnahme	§51 trigger	Exemption	§51a extension
≤ 2015-12-31	never applies (§100 Abs. 1 Satz 4 EEG 2017)	—	—
2016-01-01 – 2020-12-31	≥ 6 consecutive hours	Wind < 3 MW · sonstige < 500 kW	none
2021-01-01 – 2022-12-31	≥ 4 consecutive hours	< 500 kW (wind carve-out removed)	ausschreibungspflichtige only
2023-01-01 – 2025-02-24	staged 4-3-2-1 h (4 h for IBN 2023, 3 h from IBN 2024)	< 400 kW	ausschreibungspflichtige only
≥ 2025-02-25	from the first negative quarter-hour	< 100 kW until iMSys · < 2 kW until the §85 Abs. 2 Nr. 12 Festlegung	all plants

Pilotwindenergieanlagen (§3 Nr. 37 EEG 2023) are carved out under every version at any size — register them with ist_pilotwindanlage: true.

§100 — the Bestandsanlagen opt-in

A plant on an older vintage may declare in Textform to the Netzbetreiber that §§ 51 and 51a shall apply to it. The declaration runs at the earliest from the end of the calendar year in which the plant is fitted with an iMSys, and from then the plant forgoes payment during negative prices and is paid 0,6 ct/kWh more on its anzulegender Wert for everything else.

Record the declaration date on the plant; einsd derives the effective date from it and imesys_rollout_datum, and picks the regime per billing period:

{ "sect51_optin_erklaert_am": "2026-03-01", "imesys_rollout_datum": "2026-09-01" }

A declaration on a plant without an iMSys is on file and simply does not run yet.

graph LR
    IBN["Inbetriebnahmedatum"]
    IBN -->|"≤ 2015-12-31"| A["§51 does not apply<br/>(§100 Abs. 1 Satz 4 EEG 2017)"]
    IBN -->|"2016–2020"| B["≥ 6 h consecutive<br/>Wind < 3 MW · other < 500 kW"]
    IBN -->|"2021–2022"| C["≥ 4 h consecutive<br/>< 500 kW exempt"]
    IBN -->|"2023 – 24.02.2025"| D["staged 4-3-2-1 h<br/>< 400 kW exempt"]
    IBN -->|"≥ 25.02.2025"| E["first negative ¼h<br/>< 100 kW until iMSys<br/>< 2 kW pending BNetzA"]

The reduction is driven by two inputs on the settle request — the feed-in that fell in qualifying negative-price intervals (kwh_during_negative_epex, §51) and the count of those quarter-hours (negative_price_quarter_hours, §51a):

POST /api/v1/anlagen/{tr_id}/settle/2026/7
Content-Type: application/json

{ "einspeisemenge_kwh": "1000", "kwh_during_negative_epex": "80", "negative_price_quarter_hours": 16 }

Result: effective_kwh = 920; settlement_eur = 920 × rate / 100.

Or omit both and let einsd derive them. Load the EPEX day-ahead spot prices once, and every settle (single, batch and the monthly auto-settle) that does not carry explicit values fetches the plant's ¼h feed-in from edmd (GET /api/v1/energy/{malo_id}?direction=EINSPEISUNG), overlays it against the stored prices, and applies the plant's regime — including its run-length threshold — in eeg-billing::negativpreis:

PUT /api/v1/epex-spot
Content-Type: application/json

{ "source": "epex-day-ahead",
  "prices": [ { "delivery_start": "2026-07-01T12:00:00Z", "resolution_min": 15, "price_ct_kwh": "-1.5" }, … ] }

The billing month is taken in Europe/Berlin, not UTC: both the day-ahead curve and edmd's ¼h series are published for the German market time, so a UTC window shifted the month by an hour (two at DST) and matched the first hour against the previous month's prices.

A § 40a Abs. 2 EnWG gate guards the auto-derivation: when edmd reports the month's feed-in coverage below 95 % or any non-billable interval, einsd skips the automatic reduction and logs it — below that threshold the figures would be an undisclosed estimate, which Satz 3 does not permit (deriving on incomplete data would find too few negative kWh and overpay) — supply kwh_during_negative_epex manually or backfill substitute values in edmd instead. A month that genuinely had no qualifying quarter-hour derives as zero, which is a different answer from "nothing was known" and is recorded as such. The engine then applies the size / iMSys / Pilotwind exemptions on top of the derived kWh. Explicit request values always win. The edmd fetch authenticates with edmd_api_key, which must be registered in edmd's [[oidc.service_keys]] (see below).

Applies to: VERGUETUNG, AUSFALLVERGUETUNG, MIETERSTROM, GGV, DIREKTVERMARKTUNG, AUSSCHREIBUNG, FLEXIBILITAET. Not to: POST_EEG_SPOT (no AW left to reduce), KWKG_ZUSCHLAG (a different statute), EIGENVERBRAUCH, SONSTIGE_DIREKTVERMARKTUNG, FLEXIBILITAET_ZUSCHLAG (capacity-based).

§51a — Verlängerung des Vergütungszeitraums

For the quarter-hours where §51 reduced the AW to null, the Vergütungszeitraum is extended. The claim is not universal: before the Solarspitzengesetz it existed only for ausschreibungspflichtige Anlagen, so a statutory-AW plant commissioned in 2024 loses those quarter-hours outright. From 25 February 2025 it covers every plant §51 reduces.

einsd accrues the raw lost quarter-hours per plant (negative_price_qh_gesamt), and the rounding is applied once over the 20-year total when settling — never per month — so the extension never over-counts:

• Solar PV: the quarter-hours are multiplied by 0,5 into a Volllastviertelstunden contingent and drawn down against the §51a Abs. 2 monthly table (73 in December, 508 in June).
• All others: rounded up to whole calendar days (96 QH/day, Abs. 1 Satz 2).

The plant's stored foerderendedatum stays the statutory one; effektives_foerderende derives the extended end at settlement time, so a plant keeps being paid through the extension. §51a extends an EEG Förderdauer, so it applies only where there is a stored date to extend — a KWKG plant has none and is bounded by Vollbenutzungsstunden instead.

A correction settlement that carries no §51 figures leaves the period's accrual unchanged. The accrual row holds each period's absolute contribution, so writing a zero would silently hand back an extension the original settlement had earned.

§36h Abs. 2 — Wind Standortgüte re-evaluation

An onshore wind plant's anzulegender Wert is location-corrected by a Korrekturfaktor derived from its Gütefaktor (§36h Abs. 1, Anlage 2). Under §36h Abs. 2, that Gütefaktor is re-evaluated with effect from the start of the 6th, 11th and 16th operating year against the measured Standortertrag of the preceding five years. Record each one:

POST /api/v1/anlagen/{tr_id}/wind-reevaluation
Content-Type: application/json

{ "wirksam_ab_jahr": 6, "guetefaktor": "0.95" }

einsd stores the re-evaluations in wind_guetefaktor_reevaluations and, at settle time, build_settle_input selects the Korrekturfaktor whose effective year has been reached — so a plant automatically steps to the re-evaluated rate from year 6/11/16. The response flags reconciliation_required when the recomputed Gütefaktor deviates more than 2 percentage points (§36h Abs. 2 Satz 2): settle the reviewed five-year period's over-/under-payment as a §147 AO correction (repayment interest EURIBOR-12M + 1 pp, Satz 3).

§51b — Biogas Ausschreibung at slightly-positive prices

§51b EEG 2023 applies exclusively to biogas plants (fermentation only, not biomethane) whose Anzulegender Wert was set by BNetzA tender. The rule is triggered by a slightly-positive EPEX price, not a negative one:

When epex_avg_ct_kwh ≤ 2 ct/kWh, the AW reduces to zero for that period. No payment is made. §51/§51a do not apply to these plants (§51b Satz 2 EEG 2023).

graph LR
    EPEX["EPEX avg<br/>ct/kWh"]
    EPEX -->|"<= 2 ct/kWh"| ZERO["AW = 0<br/>Payment = EUR 0<br/>§51/§51a do NOT apply"]
    EPEX -->|"> 2 ct/kWh"| NORMAL["Normal MarketPremium formula<br/>Prämie = max(0, AW - Monatsmarktwert) x kwh"]

Register biogas Ausschreibungsanlagen with is_biogas_sect51b: true. The settlement formula automatically returns EUR 0 with position label §51b EEG 2023 for any period where the EPEX average is ≤ 2 ct/kWh.

§51b applies only from 18 September 2025. § 101 Abs. 2 Satz 1 puts it under a state-aid Genehmigungsvorbehalt and names no earlier version to fall back on, so eeg_billing::version::sect51b_anwendbar keys on the supply period, not on when the Gutschrift is written: a 2026 correction for August 2025 settles a supply §51b did not reach. A period whose start is unknown, and one that straddles the approval day, are both false — the latter has qualifying quarter-hours on both sides and one Marktwert for the whole period, so it has to be billed as two periods.

---

§21 Abs. 1 Satz 1 Nr. 3 — Ausfallvergütung

The fallback for a plant above 100 kW whose Direktvermarkter drops out. Two rules attach to it, and both are enforced:

• §53 Abs. 3: the anzulegender Wert is reduced by 20 %, rounded to two decimals. Register the plant's ordinary rate — the engine applies the cut.
• Höchstdauern: at most three consecutive calendar months and six calendar months per calendar year. Exceeding either is a §52 Abs. 1 Nr. 5 Pflichtverstoß at 10 €/kW/month, counted from the settlement receipts.

POST /api/v1/anlagen/{tr_id}/settle/2026/4

A plant in its fourth consecutive Ausfallvergütung month is still settled — the statute does not stop the payment — and the receipt carries the Pflichtzahlung alongside it.

§51 Abs. 3 — the reporting duty

An operator on the Ausfallvergütung must report, with the §71 Abs. 1 Nr. 1 data, the quantity it fed in while the Spotmarktpreis was continuously negative. Where nothing establishes that quantity, the month's claim falls by 5 % per calendar day on which such a period fell, wholly or partly — twenty such days extinguish it.

einsd counts the days from the EPEX spot store (in Europe/Berlin, so a run across midnight counts both days) and applies the cut only when the §51 feed-in figure could not be established at all. A figure derived from edmd counts as established: it comes from the Netzbetreiber's own metering, which is what the report would have supplied.

The two reductions compose in statutory order — §53 Abs. 3 cuts the anzulegender Wert, then §51 Abs. 3 cuts the resulting claim.

---

§49 EEG 2023 — Solar PV degression

§49 degression is semi-annual, not quarterly. Solar anzulegende Werte fall by a fixed 1 % every six months, on 1 February and 1 August, starting 01.02.2024. The steps compound on the unrounded value and each result is rounded kaufmännisch to the cent, which is what reproduces the BNetzA-published series exactly. The GW-dependent "atmender Deckel" of earlier EEG versions no longer exists.

A window bounds the Inbetriebnahmedatum, not the settled month: every §§ 40–49 Absenkung applies „für die nach diesem Zeitpunkt in Betrieb genommenen Anlagen", so a plant keeps its window's value for the whole Förderdauer.

The base ladder (§ 48 Abs. 2 / Abs. 2a), gross AW before any §49 step — i.e. the values for a plant commissioned 01.01.2023 – 31.01.2024:

Capacity	Überschusseinspeisung	Volleinspeisung
≤10 kWp	8.60 ct/kWh	13.40 ct/kWh
≤40 kWp	7.50 ct/kWh	11.30 ct/kWh
≤100 kWp	6.20 ct/kWh	11.30 ct/kWh
≤400 kWp	6.20 ct/kWh	9.40 ct/kWh
≤1 MWp	6.20 ct/kWh	8.10 ct/kWh

Volleinspeisung is the base plus the § 48 Abs. 2a uplift (+4,8 / +3,8 / +5,1 / +3,2 / +1,9 ct), and §49 names Abs. 2a expressly, so the uplift degresses in step rather than staying nominal.

These are not the Solarpaket-I figures, and that is deliberate. The consolidated text of § 48 Abs. 2 reads 8,51 / 7,43 / 7,64 ct, but § 101 Abs. 1 Satz 1 lists Abs. 2 among the provisions that may be applied only after EU state-aid approval, and Satz 2 directs that until then the version in force on 15 May 2024 — the 8,60 / 7,50 / 6,20 ladder — applies. That is also the series the Bundesnetzagentur publishes.

For any other commissioning date use the lookup_statutory_rate MCP tool or POST /api/v1/verguetungssatz-lookup, which resolve the §49 window.

---

§§20–22 EEG 2023 — Veräußerungsformen, Direktvermarktungspflicht, Ausschreibung

The Direktvermarktungspflicht is the shadow of §21 Abs. 1 Satz 1 Nr. 1

The EEG contains no section imposing a duty to market directly. What it contains is a ceiling: the Einspeisevergütung mit gesetzlich bestimmtem anzulegenden Wert exists only „für Strom aus Anlagen mit einer installierten Leistung von bis zu 100 Kilowatt". A larger plant that wants to be paid has to take the Marktprämie (§20), which §20 Satz 1 Nr. 1 pays only for months in which the Strom is direkt vermarktet.

So a plant over 100 kW left on VERGUETUNG is not penalised — it is unpaid. The settlement answers kein_anspruch with a EUR 0 position naming §21 Abs. 1 Satz 1 Nr. 1, and check_einspeiseverguetung_anspruch lists the portfolio. §52 Abs. 1 Nr. 4 is a different fact entirely: a breach of §10b, the Abruf- und Fernsteuerbarkeit a plant over 25 kW that direct-markets owes its Direktvermarktungsunternehmen. A plant on the Einspeisevergütung is not in a Direktvermarktung and cannot breach it.

Use AUSFALLVERGUETUNG for a plant whose Direktvermarkter dropped out — §21 Abs. 1 Satz 1 Nr. 3, capped at three consecutive and six calendar months per year, and reduced 20 % by §53 Abs. 3. It is open to a plant above 100 kW; that is what it exists for.

A plant commissioned before 2016-01-01 is governed by the EEG 2014 staging (500 kW from 01.08.2014, 100 kW from 01.01.2016), which mako's regulatory corpus does not carry. direktvermarktungspflicht answers None for it and the settlement pays it rather than refusing on an unsourced threshold; the MCP tool lists it under ungeklaert.

Ausschreibungspflicht (§22 Abs. 2–5)

The exemption is stated as „bis einschließlich", so the threshold value itself is still exempt.

Technology	Exempt up to and including	Source
Solar, erstes Segment — Freiflächenanlagen and solar on baulichen Anlagen that are neither Gebäude nor Lärmschutzwand (§3 Nr. 41a)	1 MW	§22 Abs. 3 Satz 2 Nr. 1
Solar, zweites Segment — on, at or in a Gebäude or a Lärmschutzwand (§3 Nr. 41b)	750 kW	§22 Abs. 3 Satz 2 Nr. 1a
Wind an Land	1 MW	§22 Abs. 2 Satz 2 Nr. 1
Biomasse	150 kW (except bestehende Anlagen nach §39g, which always need a Zuschlag)	§22 Abs. 4 Satz 2
Wasserkraft, Deponiegas, Klärgas, Grubengas, Geothermie	any size — their AW stays gesetzlich bestimmt by §§40–49 and no Ausschreibung exists for them at all	§22 Abs. 5 Satz 2
Wind offshore	nothing — the Zuschlag and the AW come from the Windenergie-auf-See-Gesetz	§22 Abs. 1

Two exemptions are deliberately not applied by eeg_billing::direktverm::requires_ausschreibung, because neither is a capacity test: Pilotwindenergieanlagen an Land (125 MW per year across the cohort, §22 Abs. 2 Satz 2 Nr. 2) and Anlagen von Bürgerenergiegesellschaften (Wind bis 18 MW, Solar bis 6 MW, §22b). The 6-MW figure belongs to that last row — it is not an Agri-PV rule; Agri-PV is a besondere Solaranlage of the erstes Segment and takes the 1-MW threshold.

Plants above the threshold must use tariff_source = Auction with the BNetzA-awarded AW. The direktvermarktung and capacity_blocks columns track this.

---

Multi-Meter Messkonzept

German EEG plants can have multiple measurement points. einsd stores none of that: the metering topology and computation — the Eigenverbrauch/Überschuss split and the §42b EnWG GGV tenant allocation — belong to the metering domain, owned by edmd and the external metering crate (AggregationRule with PvSelfConsumption, GgvConstantAllocation, GgvProportionalAllocation; compute_virtual_meter; MeasurementPoint). einsd settles on the already-aggregated Einspeisemenge edmd returns from GET /api/v1/energy/{malo_id}?direction=EINSPEISUNG — the same projected ¼h series the §51 overlay reads — so the settlement engine never re-derives the metering split.

It deliberately does not read GET /api/v1/billing-period/{malo_id}: its arbeitsmenge_kwh is the Bezug, projected onto the consumption registers, and an Erzeugungs-MaLo reports only 1-0:2.8.x. That projection is empty over it, so the field reads 0 kWh rather than being absent — a settlement on it pays nothing while a dry run counts the plant as "has data".

graph TB
    subgraph Simple["Simple (most common)"]
        BM["Bidirectional meter<br/>OBIS 1-0:2.8.0 (Einspeisung)<br/>OBIS 1-0:1.8.0 (Bezug)"]
    end
    subgraph VE["Volleinspeisung (2 meters)"]
        EM["Erzeugungsmessung<br/>(billing basis)"]
        BZ["Bezugsmessung"]
    end
    subgraph GGV["§42b EnWG GGV (multi-tenant)"]
        GEN["Generation meter"]
        T1["Tenant A meter"]
        T2["Tenant B meter"]
        GEN --> T1
        GEN --> T2
    end

For §42b Gemeinschaftliche Gebäudeversorgung, the tenant-vs-grid split (constant CCI+ZG6 or proportional Z74 allocation) is computed in edmd via metering::AggregationRule; einsd receives the resulting feed-in quantity and settles it.

---

§52 EEG — the full violation catalogue

The detection and the §9 bands are in §9 / §52 EEG — Steuerbarkeit und Pflichtzahlungen; this is the catalogue the engine prices against.

Old plants (EEG ≤2021 via §100 Übergangsregelung)

Old plants use the three-tier SanktionAlt model — the breach reduces the Vergütung itself, and there is no separate Pflichtzahlung to charge:

Tier	§52 EEG ≤2021	Vergütung effect
VerguetungAufNull	Abs. 1	→ EUR 0 (MaStR not registered, §10b, §27a)
VerguetungAufMarktwert	Abs. 2	→ EPEX Monatsmarktwert (§9 Fernsteuerbarkeit missing)
VerguetungReduziert20Prozent	Abs. 3	→ ×0.80, rounded to 2dp (MaStR late/partial)

New plants (EEG 2023, commissioned from 2023-01-01)

§52 Abs. 2: Pflichtzahlung from operator to NB — the Vergütung keeps flowing and the charge may be netted against it (Abs. 6).

SanktionsTyp	Nr.	Rate	Retroactively reducible?	Derived by einsd?
FernsteuerbarkeitFehlend	Nr. 1	€10/kW/month	Yes → €2 on fulfilment	yes
SpeicherAnforderungNichtErfuellt	Nr. 2	€10/kW/month	No	no
IMssAnforderungNichtErfuellt	Nr. 3	€10/kW/month	Yes → €2	no
Sect10bVorgabenVerletzt	Nr. 4	€10/kW/month	Yes → €2	no
AusfallverguetungHoechstdauerUeberschritten	Nr. 5	€10/kW/month	No	yes
EinspeiseverguetungUnzulaessigeNutzung	Nr. 6	€10/kW/month	No	no
VeraeusserungsformWechselUngueltig	Nr. 7	€10/kW/month	No	no
VeraeusserungsformNachweispflichtVerletzt	Nr. 8	€10/kW/month	No	no
ZuordnungsWechselNichtGemeldet	Nr. 9	€10/kW/month	No	yes
InbetriebnahmeVorgabeVerletzt	Nr. 9a	€2/kW always	N/A (Abs. 3 Nr. 2)	no
VolleinspeisungspflichtVerletzt	Nr. 10	€2/kW always	N/A (Abs. 3 Nr. 2)	no
MastrNichtRegistriert	Nr. 11	€10/kW/month	Yes → €2	yes
DoppelvermarktungsverbotVerletzt	Nr. 12	€10/kW/month	No	no

§52 Abs. 4 extra months: Nr. 7 (+3m), Nr. 9 (+1m), Nr. 10 (full calendar year), Nr. 12 (+6m). §52 Abs. 5 cap: simultaneous violations are capped at €10/kW/month in total.

Violation start tracking

Nr. 11 is the one §52 clock einsd owns end to end; everything else starts from a register entry.

• On registration (POST /api/v1/anlagen): mastr_registriert = false sets mastr_violation_start = heute() (the Europe/Berlin date) when not already tracked.
• On MaStR confirmation (POST .../mastr-registrierung): clears it, stopping accrual.
• Everything else: eeg_pflichtverstoesse.beginn, filed through the register.
• At settlement: run_settlement re-reads the register inside its own transaction — the way it re-reads every other running total — so no caller can settle a plant at one month's charge for a year-old breach. monate_des_verstosses then counts inclusive calendar months from the start to the earlier of the billing month and behoben_am, because §52 Abs. 2 charges for every month the breach subsists "ganz oder teilweise", and the §52 Abs. 4 tail is added on top.

---

§13a EnWG — Einspeisemanagement Compensation

When the NB curtails a plant's output (Einspeisemanagement / Redispatch 2.0), §13a EnWG requires compensation for the entgangene Einnahmen — modelled here at the AW rate. The §51 Negativpreisregel does not touch these kWh (they were never fed in).

POST /api/v1/anlagen/{tr_id}/settle/2024/6
Content-Type: application/json

{ "einspeisemenge_kwh": "850", "einspeisemanagement_kwh": "150" }

einsd adds a separate §13a EnWG position to the settlement:

• Regular kWh: 850 × rate / 100
• EInsMan compensation: 150 × AW / 100 (separate billing position)
• Total: as if 1,000 kWh were fed in

Source: §13a EnWG (Redispatch 2.0, historically §15 EEG Härtefallregelung); §51 Abs. 1 EEG 2023 (curtailed kWh explicitly excluded).

---

§21b EEG 2023 — Zuordnung zu einer Veräußerungsform, Wechsel

§21b Abs. 1 Satz 1 lists four Veräußerungsformen, and the endpoint accepts the four settlement models that name one: VERGUETUNG (Nr. 2 i.V.m. §21 Abs. 1 Satz 1 Nr. 1), AUSFALLVERGUETUNG (Nr. 2 i.V.m. Nr. 3), DIREKTVERMARKTUNG (Nr. 1, die Marktprämie nach §20) and SONSTIGE_DIREKTVERMARKTUNG (Nr. 4). AUSSCHREIBUNG is deliberately not one: it is the Marktprämie with an auction-set anzulegender Wert, and a switch request does not grant a Zuschlag.

eeg_billing::direktverm::validate_wechsel is the decision; the handler maps the settlement model onto it and renders the refusal.

Rule	Source
The change takes effect only on the first of a calendar month	§21b Abs. 1 Satz 2
The Mitteilung is due before the preceding calendar month begins — so the earliest reachable effective date is the 1st of the month after next	§21c Abs. 1 Satz 1
A plant over 100 kW may not take the Einspeisevergütung mit gesetzlich bestimmtem Wert — it may still take the Ausfallvergütung	§21 Abs. 1 Satz 1 Nr. 1
The Ausfallvergütung is closed to a plant assigned to the unentgeltliche Abnahme within the last 24 months	§21b Abs. 1 Satz 4

There is no „one switch per calendar month" rule: Satz 2 already makes a second change within one month impossible, and §21c Abs. 1 Satz 2's fünftletzter Werktag variant for the Ausfallvergütung is a Werktag rule the endpoint does not apply.

POST /api/v1/anlagen/{tr_id}/switch-veraeusserungsform
Content-Type: application/json

{
  "new_model": "DIREKTVERMARKTUNG",
  "effective_date": "2026-08-01",
  "direktvermarkter_mp_id": "9910000000001",
  "direktverm_aw_ct": "6.28"
}

Returns 422 Unprocessable Entity naming the rule that decided. last_veraeusserungsform_switch is updated on success. All subsequent settlements use the new model.

---

§§53b–54 EEG 2023 — reductions of the anzulegender Wert

These three statutes cut the anzulegender Wert itself, before any settlement formula runs. That ordering is not a detail. The gleitende Marktprämie is max(0, AW − Marktwert), floored at zero, so a euro deduction taken after the floor is a different number from a cut applied before it: where the Marktwert already exceeds the AW the premium is zero, and a post-hoc deduction would push the settlement negative — charging the operator for electricity they fed in. eeg-billing therefore applies all of them to the AW and records each as a zero-euro audit position naming its §, so a Gutschrift shows every statute that touched the rate without double-counting the money.

Only the triggering facts are stored. Every amount except §53c's is fixed by statute, so there is no rate column a data-entry error could use to invent a deduction the law does not provide for.

§	Trigger	Amount	Table
53b	A Regionalnachweis (§79a) was issued, and the AW is gesetzlich bestimmt	−0,1 ct/kWh	eeg_regionalnachweise
53c	Electricity transited through a grid and exempt from Stromsteuer	−the granted exemption	eeg_stromsteuerbefreiungen
54	Solar first-segment auction, four distinct defects	−0,3 / −0,3 / −2,5 ct/kWh, or AW → 0	eeg_sect54_solar_defekte

§53b — Regionalnachweise

"Der anzulegende Wert für Strom, für den dem Anlagenbetreiber ein Regionalnachweis ausgestellt worden ist, verringert sich bei Anlagen, deren anzulegender Wert gesetzlich bestimmt ist, um 0,1 Cent pro Kilowattstunde."

The qualifier is about how the AW was determined, not how the electricity is marketed: a statutory-AW plant in Direktvermarktung is in scope, a tender-awarded plant is not. Regionalnachweise are issued by the Herkunfts- und Regionalnachweisregister; no BNetzA certificate and no grid area is involved.

POST /api/v1/anlagen/{tr_id}/aw-reduktionen/regionalnachweis
Content-Type: application/json

{ "nachweis_ref": "HKNR-RN-2026-0001", "effective_from": "2026-01-01" }

No amount is accepted — the response echoes the statutory 0,1 ct/kWh.

§53c — Stromsteuerbefreiung

"Der anzulegende Wert verringert sich für Strom, der durch ein Netz durchgeleitet wird und der von der Stromsteuer nach dem Stromsteuergesetz befreit ist, um die Höhe der pro Kilowattstunde gewährten Stromsteuerbefreiung."

The amount is the exemption actually granted, which is why it is the one stored value here. It is capped — in the schema and again in the engine — at the full §3 StromStG rate of 20,50 EUR/MWh = 2,05 ct/kWh: an exemption cannot exceed the tax it exempts from.

The combination is narrow in practice. §9 Abs. 1 Nr. 1 and Nr. 3 StromStG both require self-consumption at, or supply in spatial connection to, the generating plant — neither of which involves grid transit. Record a row only where an exemption has actually been granted for grid-transited electricity.

POST /api/v1/anlagen/{tr_id}/aw-reduktionen/stromsteuerbefreiung
Content-Type: application/json

{
  "befreiung_ct_kwh": "2.05",
  "rechtsgrundlage": "§9 Abs. 1 Nr. 1 StromStG",
  "effective_from": "2026-01-01"
}

§54 — Ausschreibungen für Solaranlagen des ersten Segments

Solar first-segment tenders only. Four independent defects; Abs. 1 and Abs. 2 stack, and Abs. 4 zeroes the AW outright and subsumes the rest.

Absatz	Defect	Effect
1	Zahlungsberechtigung applied for only after the 18th calendar month following announcement of the Zuschlag	−0,3 ct/kWh
2	Plant location does not match, even partly, the Flurstücke named in the bid	−0,3 ct/kWh
3	Nachweis of simultaneous crop cultivation / agricultural use (§37 Abs. 1 Nr. 3, §85c Abs. 1 Satz 4) not supplied	−2,5 ct/kWh
4	Landesverordnung under §37c Abs. 2 not met	AW → 0

Abs. 3 Satz 2/3 make the deduction lapse for the future once the proof arrives, and retroactively for the periods it covers — so a late Nachweis is recorded by closing the row's validity period, not by deleting it.

POST /api/v1/anlagen/{tr_id}/aw-reduktionen/sect54-defekt
Content-Type: application/json

{ "zahlungsberechtigung_nach_18_monaten": true, "effective_from": "2026-01-01" }

A request setting no defect is refused: a row that deducts nothing is a data-entry error, not a record.

When the missing Nachweis arrives, close the period rather than deleting the row — that the plant was short for the earlier periods is what the §147 AO trail has to keep:

POST /api/v1/anlagen/{tr_id}/aw-reduktionen/sect54-defekt/{id}/nachweis-erbracht
Content-Type: application/json

{ "effective_until": "2026-07-31" }

Inspecting what is in force

A settlement shrinks silently when one of these rows exists, so the cuts are readable without settling again:

GET /api/v1/anlagen/{tr_id}/aw-reduktionen?on=2026-07-01

{
  "tr_id": "DE_TR_...",
  "stichtag": "2026-07-01",
  "reduktionen": [
    { "paragraph": "§53b EEG 2023", "grund": "Regionalnachweis (§79a EEG) ausgestellt",
      "abzug_ct_kwh": "0.1", "hinweis": "gilt nur bei gesetzlich bestimmtem anzulegendem Wert" },
    { "paragraph": "§54 Abs. 3 EEG 2023",
      "grund": "Nachweis der gleichzeitigen landwirtschaftlichen Nutzung fehlt",
      "abzug_ct_kwh": "2.5", "setzt_aw_auf_null": false }
  ]
}

---

Monthly Settlement

POST /api/v1/anlagen/DE0123456789.../settle/2024/6
Content-Type: application/json

{
  "einspeisemenge_kwh": "312.5",
  "kwh_during_negative_epex": "0",
  "negative_price_quarter_hours": 0,
  "einspeisemanagement_kwh": "0",
  "billing_days_fraction": null
}

billing_days_fraction is computed automatically (§25 Abs. 1 Satz 3) when null. Supply explicitly to override.

Response:

{
  "id": "3fa85f64-...", "billing_year": 2024, "billing_month": 6,
  "settlement_eur": "23.22", "faelligkeitsdatum": "2024-07-15", "status": "calculated",
  "positions": [
    { "description": "Einspeisevergütung §21 EEG 2023", "legal_basis": "§21 EEG 2023",
      "kwh": "312.5", "rate_ct_kwh": "7.43", "eur": "23.22" }
  ]
}

faelligkeitsdatum = 15th of the following calendar month (§26 Abs. 1 EEG 2023: „monatlich jeweils zum 15. Kalendertag für den Vormonat“).

Status	Meaning
calculated	Amount computed successfully
no_data	einspeisemenge_kwh not supplied
price_missing	The market reference the formula needs is not in the database — the Anlage 1 Marktwert (PUT /api/v1/marktwert/{year}/{art}/{erzeugungsart}) or the EPEX monthly average (PUT /api/v1/epex-monthly/{year}/{month}). Not a settled status, so the monthly worker retries it
foerderung_beendet	Förderdauer ended: the EEG Förderende passed, the § 8 KWKG lifetime Vollbenutzungsstunden are used up, or an Ausschreibungs-Zuschlag lapsed. This period was prorated
jahreskontingent_erschoepft	§ 8 Abs. 4 KWKG — this calendar year's Vollbenutzungsstunden are used up. Distinct from foerderung_beendet: the plant stays aktiv and the Förderung resumes in January
sanctioned	§52 Abs. 1 EEG ≤2021 — Vergütung = 0 (SanktionAlt::VerguetungAufNull)
kein_anspruch	The statute leaves no §19 Abs. 1 claim for this period. Two provisions reach it — see below. Terminal for the period: re-running on the same facts will not change it

kein_anspruch has two sources. §21 Abs. 1 Satz 1 Nr. 1 — a plant over 100 kW left on the Einspeisevergütung, which only a Veräußerungsformwechsel changes; the service decides that one, because which Veräußerungsform a plant is assigned to is register data. §39i Abs. 1 — a bezuschlagte Biogasanlage over its Getreide- und Mais-Höchstanteil, which the engine reports itself, because the fuel composition is handed to it.

Idempotent: re-running overwrites the previous result.

---

Batch Settlement

POST /api/v1/settle/2024/6
Content-Type: application/json

{ "dry_run": false }

{ "billing_year": 2024, "billing_month": 6, "dry_run": false,
  "total_plants": 42, "settled": 39, "skipped_no_data": 2,
  "skipped_price_missing": 1, "errors": 0,
  "total_settlement_eur": "4813.22", "results_sample": [] }

settled counts calculated and foerderung_beendet; anything other than those four statuses lands in errors. results_sample carries the first 100 settled plants.

The monthly auto-settle worker wakes on a fixed ~23 h interval and settles only from auto_settle_from_day (default the 7th) — the ÜNB publishes the Marktwert around the 5th, and running earlier writes price_missing receipts for plants that were merely early. Each sweep revisits auto_settle_catchup_months periods back (default 3, clamped 1–24), so a month the service was down for is not left unpaid.

---

Jahresabrechnung

POST /api/v1/anlagen/{tr_id}/jahresabrechnung/{year}

Derived from the stored receipts, not recomputed — the monthly runs are what created the payment obligation. Each month contributes its latest receipt: the correction where one exists, the original otherwise.

A correction is a separate row and does not supersede its original in place, so neither summing every row (which double-counts the month) nor summing only the originals (which reports superseded amounts) agrees with what was paid. Taking the latest per month does.

missing_months is bounded by the commissioning date and the Förderende, so a plant commissioned in June is not missing January — demanding all twelve would leave a plant's first and last years permanently vorlaeufig, listing months that were never owed.

---

§ 147 AO / GoBD — Correction Settlement

When meter data or tariffs are corrected, create a correction receipt:

POST /api/v1/anlagen/{tr_id}/settlements/{year}/{month}/correction
Content-Type: application/json

{
  "einspeisemenge_kwh": "340.5",
  "reason": "MeterDataCorrected",
  "reason_detail": "Corrected reading after Zählernachlesung on 2024-07-20"
}

The correction:

1. Re-runs the settlement with corrected inputs
2. Inserts a new receipt carrying is_correction = true and correction_of = <original_id>, beside the original — which stays live and unchanged
3. Writes no settlement_receipt_history snapshot, because nothing is being overwritten. That table exists for the other case: a plain re-settle of the same period, whose upsert replaces the initial row in place

CorrectionReason	Use case
MeterDataCorrected	Corrected Einspeisemenge after Zählernachlesung
TariffCorrected	Wrong verguetungssatz_ct applied
MastrRegistrationConfirmed	Retroactive §52 sanction removal after MaStR confirmed
CapacityCorrected	Wrong leistung_kwp applied
RegulatoryReprocessing	BNetzA ruling changed billing basis
FoerderendedatumCorrected	§25 Abs. 1 Satz 2 date recalculated
Other	Manual correction with free-text detail

The original receipt is preserved in place in settlement_receipts; the correction chain is queryable via correction_of. Reading "the receipt for this month" therefore means the latest row — the correction where one exists, the original otherwise.

---

§25 EEG — Anteilige Zahlung (Partial Billing Period)

When a plant is commissioned or its Förderdauer ends mid-month, only the calendar days with entitlement count. einsd computes billing_days_fraction automatically:

graph LR
    IBN["Commissioning date<br/>in current billing month?"]
    IBN -->|"Yes, day > 1"| COMM["fraction = <br/>(days_in_month - day + 1) / days_in_month"]
    IBN -->|"No"| FED["Förderendedatum<br/>in current billing month?"]
    FED -->|"Yes, day < last"| DECOM["fraction = day / days_in_month"]
    FED -->|"No"| FULL["fraction = None<br/>(full month)"]

Case	Example	billing_days_fraction
Commissioned June 15, 30-day month	16 eligible days	16/30 = 0.5333
Förderendedatum June 20, 30-day month	20 eligible days	20/30 = 0.6667
Full month	any	null (full amount)

billing_days_fraction is applied to settlement_eur and all position amounts. pflichtzahlung_eur is not prorated (penalties are per-calendar-month).

---

Repowering (§3 Nr. 30 i.V.m. §25 EEG 2023)

⚠ Implementation model, not a complete legal statement. Repowering law is nuanced: whether the Förderdauer resets, and what new tariff applies, depends on the type and extent of the repowering and the applicable EEG provisions. This endpoint models the most common full-repowering case. Always confirm the specific plant scenario with the applicable EEG provisions and BNetzA guidance.

For the full-repowering case: the Förderdauer resets from the repowering date. New foerderendedatum = December 31 of (year + 20) per §25 Abs. 1 Satz 2 EEG.

POST /api/v1/anlagen/{tr_id}/repowering
Content-Type: application/json

{ "repowering_datum": "2026-05-01", "leistung_kwp_neu": "6.2" }

eeg_gesetz and verguetungssatz_ct are updated to the current law/rate. Original inbetriebnahme is preserved in ursprungs_inbetriebnahme.

---

Zusammenlegung (§24 EEG 2023)

§24 Abs. 1 deems several plants one plant for the §19 Abs. 1 claim and the §21 Abs. 1 / §22 size determination. Because tariff bands and the tender threshold are size-dependent, a merge the statute does not support moves the survivor into a band it never qualified for — for the rest of its 20-year Förderdauer, and indistinguishably from a legitimate merge once written. The endpoint therefore evaluates §24 and refuses with 422 when it does not apply, naming the rule that decided.

Satz 1 fuses two plants only when all four hold:

1. same Grundstück, Gebäude or Betriebsgelände, or otherwise in unmittelbarer räumlicher Nähe (standort_id, or unmittelbare_raeumliche_naehe on the request),
2. gleichartige erneuerbare Energien (erzeugungsart),
3. the §19 Abs. 1 claim depends on Bemessungsleistung or installierte Leistung,
4. commissioned within twelve consecutive calendar months (inbetriebnahme).

Sätze 2–5 then override that result:

Satz	Rule
2	Biogas (not biomethane) from the same Biogaserzeugungsanlage is fused regardless of Satz 1 — including across sites and outside the window (biogaserzeugungsanlage_id)
3	Freiflächenanlagen are never fused with solar on, in or at buildings and Lärmschutzwände (solar_montage)
4	Building/Lärmschutzwand solar behind different Netzverknüpfungspunkte is not one plant (netzverknuepfungspunkt)
5	Steckersolargeräte ≤ 2 kW installed and ≤ 800 VA inverter, behind a Letztverbraucher's Entnahmestelle, are disregarded entirely

Ownership is not a criterion. Satz 1 opens "unabhängig von den Eigentumsverhältnissen", so two plants with different operators fuse just the same; a model that keyed on operator identity would under-fuse, the direction that overpays.

POST /api/v1/anlagen/{tr_id}/zusammenlegen
Content-Type: application/json

{
  "parent_tr_id": "DE_PARENT_MAIN",
  "combined_leistung_kwp": "19.0",
  "unmittelbare_raeumliche_naehe": false
}

unmittelbare_raeumliche_naehe supplies Nr. 1's second limb and is a human judgement about the pair, so it is asserted per request rather than derived. It matters only when the two standort_id values differ.

On a permitted merge the child becomes abgemeldet, the parent's foerderendedatum is unchanged (only Repowering resets it), and future settlements run on the parent alone. Update verguetungssatz_ct if the combined capacity crosses a rate band boundary. A refused merge changes nothing.

The blocks share one meter reading

A fused plant keeps a rate per block — an extension commissioned later carries its own degression step — but the grid operator meters the whole of it once. The settlement therefore splits the metered Einspeisemenge across the blocks by installed capacity, and the parts have to add back up to what was metered.

Each block's own rounded share does not do that: three equal blocks of a 1000 kWh month take 333.333 kWh each and the plant is settled for 999.999 kWh. The split is by largest remainder instead, so one block carries the remaining thousandth and the block quantities sum to the reading exactly. The hours during negative EPEX prices (§ 51) are split the same way.

A block whose Förderdauer has ended is allocated and then dropped rather than excluded from the split: its capacity still counts towards the plant, so the energy that falls to it is no longer eligible rather than redistributed to the blocks that remain.

---

EPEX Monthly Price

Required for DIREKTVERMARKTUNG and POST_EEG_SPOT:

PUT /api/v1/epex-monthly/2024/6
Content-Type: application/json

{ "avg_ct_kwh": "6.82", "source": "netztransparenz.de" }

---

180-Day Alerts

GET /api/v1/anlagen/foerderung-auslaufend?days=180

Background worker runs every 6h; emits de.eeg.anlage.foerderung-auslaufend per plant.

---

EEG Vergütungssätze Reference

The first §49 windows for Solar Aufdach Überschusseinspeisung, as eeg_verguetungssaetze seeds them. The stored column is the net rate, i.e. the gross AW less the §53 Abs. 1 deduction of 0,4 ct:

Inbetriebnahme window	≤10 kWp	>10–40 kWp	>40–1000 kWp
2023-01-01 – 2024-01-31	8.20 ct	7.10 ct	5.80 ct
2024-02-01 – 2024-07-31	8.11 ct	7.03 ct	5.74 ct
2024-08-01 – 2025-01-31	8.03 ct	6.95 ct	5.68 ct
2025-02-01 – 2025-07-31	7.94 ct	6.88 ct	5.62 ct
2026-02-01 – 2026-07-31	7.78 ct	6.73 ct	5.50 ct

The series runs to a 2030 horizon in the migration, and beyond it eeg_billing::rates::aw_ct_bei_inbetriebnahme computes any window on demand. Volleinspeisung is a separate set of rows, and non-solar technologies step down annually rather than half-yearly — see §49 EEG 2023.

See BNetzA Einspeisevergütungen.

---

Endpoints

Method	Path	Description
GET	/api/v1/einspeiser	List Anlagenbetreiber
GET	/api/v1/einspeiser/{einspeiser_id}	Fetch one Anlagenbetreiber
PUT	/api/v1/einspeiser/{einspeiser_id}	Register or update an Anlagenbetreiber (§19 UStG election, payout account)
POST	/api/v1/anlagen	Register plant
GET	/api/v1/anlagen	List plants (?malo_id=&erzeugungsart=&status=)
GET	/api/v1/anlagen/{tr_id}	Fetch plant
PUT	/api/v1/anlagen/{tr_id}	Update plant
DELETE	/api/v1/anlagen/{tr_id}	Decommission
POST	/api/v1/anlagen/{tr_id}/mastr-registrierung	Confirm MaStR → aktiv; clears §52 violation clock
POST	/api/v1/anlagen/{tr_id}/repowering	Vollrepowering — a fresh Inbetriebnahme restarts §25
POST	/api/v1/anlagen/{tr_id}/zusammenlegen	Zusammenlegung §24 EEG — refuses with 422 when §24 Abs. 1 does not fuse the pair
GET/POST	/api/v1/anlagen/{tr_id}/pflichtverstoesse	§52 Abs. 1 — read the register, or file a breach. 409 when one of that Nummer is already open
PUT	/api/v1/anlagen/{tr_id}/pflichtverstoesse/{typ}/behoben	§52 Abs. 3 Satz 1 Nr. 1 — record the cure date
GET	/api/v1/anlagen/{tr_id}/aw-reduktionen	What cuts the anzulegender Wert on ?on= (default today), with statutory amounts
POST	/api/v1/anlagen/{tr_id}/aw-reduktionen/regionalnachweis	§53b — record a Regionalnachweis period (§79a)
POST	/api/v1/anlagen/{tr_id}/aw-reduktionen/stromsteuerbefreiung	§53c — record a granted per-kWh Stromsteuerbefreiung
POST	/api/v1/anlagen/{tr_id}/aw-reduktionen/sect54-defekt	§54 — record solar first-segment defects
POST	/api/v1/anlagen/{tr_id}/aw-reduktionen/sect54-defekt/{id}/nachweis-erbracht	§54 Abs. 3 Satz 2/3 — close the period once the Nachweis arrives
GET	/api/v1/anlagen/by-malo/{malo_id}/veraeusserungsform	Veräußerungsform in force for a MaLo, plus the E_0623 Prüfschritt 540 Direktvermarktungspflicht — read by processd's NB module, which needs the bestehende form to pick the E_0622 Vorlauffrist
POST	/api/v1/anlagen/{tr_id}/switch-veraeusserungsform	§21b monthly Veräußerungsform switch
POST	/api/v1/anlagen/{tr_id}/wind-reevaluation	§36h Abs. 2 Standortgüte re-evaluation (year 6/11/16)
GET	/api/v1/anlagen/foerderung-auslaufend	Expiring within N days
POST	/api/v1/anlagen/{tr_id}/settle/{year}/{month}	Monthly settlement (§13a EnWG EInsMan + §51a QH supported)
POST	/api/v1/anlagen/{tr_id}/settlements/{year}/{month}/correction	§ 147 AO / GoBD correction receipt — written beside the original, which stays live and unchanged
POST	/api/v1/settle/{year}/{month}	Batch settle all active plants
GET	/api/v1/anlagen/{tr_id}/settlements?year=&month=&limit=	Settlement history, newest first. year and month are independent: either alone narrows, and a month without a year is that month across every year. Unknown query parameters are a 400 — a filter this endpoint cannot apply must not look like one it did
POST	/api/v1/anlagen/{tr_id}/jahresabrechnung/{year}	Annual reconciliation from the stored monthly receipts
PUT/GET	/api/v1/epex-monthly/{year}/{month}	EPEX monthly average
PUT	/api/v1/epex-spot	Bulk-load EPEX day-ahead spot prices (§51 auto-derivation)
PUT/GET	/api/v1/marktwert/{year}/{art}/{erzeugungsart}	Anlage 1 Nr. 3/4 Marktwert, art = monat | jahr (ÜNB-published)
GET	/api/v1/marktwert/{year}/nachbewertung	Months settled on a provisional Jahresmarktwert
POST	/api/v1/verguetungssatz-lookup	Tariff rate lookup
GET/POST	/mcp	MCP server (Streamable HTTP 2025-11-25)
GET	/health	Liveness
GET	/health/ready	Readiness

---

Authentication and authorization

Registering a plant or settling a month creates a payment obligation to the Anlagenbetreiber, and a correction re-opens a closed accounting period. Neither is served to whoever can reach the port.

einsd refuses to boot without an [oidc] section unless the deployment asks for that by name with allow_insecure_no_auth = true. Authentication says who is calling; Cedar says what they may do. services/einsd/policies/einsd.cedar states 11 actions in three grants, and every handler calls enforcer.check(principal, action, tenant) before it touches the database — a refusal is a 403 carrying the Cedar decision as its error.

Grant	Actions	Requires
Reads	read-anlage, read-einspeiser, read-settlement, read-marktdaten, use-mcp	a matching tenant only
Writes	write-anlage, write-einspeiser, run-settlement, manage-lifecycle, write-marktdaten	NB, LF or UENB
Corrections	correct-settlement	NB or UENB — a narrower set than an ordinary settlement run

Action	Guards
read-anlage	GET /anlagen, /anlagen/{tr_id}, /anlagen/foerderung-auslaufend, /anlagen/by-malo/{malo_id}/veraeusserungsform, and the two read-only sub-resources /pflichtverstoesse and /aw-reduktionen
write-anlage	POST/PUT/DELETE /anlagen[/{tr_id}]
read-einspeiser / write-einspeiser	the /einspeiser register
read-settlement	GET /anlagen/{tr_id}/settlements
run-settlement	POST /anlagen/{tr_id}/settle/{year}/{month}, POST /settle/{year}/{month}, POST .../jahresabrechnung/{year}
correct-settlement	POST /anlagen/{tr_id}/settlements/{year}/{month}/correction
manage-lifecycle	repowering, zusammenlegen, mastr-registrierung, switch-veraeusserungsform, the §52 Pflichtverstoß register, the §§53b–54 AW-Reduktionen and the §36h Abs. 2 Wind-Reevaluierung
read-marktdaten	GET /epex-monthly/…, /marktwert/…, /marktwert/{year}/nachbewertung, and POST /verguetungssatz-lookup — a POST because it takes a body, but a read
write-marktdaten	PUT /epex-monthly/…, PUT /epex-spot, PUT /marktwert/…
use-mcp	/mcp, applied by the shared MCP middleware

The policies test three context fields — principal_tenant and principal_roles from the mako_tenant / mako_roles JWT claims, and resource_tenant from the row's owner. Cedar is default-deny, so cross-tenant access needs no forbid clause: no policy permits it.

---

Configuration

Key	Required	Default	Description
database.url	yes	—	PostgreSQL connection string (env:… supported)
port	no	9180	HTTP listen port
tenant	yes	—	Tenant identifier — data-isolation key (any stable string; typically the operator’s BDEW- or DVGW-Codenummer)
erp_webhook_url	no	—	ERP webhook for CloudEvents
erp_hmac_secret	no	—	HMAC-SHA256 signing secret
edmd_url	no	—	edmd URL for auto-fetching Einspeisemenge
edmd_api_key	no	—	Bearer token for edmd
alert_interval_secs	no	21600	Förderendedatum alert interval (6h)
jahresmarktwert_url	no	—	ÜNB source for the monthly Marktwert import (Anlage 1 Nr. 3). The Jahresmarktwert lands once a year and is imported by hand
jahresmarktwert_import_interval_secs	no	86400	How often to poll it. The worker also runs once 60 s after startup
auto_settle_from_day	no	7	Earliest day of month the auto-settle worker settles the previous month. The ÜNB publishes the Marktwert around the 5th, so running earlier writes price_missing receipts for plants that were merely early
auto_settle_catchup_months	no	3	How many months back each sweep revisits (clamped 1–24), so a period the service was down for is not left unpaid
[mcp]	no	—	MCP /mcp authentication — an API key beside the OIDC verifier, for agent clients that mint no token (api_key = "env:EINSD_MCP_API_KEY")
[oidc]	yes	—	OIDC token verification for the REST API; required unless allow_insecure_no_auth
allow_insecure_no_auth	no	false	Serve every REST route unauthenticated — local development only

# Minimal einsd.toml
port     = 9180
tenant   = "9910000000002"
edmd_url = "http://edmd:8380"

[database]
url = "postgresql://einsd:secret@db:5432/einsd"  # or "env:DATABASE_URL"

---

Database Schema

Single consolidated schema (services/einsd/migrations/0001_schema.sql).

eeg_anlagen

One row per Technische Ressource (TR) — the generating unit, identified by an 11-character tr_id. A plant also names the Marktlokation (MaLo) it feeds into: the commercial delivery point the market settles against, identified by an 11-digit malo_id. Both formats are described under Identifier Formats. PK: (tr_id, tenant).

Column	Type	Notes
tr_id	TEXT	Technische Ressource ID
tenant	TEXT	Data-isolation key (any stable string; typically the operator's BDEW- or DVGW-Codenummer)
malo_id	TEXT	11-digit MaLo-ID
eeg_gesetz	SMALLINT	EEG law year (0, 2000, 2004, 2009, 2012, 2017, 2021, 2023)
inbetriebnahme	DATE	Commissioning date
leistung_kwp	NUMERIC	Installed peak power kWp (or kW_el for KWKG)
erzeugungsart	TEXT	SOLAR_AUFDACH, WIND_ONSHORE, BIOMASSE, …
verguetungssatz_ct	NUMERIC	Net rate ct/kWh (gross AW minus §53 deduction)
foerderendedatum	DATE?	Dec 31 of year+20 (statutory); exact 20y for Ausschreibung. NULL for a KWKG plant, which has no Förderende — § 8 KWKG caps the Zuschlag in Vollbenutzungsstunden, not on a date
settlement_model	TEXT	VERGUETUNG, DIREKTVERMARKTUNG, … (see the model table)
sect9_fernsteuerbarkeit	BOOLEAN	§9 Abs. 2 Satz 1 Nr. 1 / Nr. 2 lit. a — ferngesteuerte Reduzierung
sect9_begrenzung_60	BOOLEAN	§9 Abs. 2 Satz 1 Nr. 2 lit. b / Nr. 3 — 60 % Wirkleistungsbegrenzung
wechselrichterleistung_va	NUMERIC	§9 Abs. 2 Satz 4 — second half of the Steckersolar carve-out
leistung_kwp	NUMERIC	CHECK (> 0)
verguetungssatz_ct	NUMERIC	CHECK (>= 0)
zuschlag_erloeschen_datum	DATE	§36e/§37e/§39e: the award lapses on this date; the expiry is derived, not stored
direktverm_aw_ct	NUMERIC?	Statutory or tendered AW in ct/kWh
mieter_zuschlag_ct	NUMERIC?	Mieterstrom surcharge ct/kWh (§21 Abs. 3 EEG 2023)
mastr_registriert	BOOL	MaStR confirmed; false → §52 penalty
mastr_nummer	TEXT?	MaStR Registrierungsnummer (SEE900000012345)
einspeiser_id	TEXT	The plant's Anlagenbetreiber (FK → einspeiser, NOT NULL). The VAT status and the payout account live there, not here
status	TEXT	aktiv, foerderung_beendet, abgemeldet
inbetriebnahme_typ	TEXT?	ERSTINBETRIEBNAHME, REPOWERING, ERWEITERUNG, …
solar_montage	TEXT?	AN_GEBAEUDE_ODER_LAERMSCHUTZWAND, FREIFLAECHE, SONSTIGE — the §24 Abs. 1 Satz 3/4 distinction, not the technology
wind_guetegrad	NUMERIC?	§36h Gütegrad (e.g. 0.85 = 85% of reference yield)
wind_korrekturfaktor	NUMERIC?	§36h initial certified Korrekturfaktor
wind_guetefaktor_reevaluations	JSONB	§36h Abs. 2 re-evaluations (year 6/11/16) — the effective Korrekturfaktor per billing period is derived from these
fernsteuerbarkeit_datum	DATE?	§9 EEG Fernsteuerbarkeit installation date
direktvermarktung	BOOL	A request flag, not a derived one: true on POST /api/v1/anlagen forces settlement_model = DIREKTVERMARKTUNG whatever the body said. Nothing sets it from the capacity — the >100 kW consequence is kein_anspruch at settlement, not a silent model change
capacity_blocks	JSONB?	§24 Erweiterung blocks
settlement_state	TEXT	active, reduced, suspended, interrupted, post_eeg, ended
ausschreibungs_zuschlag_id	TEXT?	BNetzA Zuschlag-ID (e.g. "SEE-2024-001234")
is_biogas_sect51b	BOOL	§51b EEG 2023: biogas Ausschreibungsanlage (AW=0 when EPEX≤2ct)
speicher_option	TEXT	KEINE (default) · ABGRENZUNG · PAUSCHAL — § 19 Abs. 3b/3c. Anything but KEINE moves the plant onto the Jahresmarktwert (Anlage 1 Nr. 2 Satz 3)
kwk_anlagenart	TEXT?	NEU · MODERNISIERT · NACHGERUESTET — §8 Abs. 1–3; with kwk_kostenanteil it derives kwk_foerderdauer_h
kwk_verwendung	TEXT?	Which §7 Absatz prices the plant — NETZ_DER_ALLGEMEINEN_VERSORGUNG and four NICHT_EINGESPEIST_* values
kwk_bmwk_feststellung	BOOL	§7 Abs. 1 Satz 2: the 0,5 ct uplift is payable only once the BMWK published its Feststellung. false until an operator records that it did
standort_id	TEXT?	§24 Abs. 1 Satz 1 Nr. 1 — Grundstück / Gebäude / Betriebsgelände. NULL cannot establish a shared site
solar_montage	TEXT?	§24 Sätze 3/4 — AN_GEBAEUDE_ODER_LAERMSCHUTZWAND · FREIFLAECHE · SONSTIGE
netzverknuepfungspunkt	TEXT?	§24 Satz 4 — building solar behind different points is not one plant
biogaserzeugungsanlage_id	TEXT?	§24 Satz 2 — biogas from the same Biogaserzeugungsanlage is fused regardless of Satz 1
zuschlag_erloeschen_datum → award_expired	derived	Zuschlag erloschen → FoerderungBeendet, derived from the date against the billing period. Technology-specific: §36e (Wind an Land), §37e (Solaranlagen des ersten Segments), §39e (Biomasseanlagen) EEG 2023
zuschlag_erloeschen_datum	DATE?	Date the Zuschlag lapses for want of timely commissioning (§36e / §37e / §39e). Distinct from §35a Entwertung von Zuschlägen, which is a BNetzA act rather than a deadline
last_veraeusserungsform_switch	DATE?	§21b: the effective date of the last Veräußerungsform switch
mastr_violation_start	DATE?	§52: date MaStR non-registration began (auto-set on registration)
(every other §52 clock)	—	eeg_pflichtverstoesse — see §9 / §52 EEG
negative_price_qh_gesamt	BIGINT	§51a: cumulative raw quarter-hours; effektives_foerderende rounds once over the total
ist_pilotwindanlage	BOOL	§3 Nr. 37: exempt from §51 under every Fassung
sect51_optin_erklaert_am	DATE	§100: Solarspitzengesetz opt-in declared (runs from the year-end after the iMSys)
verguetungsform	TEXT	UEBERSCHUSS · VOLLEINSPEISUNG · KWK_ZUSCHLAG — part of the rate-table key
foerderung_alert_sent_at	TIMESTAMPTZ	the 180-day alert fires once per plant, not once per sweep

settlement_receipts

One initial receipt per billing period, plus any number of corrections beside it. The unique index is partial — (tr_id, tenant, billing_year, billing_month) WHERE is_correction = false — so a re-settle upserts the initial row in place while a correction is inserted as a separate row, leaving the original untouched. Upserts must repeat the predicate; Postgres cannot infer a partial index from the column list alone.

Reading "the receipt for this month" therefore means the latest row — the correction where one exists, the original otherwise (DISTINCT ON (billing_month) … ORDER BY is_correction DESC, settled_at DESC).

Column	Notes
pflichtzahlung_eur	§52 EEG 2023 penalty for this period (separate from Vergütung)
marktwert_vorlaeufig	NOT NULL DEFAULT false. The month was settled on a provisional Jahresmarktwert and is due a recomputation once the binding figure lands. Always false for a Monatsmarktwert and for the EPEX fallback
rechnung_json / gutschrift_nummer	The §14 UStG Gutschrift and its number. NULL for a non-billable status
faelligkeitsdatum	§26 Abs. 1 EEG 2023 — 15th of following calendar month
verlaengerungsanspruch_qh	§51a quarter-hours accrued this period
billing_days_fraction	§25 partial month factor (mid-month commissioning/expiry)
positions_json	§ 147 AO / GoBD — itemized billing positions JSONB snapshot
is_correction	true when this receipt supersedes a prior calculation
correction_of	UUID of the original receipt this corrects (traceability chain)

settlement_receipt_history

§ 147 AO / GoBD immutable snapshots, captured as to_jsonb(settlement_receipts) before a re-settle overwrites an initial receipt. Corrections write no snapshot — they leave the original in place. Query this table to reconstruct the billing history for a plant and period.

settlement_state_transitions

Audit log of every settlement state change: from_state, to_state, effective_from, reason.

eeg_regionalnachweise

§53b EEG 2023: periods for which a Regionalnachweis (§79a) was issued for a plant's electricity. The 0,1 ct/kWh deduction is statutory and is not stored.

eeg_stromsteuerbefreiungen

§53c EEG 2023: the per-kWh Stromsteuerbefreiung granted for grid-transited electricity, CHECK-capped at the §3 StromStG full rate of 2,05 ct/kWh.

eeg_sect54_solar_defekte

§54 EEG 2023: the four statutory defects for solar first-segment auction plants, per validity period. A row recording no defect is rejected by a CHECK.

eeg_pflichtverstoesse

§52 Abs. 1 EEG 2023: the breaches recorded against a plant. The typ CHECK is SanktionsTyp::ALL and a guard holds the two together. A partial unique index (ep_offen) allows one open entry per plant and Nummer while keeping the history — a breach recurs, and the §52 Abs. 3 Satz 1 Nr. 1 reduction reaches back to the beginning of the one being cured, not of every one that ever ran.

eeg_verguetungssaetze

Reference table for gross AW rates by technology, capacity band, and commissioning quarter.

marktwert_preise

The ÜNB Marktwerte in both Anlage 1 series, distinguished by art. billing_month is NULL for a Jahresmarktwert, which has none, and vorlaeufig marks a running estimate — only a Jahresmarktwert can be one.

epex_monthly_prices

EPEX Spot monthly averages. The fallback inside a series when no marktwert_preise row matches, and the basis for POST_EEG_SPOT.

---

CloudEvents Emitted

Type	When	Key payload fields
de.eeg.verguetung.berechnet	FEED_IN_TARIFF / POST_EEG settled	tr_id, billing_year, billing_month, settlement_eur (net), pflichtzahlung_kumuliert_eur (the running §52 claim, not a monthly increment — a later receipt supersedes an earlier one), gutschrift_nummer, gutschrift_steuer_eur, gutschrift_brutto_eur, bank_iban, bank_bic, zahlungsempfaenger
de.eeg.marktpraemie.berechnet	MARKET_PREMIUM settled (DIREKTVERMARKTUNG, AUSSCHREIBUNG)	the same payload — one builder serves both types, and the type is what says which model settled
de.eeg.anlage.mastr-registriert	MaStR confirmed	tr_id, mastr_nummer
de.eeg.anlage.foerderung-auslaufend	EEG Förderung ending ≤180 days. Never for a KWKG plant, which has no foerderendedatum to count down to	tr_id, foerderendedatum, days_remaining
de.eeg.veraeusserungsform.gewechselt	§21b switch accepted — enqueued in the same transaction as the plant update, so the switch and its §21c notification commit together	tr_id, the new model, the effective date
de.eeg.settlement.batch-due	The monthly settlement batch is due	billing_year, billing_month

bank_iban, bank_bic, and zahlungsempfaenger are forwarded from the plant's einspeiser record so accountingd can generate a SEPA Credit Transfer pain.001 without a secondary DB lookup. They are absent (null) for EIGENVERBRAUCH settlements (no payout).

§14 UStG Gutschrift document

EEG feed-in is settled under the Gutschriftverfahren (§14 Abs. 2 Satz 2 UStG): the Netzbetreiber issues the settlement document to the Anlagenbetreiber. The settlement amount alone is not that document — VAT law requires a Gutschrift with the per-rate USt breakdown (EN 16931 BG-23). For every billable settlement run_settlement therefore builds one (eeg-billing's settlement_to_gutschrift, VAT from the operator's declared einspeiser.ust_status: Regelbesteuerung 19 % category S / §19 Kleinunternehmer 0 % category E) and persists it as a BO4E rubo4e::current::Rechnung in settlement_receipts.rechnung_json, with the gutschrift_nummer (GS-EEG-<tr>-<year>-<month>) for lookup. The event carries the net (settlement_eur), the USt (gutschrift_steuer_eur) and the brutto so accountingd books the credit against an actual document, not just an amount. Non-billable statuses (no_data / price_missing / foerderung_beendet) issue no Gutschrift.

The Gutschrift crosses the BO4E outbound gate before it is stored. eeg-billing checks its own emissions in tests, but that covers the shapes the builder produces, not the values a settlement run supplies — the entitlement, the VAT status, the §§53b–54 levy layers — and every rule the gate runs is arithmetic over those. This is the document an Anlagenbetreiber is paid against. One that fails is dropped with a warning naming the defect and the settlement is stored without a document, the same degradation an assembly failure takes.

{
  "specversion": "1.0",
  "type":        "de.eeg.verguetung.berechnet",
  "source":      "urn:mako:einsd:tenant:9910000000002",
  "id":          "a1b2c3d4-...",
  "subject":     "TR-SOLAR-001",
  "data": {
    "tr_id":           "TR-SOLAR-001",
    "malo_id":         "51238696012",
    "billing_year":    2026,
    "billing_month":   7,
    "settlement_model": "VERGUETUNG",
    "einspeisemenge_kwh": "280.500",
    "settlement_eur":  "22.736",
    "status":          "calculated",
    "gutschrift_nummer":    "GS-EEG-TR-SOLAR-001-2026-07",
    "gutschrift_steuer_eur": "4.31984",
    "gutschrift_brutto_eur": "27.05584",
    "bank_iban":       "DE89370400440532013000",
    "bank_bic":        "COBADEFFXXX",
    "zahlungsempfaenger": "Franz Huber"
  }
}

All events: application/cloudevents+json + Standard Webhooks signature.

---

MCP Server

At /mcp (Streamable HTTP 2025-11-25). Auth: Authorization: Bearer <mcp_api_key>.

19 tools: list_plants · get_plant · list_expiring · list_settlements · lookup_verguetungssatz · lookup_statutory_rate · trigger_settle · list_unsettled_plants · get_epex_monthly_price · import_epex_monthly_price · get_compliance_status · list_plants_without_mastr · check_einspeiseverguetung_anspruch · check_sect44b_quota · import_marktwert · get_marktwert · get_settlement_state_history · explain_settlement · get_aw_reduktionen

Tool	Description
check_einspeiseverguetung_anspruch	Lists active plants >100 kW on the Einspeisevergütung. §21 Abs. 1 Satz 1 Nr. 1 grants that claim only bis zu 100 kW, so they settle kein_anspruch until the Veräußerungsform changes
check_sect44b_quota	Returns annual biogas production cap, YTD kWh, remaining quota, and alerts at 75 % (WARNING) and 90 % (CRITICAL) exhaustion (§44b EEG 2023, plants >100 kW).

check_einspeiseverguetung_anspruch is not a §52 case: Nr. 4 charges a §10b breach, which only a plant in Direktvermarktung can commit — and a plant on the Einspeisevergütung is not in a Direktvermarktung.

6 prompts: register-eeg-plant · settle-monthly · check-foerderung-expiry · ausschreibung-workflow · post-eeg-transition · anlagenerweiterung

The eeg-agent specialist in agentd handles de.eeg.* CloudEvents and de.messwert.reading.direct.stored (for iMSys rollout detection — lifts the <100 kW §51 Negativpreisregel exemption on first iMSys push). Two more agentd specialists cover einsd: eeg-compliance-agent runs the §52/§44b/§21 compliance checks (get_compliance_status, check_sect44b_quota, check_einspeiseverguetung_anspruch); einsd-batch-agent drives the monthly settlement batch + §52 Pflichtzahlungen sweep (list_unsettled_plants + POST /api/v1/settle/{year}/{month}, triggered on de.eeg.anlage.foerderung-auslaufend or manual/cron). See agentd operator guide for the full trigger→action mapping.

---

Testing

The eeg-billing engine is covered across four suites:

Suite	Coverage
eeg-billing lib tests	Settlement formulas, §52 cap, positions-sum invariant
prop_tests (proptest)	INV-1–INV-10: FeedInTariff exactness, MarketPremium non-negativity, §51 bounds, API contract, PostEeg floor
regulatory_showcase	§51/§51a/§51b, §52, §53b, §100 rules, all schemes, Bestandsschutz, InbetriebnahmeTyp lifecycle, §40–41 Wasserkraft, §37a Stecker-PV
eeg-billing doctests	EegGesetz::from_db_year, rate helpers, foerderendedatum

cargo test -p eeg-billing -p einsd --all-features