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/>§20 Abs.3 Managementprämie<br/>§23a 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/>sect53b_reductions · sect54_reductions<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:

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 version-specific §51 rules (Negativpreisregel) — thresholds differ by EEG law year; old plants (Bestandsanlagen) keep their original rules via Bestandsschutz.
5. Alert the asset owner ≥180 days before the Förderendedatum.
6. Emit CloudEvents to the ERP system for payment dispatch and accounting entries.

---

EEG Version-aware Architecture

Every plant has an eeg_gesetz column that determines which version's rules apply. The eeg-billing library exposes an EegGesetz enum (8 variants) that encodes all version-specific behaviour:

EegGesetz::Kwkg       — KWKG plants (no §51/§52 EEG 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 2025/2026 variant requires only one new enum variant — the Rust compiler enforces exhaustive handling in all match sites across the codebase.

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 table below shows the §51 Negativpreisregel thresholds per EEG version (one of the most version-sensitive rules). Other rules may differ independently.

Commissioned	§51 Negativpreisregel
before 2016-01-01	none (§100 Abs. 1 Satz 4 EEG 2017)
2016-01-01 – 2020-12-31	≥6h; Wind <3 MW; other <500 kW (EEG 2017)
2021-01-01 – 2022-12-31	≥4h; all types <500 kW (EEG 2021)
2023-01-01 +	any negative period; <100 kW (EEG 2023)

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) and eeg-billing automatically derives the correct EegGesetz for §51/§52 dispatch — preventing silent miscalculations when eeg_gesetz is set incorrectly in the DB.

graph LR
    TR["TariffSource::Transitional(rule)"]
    TR -->|"Pre2016Bestandsschutz"| E12["Eeg2012<br/>§51 never applies<br/>(§100 Abs. 1 Satz 4 EEG 2017)"]
    TR -->|"Eeg2017Negativpreis6h<br/>BiomassOldFuelClassContinuation<br/>SmallBiomassBelow150kw"| E17["Eeg2017<br/>≥6h threshold<br/>3MW/500kW exemption"]
    TR -->|"OldPlantBeforeEeg2023"| E21["Eeg2021<br/>≥4h threshold<br/>500kW exemption (all types)"]
    TR -->|"other rules"| EC["caller's eeg_gesetz"]

Paragraph100Rule	Effective EegGesetz	Source
Pre2016Bestandsschutz	Eeg2012 — §51 never applies	§100 Abs. 1 Satz 4 EEG 2017
Eeg2017Negativpreis6h	Eeg2017 — ≥6h, 3MW/500kW	§100 Abs. 2 Nr. 13 EEG 2021
BiomassOldFuelClassContinuation	Eeg2017 — old §42–44 fuel rules	§100 Abs. 6 EEG 2023
SmallBiomassBelow150kw	Eeg2017 — small biomass FiT	§100 Abs. 11 EEG 2023
OldPlantBeforeEeg2023	Eeg2021 — ≤4h, 500kW (all types)	§100 Abs. 1 EEG 2023
all other rules	caller's eeg_gesetz as-is	—

This is enforced by SettleInput::effective_eeg_gesetz() 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.

---

Generator Types (erzeugungsart)

Value	Technology	Legal basis
SOLAR / SOLAR_AUFDACH	Rooftop PV	§21 + §48 EEG 2023
SOLAR_FREIFLAECHE	Ground-mounted PV	§28 EEG 2023
SOLAR_AGRIPV	Agri-PV	§51a 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

The ErzeugungsArt enum in eeg-billing drives version-specific §51 dispatch: EEG 2017 wind turbines get the 3 MW exemption (§51 Abs. 3 Nr. 1 EEG 2017), while solar/ biomasse plants get the 500 kW exemption (Nr. 2). Under EEG 2021 both use 500 kW.

---

Settlement Models

einsd supports 10 settlement schemes via the eeg-billing crate. The scheme is stored as settlement_model in settlement_receipts and selected when calling POST /settle/{year}/{month}.

SettlementScheme	Regulation	Formula	CloudEvent
FEED_IN_TARIFF	§21 EEG	kwh × verguetungssatz_ct / 100	de.eeg.verguetung.berechnet
TENANT_ELECTRICITY	§21 Abs. 3 EEG 2023	kwh × (verguetung + mieter_zuschlag) / 100	de.eeg.verguetung.berechnet
MARKET_PREMIUM	§20 EEG	see §20 Abs. 3 note below	de.eeg.marktpraemie.berechnet
MARKET_PREMIUM + TariffSource::Auction	§§22a,28 EEG	same formula, AW from BNetzA tender	de.eeg.marktpraemie.berechnet
POST_EEG	post-20yr §21b	kwh × EPEX_avg_ct / 100 (configurable floor)	de.eeg.verguetung.berechnet
EIGENVERBRAUCH	§21 Abs. 3 EEG	EUR 0 (no feed-in remuneration)	(none)
KWK_SURCHARGE	§7 KWKG 2023	eligible_kwh × rate / 100 (hour-limit cap)	de.eeg.verguetung.berechnet
FLEXIBILITY_PREMIUM	§50b EEG 2023	kwh × (verguetung + flex_praemie) / 100	de.eeg.verguetung.berechnet
FLEXIBILITY_SURCHARGE	§50a EEG 2023	kw × rate_eur_per_kw / 12 (capacity payment)	de.eeg.verguetung.berechnet
TEMPORARY_FEED_IN_TARIFF	§21 Abs. 1 Nr. 2 EEG 2023	kwh × verguetungssatz_ct / 100 (at reduced rate)	de.eeg.verguetung.berechnet
SONSTIGE_DIREKTVERMARKTUNG	§21a EEG	EUR 0 EEG payment (revenue on the open market)	(none)

Ausschreibung is not a separate scheme. It is MARKET_PREMIUM with tariff_source = Auction — it uses the MarketPremium calculation with an auction-determined anzulegender Wert. Award validity, reductions, and revocation are the caller's responsibility; the library receives the already-resolved AW from the caller.

§20 Abs. 3 EEG 2023 — Managementprämie

This library's implementation follows the reading that the Managementprämie is incorporated into the AW before computing the spread, based on the statutory text: §20 Abs. 3 EEG 2023: "Bei der Berechnung der Marktprämie ist der anzulegende Wert um 0,4 ct/kWh zu erhöhen."

eff_AW = direktverm_aw_ct + managementpraemie_ct
Marktprämie = max(0, eff_AW − EPEX_avg) × kwh / 100

When EPEX > eff_AW, the total payment is zero — no guaranteed floor. Auto-calculated from leistung_kwp when managementpraemie_ct is null: 0.4 ct/kWh (≤100 MW) · 0.2 ct/kWh (>100 MW).

⚠ Settlement positions vs. legal components. For audit transparency, eeg-billing decomposes the total spread into two billing positions: "Gleitende Marktprämie" and "Managementprämie". This is a software decomposition to make the calculation auditable — it does not mean the Managementprämie is a legally separate payment component. The single payment to the operator is max(0, eff_AW − EPEX) × kwh / 100.

⚠ Verify before production use. The treatment of the Managementprämie in the context of current BNetzA guidance and bilateral contract terms should be confirmed against the current statutory text before relying on this calculation for settlement disputes.

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
    [*] --> angemeldet : POST /anlagen<br/>(mastr_registriert=false)
    [*] --> aktiv : POST /anlagen<br/>(mastr_registriert=true)
    angemeldet --> aktiv : POST /mastr-registrierung<br/>§52 penalty accrues until then
    aktiv --> repowered : POST /repowering (§22 EEG)
    aktiv --> foerderung_beendet : billing_date > foerderendedatum<br/>or KWKG hour limit
    aktiv --> abgemeldet : DELETE /anlagen
    angemeldet --> abgemeldet : DELETE /anlagen

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
angemeldet	Plant commissioned, MaStR pending. §52 penalty accrues.
aktiv	MaStR confirmed. Vergütung flows normally.
foerderung_beendet	20-year Förderdauer expired, or KWKG hour-limit reached.
repowered	Historical record after §22 repowering.
abgemeldet	Decommissioned.

---

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":            "51238696780",
  "eeg_gesetz":         2023,
  "inbetriebnahme":     "2024-06-01",
  "leistung_kwp":       9.8,
  "erzeugungsart":      "SOLAR_AUFDACH",
  "verguetungssatz_ct": 8.11,
  "settlement_model":   "FEED_IN_TARIFF",
  "mastr_registriert":  true,
  "mastr_nummer":       "SEE900000012345",
  "bank_iban":          "DE89370400440532013000",
  "zahlungsempfaenger": "Max Mustermann",
  "ust_status":         "KLEINUNTERNEHMER"
}

ust_status is the operator's declared VAT status — KLEINUNTERNEHMER (§19 UStG, 0 %, EN 16931 category E) or REGELBESTEUERUNG (§12 Abs. 1 UStG, 19 %, category S) — and drives the feed-in Gutschrift VAT. It is a property of the operator, not the plant, so it cannot be inferred from capacity; when omitted, einsd seeds a sensible default (a ≤30 kWp post-2023 solar plant → KLEINUNTERNEHMER, everything else → REGELBESTEUERUNG). §12 Abs. 3 UStG (the 0 % on PV hardware supply) is not a feed-in category and never appears here.

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" }

Transitions angemeldet → aktiv. Emits de.eeg.anlage.mastr-registriert.

---

§51 EEG — Negativpreisregel

During negative EPEX Spot periods, the EEG Vergütung is reduced to zero. Rules differ by EEG version — Bestandsschutz protects old plants commissioned before 2016-01-01.

graph LR
    subgraph Bestandsschutz
        A["before 2016-01-01<br/>EEG ≤2012<br/>§51 does NOT apply<br/>(§100 Abs. 1 Satz 4 EEG 2017)"]
    end
    subgraph EEG2017["EEG 2017 (2016–2020)"]
        B["≥6 consecutive hours<br/>Wind: < 3 MW exempt<br/>Other: < 500 kW exempt"]
    end
    subgraph EEG2021["EEG 2021 (2021–2022)"]
        C["≥4 consecutive hours<br/>All plants < 500 kW exempt<br/>(wind exception removed)"]
    end
    subgraph EEG2023["EEG 2023 (2023+)"]
        D["Any negative period<br/>< 100 kW exempt until iMSys<br/>(§51 Abs. 2 Nr. 1)"]
    end

The reduction is driven by two inputs on the settle request — the feed-in that fell in 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 and the monthly auto-settle) that does not carry explicit values fetches the plant's ¼h feed-in from edmd (GET /api/v1/feed-in/{malo_id}), overlays it against the stored prices, and derives them via the version-aware run logic (EEG 2017 ≥6 h, EEG 2021 ≥4 h consecutive, EEG 2023 any interval) 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 }, … ] }

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. The engine then applies the kW / iMSys 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: FEED_IN_TARIFF, TENANT_ELECTRICITY, FLEXIBILITY_PREMIUM. Not to: MARKET_PREMIUM, POST_EEG, KWK_SURCHARGE, EIGENVERBRAUCH.

§51a — Verlängerung des Vergütungszeitraums

For the quarter-hours where §51 reduced the AW to null, the Förderdauer is extended (§51a Abs. 1 Satz 2 / Abs. 2). 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 ceil(qh / 2) Volllastviertelstunden contingent, drawn down month by month at the statutory rate (Abs. 2 monthly table).
• 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.

§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/>eff_AW = AW + Managementprämie<br/>Prämie = max(0, eff_AW - EPEX) 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.

---

§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.

§23a degression tiers (based on previous year's installed GW):

Previous year PV	Degression	Example
≤9 GW	0.00%	no change
9–12 GW	0.25%/quarter	typical 2022
13–14 GW	1.00%/quarter	typical 2023
>15 GW	1.50%/quarter (max)	typical 2024/2025

---

§§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 TEMPORARY_FEED_IN_TARIFF scheme 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_pflicht and capacity_blocks columns track this.

Recording Direktvermarktung periods

The direktvermarktung_perioden JSONB column stores the history of Direktvermarktung engagements per plant. Each entry: { beginn_datum, ende_datum, direktvermarkter_mp_id, ist_freiwillig, anzulegender_wert_ct }. Sorted by beginn_datum ascending.

---

Multi-Meter Messkonzept

German EEG plants can have multiple measurement points. einsd stores only the metering classification on the plant (metering_mode = SLP / RLM / IMSYS); 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 — Compliance Violations

Old plants (EEG ≤2021 via §100 Übergangsregelung)

Old plants use the three-tier SanktionAlt model (Vergütung reduction, not penalty payment):

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 EEG 2023: Pflichtzahlung from operator to NB — Vergütung continues, penalty is netted (§52 Abs. 6 EEG 2023):

SanktionsTyp	Nr.	Rate	Retroactively reducible?
FernsteuerbarkeitmFehlend	Nr. 1	€10/kW/month	Yes → €2 on fulfillment
SpeicherAnforderungNichtErfuellt	Nr. 2	€10/kW/month	No
IMssAnforderungNichtErfuellt	Nr. 3	€10/kW/month	Yes → €2 on fulfillment
DirektvermarktungspflichtVerletzt	Nr. 4	€10/kW/month	Yes → €2 on fulfillment
MastrNichtRegistriert	Nr. 11	€10/kW/month	Yes → €2 on fulfillment
InbetriebnahmeVorgabeVerletzt	Nr. 9a	€2/kW always	N/A (§52 Abs. 3 Nr. 2)
VolleinspeisungspflichtVerletzt	Nr. 10	€2/kW always	N/A (§52 Abs. 3 Nr. 2)

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

§52 violation start tracking

einsd automatically tracks violation start dates:

• On plant registration (POST /api/v1/anlagen): when mastr_registriert = false, sets mastr_violation_start = CURRENT_DATE if not already set.
• On MaStR confirmation (POST /api/v1/anlagen/{tr_id}/mastr-registrierung): clears mastr_violation_start = NULL, stopping penalty accrual.
• In monthly settlement: cumulative monate_des_verstosses is computed from the start date → correct §52 Abs. 2 amount is charged from the first month of violation.

---

§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": "MARKET_PREMIUM",
  "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 — Regional and Auction Reductions

§53b — Regionale Grünstromkennzeichnung

BNetzA-certified grid areas receive a per-ct/kWh reduction on Einspeisevergütung. Applied automatically when the plant's grid_area matches a certified area in sect53b_reductions.

Register the plant's Netzgebiet when creating it:

{ ..., "grid_area": "DE-TN-001" }

The reduction is queried from sect53b_reductions during each settlement and passed as sect53b_regional_reduction_ct to eeg-billing.

§54 — Ausschreibungsreduzierung

BNetzA may reduce the awarded AW for Ausschreibungsanlagen. sect54_reductions stores per-plant BNetzA deductions. Applied automatically during settlement: effective_aw = direktverm_aw_ct − deduction_ct (floor 0).

Manage via direct DB insert (no API endpoint; BNetzA-driven):

INSERT INTO sect54_reductions (tr_id, tenant, deduction_ct_kwh, bnetza_ref, effective_from)
VALUES ('DE_TR_...', 'your-tenant', 0.50, 'BNetzA-54-2026-WIND-001', '2026-01-01');

---

§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
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).

---

§ 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. Snapshots the original receipt to settlement_receipt_history (immutable, § 147 AO / GoBD)
2. Re-runs settlement with corrected inputs
3. 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 (§22 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 §22 EEG provisions. This endpoint models the most common full-repowering case. Always confirm the specific plant scenario with the applicable §22 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)

Co-located same-technology plants commissioned within 12 calendar months can be merged:

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

{ "parent_tr_id": "DE_PARENT_MAIN" }

Child → abgemeldet. Parent foerderendedatum unchanged. Update verguetungssatz_ct if the combined capacity crosses a rate band boundary.

---

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
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	Repowering §22 EEG
POST	/api/v1/anlagen/{tr_id}/zusammenlegen	Zusammenlegung §24 EEG
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
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)
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
tarifbd_url	no	—	tarifbd URL for EPEX sync
alert_interval_secs	no	21600	Förderendedatum alert interval (6h)
mcp_api_key	no	—	Bearer token for /mcp (open = dev 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	FEED_IN_TARIFF, MARKET_PREMIUM, …
direktverm_aw_ct	NUMERIC?	Statutory AW in ct/kWh (before Managementprämie)
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)
bank_iban	TEXT?	IBAN for EEG Vergütung payment (SEPA CT, NB→Betreiber)
ust_status	TEXT	Operator's declared VAT status — KLEINUNTERNEHMER (§19, E/0 %) or REGELBESTEUERUNG (§12 Abs. 1, S/19 %); drives the Gutschrift USt
status	TEXT	angemeldet, aktiv, foerderung_beendet, repowered, abgemeldet
inbetriebnahme_typ	TEXT?	ERSTINBETRIEBNAHME, REPOWERING, ERWEITERUNG, …
solar_bauform	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_pflicht	BOOL	true for plants > 100 kW (auto-set on creation)
direktvermarktung_perioden	JSONB?	History of Direktvermarktung engagements
capacity_blocks	JSONB?	§24 Erweiterung blocks
metering_mode	TEXT?	SLP / RLM / IMSYS metering classification
metering_mode	TEXT?	SLP, RLM, IMSYS
sect52_netting_enabled	BOOL	§52 Abs. 6 netting (default true)
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)
grid_area	TEXT?	Netzgebiet code for §53b regional reduction lookup (e.g. "DE-TN-001")
award_expired	BOOL	§35a EEG 2023: Zuschlag expired/revoked → FoerderungBeendet
zuschlag_erloeschen_datum	DATE?	§35a: date when BNetzA Zuschlag automatically expires
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
verlaengerungsanspruch_qh_gesamt	BIGINT	§51a: cumulative quarter-hours of Förderzeitraum extension

Views: eeg_anlagen_mastr_ausstehend · eeg_anlagen_fernsteuerbarkeit_ausstehend · eeg_anlagen_direktverm_pflicht

settlement_receipts

Immutable active receipt per billing period. Unique per (tr_id, tenant, billing_year, billing_month) — corrections overwrite the active row, with the original preserved in settlement_receipt_history.

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. One row per correction — captures the full original receipt as JSONB before any correction upsert overwrites it. Query this table to reconstruct the billing history for any plant and period.

settlement_state_transitions

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

sect54_reductions

§54 EEG 2023 Ausschreibungsreduzierung notices per plant (from BNetzA).

sect53b_reductions

§53b EEG 2023 regional Grünstromkennzeichnung reductions per grid area.

eeg_verguetungssaetze

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

epex_monthly_prices

EPEX Spot monthly averages. Required for MARKET_PREMIUM and POST_EEG.

---

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 eeg_anlagen 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 eeg_anlagen.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.

{
  "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":         "51238696780",
    "billing_year":    2026,
    "billing_month":   7,
    "settlement_model": "FEED_IN_TARIFF",
    "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 + X-Mako-Signature HMAC.

---

MCP Server

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

18 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_tool · get_settlement_state_history · explain_settlement

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. 2 Nr. 4 violation candidates.
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.

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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