einsd Operator Guide

einsd operator guide — Einspeiser Registry + EEG/KWKG Settlement daemon. 12 settlement models, date-keyed §51 Negativpreisregel incl. the Solarspitzengesetz, EEG version-aware Bestandsschutz, Anlage 1 gleitende Marktprämie, §49 semi-annual solar degression, §36h Wind Korrekturfaktor, §42b EnWG GGV Messkonzept, §52 Pflichtzahlungen + §52 Abs. 6 Netting, SettlementPeriodState lifecycle, Repowering (§3 Nr. 30 i.V.m. §25), Zusammenlegung §24, KWKG Förderdauer, §14 UStG Gutschrift, §§53b–54 AW-Reduktionen, 19 MCP tools, eeg-agent.

`einsd` — Einspeiser Registry + EEG/KWKG Settlement

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 10 settlement schemes and all generation technology types.

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 /feed-in) + kWh"]
    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/>§39n feste Marktprämie<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<br/>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 /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.anlage.settlement_state_changed"| erp
    einsd -->|"de.eeg.anlage.foerderung-auslaufend<br/>de.eeg.anlage.created"| agentd

Port: :9180

Why `einsd` Exists

German EEG/KWKG law requires every Netzbetreiber (NB) to:

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.
Verify MaStR registration before releasing Vergütung payments (§52 EEG 2023 / old §47 EEG 2021 via §100 Übergangsregelung).
Calculate monthly remuneration per the applicable settlement model and EEG version.
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.
Alert the asset owner ≥180 days before the Förderendedatum.
Emit CloudEvents to the ERP system for payment dispatch and accounting entries.

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 seeded with the Startwerte as enacted:

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.

Generator Types (`erzeugungsart`)

Value	Technology	Legal basis
`SOLAR_AUFDACH`	Rooftop PV	§21 + §48 EEG 2023
`SOLAR_FREIFLAECHE`	Ground-mounted PV	§28 EEG 2023
`SOLAR_AGRIPV`	Agri-PV	§37 Abs. 1 Nr. 3 + §48 EEG 2023
`SOLAR_MIETERSTROM`	Building community solar	§21 Abs. 3 EEG 2023
`SOLAR_STECKER`	Balkonkraftwerk <800 W	§9 EEG 2023
`WIND_ONSHORE`	Wind onshore	§§21, 28, 36 EEG 2023
`WIND_OFFSHORE`	Wind offshore	§§70ff EEG 2023
`BIOMASSE` / `BIOMASSE_HOLZ`	Solid biomass	§42 EEG 2023
`BIOGAS` / `BIOMETHAN`	Fermentation / upgraded gas	§42 EEG 2023
`KLAEGAS` / `GRUBENGAS` / `DEPONIEGAS`	Sewage / mine / landfill gas	§41 EEG 2023
`WASSERKRAFT`	Hydro	§40 EEG 2023
`GEOTHERMIE` / `GEZEITEN`	Geothermal / tidal	§§45–46 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. 12,91 ct/kWh for a ≤ 10 kWp roof plant.

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.

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 Nr. 2 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 Nr. 3.1.2 defines the Marktprämie as the anzulegender Wert minus the Monatsmarktwert, floored at zero:

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

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 Monatsmarktwert 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 KWKG 2023, from 01.01.2023):

Plant size	KWK-Zuschlag	Förderdauer
≤50 kW_el	8.00 ct/kWh	20 years
50–100 kW_el	6.00 ct/kWh	20 years
100–250 kW_el	5.00 ct/kWh	20 years
250 kW–2 MW_el	4.00 ct/kWh	10 years
>2 MW_el	3.00 ct/kWh	30,000 full-load hours

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.

Plant Lifecycle

stateDiagram-v2
    [*] --> aktiv : POST /anlagen
    aktiv --> aktiv : POST /repowering<br/>(fresh Inbetriebnahme, keeps settling)
    aktiv --> foerderung_beendet : KWKG hour limit reached
    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
    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 KWKG kWh limit has been reached.
`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.

Inbetriebnahmeprozess

Physical commissioning by operator.
NB registers in einsd via POST /api/v1/anlagen (mastr_registriert: false if pending).
Operator registers plant at marktstammdatenregister.de.
NB confirms via POST /api/v1/anlagen/{tr_id}/mastr-registrierung → plant → aktiv.
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 solar: 8.51 ct gross AW (Solarpaket I) − 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:

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

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.

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, and it decides the VAT on every feed-in Gutschrift issued to them (`KLEINUNTERNEHMER` → 0 %, EN 16931 category `E`; `REGELBESTEUERUNG` → 19 %, category `S`). § 12 Abs. 3 UStG (the 0 % on PV hardware supply) is not a feed-in category and never appears here
`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

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` without an hour or year limit	§8 KWKG bounds the Zuschlag by one or the other; with neither it never ends
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 twelve Pflichtverstöße. Each charges the operator 10 €/kW per calendar month (Abs. 2), drops to 2 € once the obligation is met (Abs. 3), is capped at 10 €/kW in total (Abs. 5) and may be netted against the Vergütung (Abs. 6).

einsd derives the five the plant record can actually establish, in one place (sect52::derive_pflichtverstoesse), and feeds them all into the settlement:

§52 Abs. 1	Violation	Derived from
Nr. 1	§9 Steuerbarkeit not satisfied	`sect9_erfuellung` × capacity × technology
Nr. 4	§10b Direktvermarktungspflicht	capacity > 100 kW on an Einspeisevergütung model
Nr. 5	Ausfallvergütung past its Höchstdauer	the settlement receipts
Nr. 9	§21c switch not notified	`veraeusserungsform_notification_sent_at`
Nr. 11	MaStR registration missing	`mastr_registriert`

The remaining seven (Nr. 2, 3, 6, 7, 8, 9a, 10, 12) turn on facts einsd does not hold — storage behaviour, metering resolution, Doppelvermarktung. Record them on the plant's notes and settle a correction.

§9 is staged by capacity

The Steuerbarkeit obligation is not a single threshold:

Installed capacity	Obligation	Basis
Steckersolargerät < 2 kW (≤ 800 VA)	none	§9 Abs. 1 Satz 2
< 25 kW	60 % Leistungsbegrenzung	§9 Abs. 2 Nr. 3
25 kW – < 100 kW	Fernsteuerbarkeit or the 60 % Leistungsbegrenzung	§9 Abs. 2 Nr. 2
≥ 100 kW	Fernsteuerbarkeit; the 60 % route is not available	§9 Abs. 2 Nr. 1

Each plant therefore records how it satisfies §9, not merely when a Fernsteuerbarkeit was installed:

{ "sect9_erfuellung": "LEISTUNGSBEGRENZUNG_60" }

KEINE (the default) is a Nr. 1 violation wherever §9 requires anything, so a compliant plant has to say which route it took.

§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 §60 Abs. 2 MsbG 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 (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.

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.

§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 — but the receipt now 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.

§23a EEG 2023 — Quarterly Solar PV Degression

Solar PV tariff rates decrease quarterly. The eeg-billing crate provides the degression formula; actual BNetzA-published quarterly rates are stored in eeg_verguetungssaetze.

Solarpaket I reference rates (Q2 2024, §48 EEG 2023 n.F.):

Capacity	Überschusseinspeisung	Volleinspeisung
≤10 kWp	8.51 ct/kWh	13.31 ct/kWh
≤40 kWp	7.43 ct/kWh	11.23 ct/kWh
≤100 kWp	7.64 ct/kWh	12.74 ct/kWh
≤400 kWp	7.64 ct/kWh	10.84 ct/kWh
≤1 MWp	7.64 ct/kWh	9.54 ct/kWh

For plants commissioned after Q2 2024, use lookup_statutory_rate MCP tool or GET /api/v1/verguetungssatz-lookup to retrieve the correctly degresssed rate for the commissioning quarter.

§49 degression. 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.

§§20–22 EEG 2023 — Direktvermarktung

Mandatory threshold (§20)

Plants > 100 kW installed capacity must participate in Direktvermarktung. Plants that fail to do so while above the threshold trigger DirektvermarktungspflichtVerletzt (§52 Abs. 1 Nr. 4). Use the AUSFALLVERGUETUNG model for plants whose Direktvermarkter is temporarily unavailable (Ausfallvergütung per §21 Abs. 1 Nr. 2 EEG 2023 — TemporaryFeedInTariff is this library's abstraction for the statutory fallback remuneration).

Ausschreibungspflicht (§22)

Technology	Threshold
Solar PV	> 1,000 kWp
Wind onshore	> 750 kW
Biomasse	> 150 kW
Wasserkraft	> 500 kW
Geothermie	> 150 kW
Wind offshore	always

Plants above these thresholds 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 (arbeitsmenge_kwh, or the ¼h /feed-in series for §51), so the settlement engine never re-derives the metering split:

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`?
`FernsteuerbarkeitmFehlend`	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
`DirektvermarktungspflichtVerletzt`	Nr. 4	€10/kW/month	Yes → €2	yes
`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

On registration (POST /api/v1/anlagen): mastr_registriert = false sets mastr_violation_start = CURRENT_DATE when not already tracked.
On MaStR confirmation (POST .../mastr-registrierung): clears it, stopping accrual.
At settlement: monate_des_verstosses counts inclusive calendar months from the start date, because §52 Abs. 2 charges for every month the breach subsists "ganz oder teilweise".

§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 — Veräußerungsform Wechsel

Plants switch between Einspeisevergütung and Direktvermarktung monthly. Rules enforced:

Plants > 100 kW cannot switch back to Einspeisevergütung (mandatory Direktvermarktung, §20 EEG 2023).
Only one switch per calendar month is permitted (§21b / §21c EEG 2023).
Effective date must be the 1st of a calendar month.

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 when:

PflichtgemasseDirektvermarktung — plant > 100 kW cannot revert
AlreadySwitchedThisMonth — switch already performed this calendar month

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 }
  ]
}

§51a EEG 2023 — Verlängerungsanspruch (Förderzeitraum extension)

Every §51 reduction accrues an extension entitlement. Pass negative_price_quarter_hours explicitly, or let the auto-derivation (see §51 Negativpreisregel) supply it from the ¼h feed-in:

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

{
  "einspeisemenge_kwh": 1000,
  "kwh_during_negative_epex": 80,
  "negative_price_quarter_hours": 12
}

einsd accrues the raw lost quarter-hours per plant in negative_price_qh_gesamt. The rounding is applied once over the 20-year total at settle time (never per month, which would over-count), and effektives_foerderende derives the extended end — the stored statutory foerderendedatum is left untouched:

Solar PV: the ceil(qh / 2) Volllastviertelstunden contingent, drawn down month by month at the statutory monthly-table rate (§51a Abs. 2 EEG 2023).
All others: the lost quarter-hours rounded up to whole calendar days (96 QH/day, §51a Abs. 1 Satz 2).

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`	EPEX price needed; import via `PUT /api/v1/epex-monthly/{year}/{month}`
`foerderung_beendet`	Förderdauer ended; this period was prorated
`sanctioned`	§52 Abs. 1 EEG ≤2021 — Vergütung = 0 (`SanktionAlt::VerguetungAufNull`)

Idempotent: re-running overwrites the previous result.

Batch Settlement

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

{ "dry_run": false }

{ "total_plants": 42, "settled": 39, "skipped_no_data": 2,
  "skipped_price_missing": 1, "total_settlement_eur": "4813.22" }

The monthly auto-settle background worker triggers daily (settles previous month on or after the 2nd — §26 EEG: payments due by 15th of following month).

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:

Snapshots the original receipt to settlement_receipt_history (immutable, § 147 AO / GoBD)
Re-runs settlement with corrected inputs
Stores is_correction = true and correction_of = <original_id> in the new receipt

`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 always preserved in settlement_receipt_history. The correction chain is queryable via correction_of.

§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:

same Grundstück, Gebäude or Betriebsgelände, or otherwise in unmittelbarer räumlicher Nähe (standort_id, or unmittelbare_raeumliche_naehe on the request),
gleichartige erneuerbare Energien (erzeugungsart),
the §19 Abs. 1 claim depends on Bemessungsleistung or installierte Leistung,
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.

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

Gross AW for solar PV roof installations (§48 EEG 2023). Net rate = AW − 0.4 ct (§53).

Period	≤10 kWp AW	10–40 kWp AW	Source
2023-02 to 2024-04	8.11–8.20 ct	6.79–7.10 ct	EEG 2023 initial
from 2024-05 (Solarpaket I)	8.51 ct	7.43 ct	BGBl I 2024 Nr. 107

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`	`/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 — 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 (original preserved in history)
`POST`	`/api/v1/settle/{year}/{month}`	Batch settle all active plants
`GET`	`/api/v1/anlagen/{tr_id}/settlements`	Settlement history
`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/jahresmarktwert/{year}/{month}/{erzeugungsart}`	§20 Abs. 2 Jahresmarktwert (ÜNB-published)
`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

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 §20 Abs. 2 Jahresmarktwert import
`jahresmarktwert_import_interval_secs`	no	—	How often to poll it
`auto_settle_from_day`	no	—	Day of month the auto-settle worker may start. 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 — API key, OIDC, or dev mode (`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. 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
`settlement_model`	TEXT	`VERGUETUNG`, `DIREKTVERMARKTUNG`, … (see the model table)
`sect9_erfuellung`	TEXT	§9: `KEINE` · `FERNSTEUERBARKEIT` · `LEISTUNGSBEGRENZUNG_60`
`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?	`GEBAEUDE`, `FREIFLAECHE`, `AGRI_PV`, `STECKER_PV`, …
`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	`true` for plants > 100 kW (auto-set on creation)
`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)
`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: date of last Veräußerungsform switch (monthly guard)
`mastr_violation_start`	DATE?	§52: date MaStR non-registration began (auto-set on registration)
`fernsteuerbarkeit_violation_start`	DATE?	§52: date Fernsteuerbarkeit violation began
`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

Views: eeg_anlagen_mastr_ausstehend · eeg_anlagen_fernsteuerbarkeit_ausstehend · eeg_anlagen_direktverm_pflicht

`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)
`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_verguetungssaetze`

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

`epex_monthly_prices`

EPEX Spot monthly averages. Required for DIREKTVERMARKTUNG, AUSSCHREIBUNG and 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_eur`, `gutschrift_nummer`, `gutschrift_steuer_eur`, `gutschrift_brutto_eur`, `bank_iban`, `bank_bic`, `zahlungsempfaenger`
`de.eeg.marktpraemie.berechnet`	MARKET_PREMIUM settled	+ `epex_avg_ct_kwh`, `aw_ct`, `effective_aw_ct`
`de.eeg.anlage.mastr-registriert`	MaStR confirmed	`tr_id`, `mastr_nummer`
`de.eeg.anlage.foerderung-auslaufend`	Förderung ending ≤180 days	`tr_id`, `foerderendedatum`, `days_remaining`
`de.eeg.anlage.settlement_state_changed`	State machine transition	`tr_id`, `from_state`, `to_state`, `reason`

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_direktvermarktung_compliance · check_sect44b_quota · import_jahresmarktwert · get_jahresmarktwert · get_settlement_state_history · explain_settlement · get_aw_reduktionen

Tool	Description
`check_direktvermarktung_compliance`	Lists active plants >100 kW settled under a non-Direktvermarktung scheme (§3 Nr. 1 + §20 EEG 2023). These are §52 Abs. 1 Nr. 4 violation candidates — Abs. 2 is the 10 €/kW rate, not the list of breaches.
`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).

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/§20 compliance checks (get_compliance_status, check_sect44b_quota, check_direktvermarktung_compliance); einsd-batch-agent drives the monthly settlement batch + §52 Pflichtzahlungen sweep (list_unsettled_plants + POST /settlements/batch, 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

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