mirror of
https://github.com/Legolas-2025/EPrices.git
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Amir
6f3ba88394
Introduced support for negative provider fees with a new secret key and updated price calculation methods for both positive and negative prices.
73 lines
3.3 KiB
Markdown
73 lines
3.3 KiB
Markdown
# EPrices – Version History
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## v1.1 — 2026-04-06
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### Negative price provider fee
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Added separate provider fee support for negative spot prices via a new
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`eprices_neg_prov_fee` secret key. Positive and negative market prices
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now use independent fee multipliers, correctly modelling contracts where
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the provider's fee structure differs between the two cases.
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Price calculation:
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- Positive: `(raw / 1000) × (1 + prov_fee) × (1 + vat_rate)`
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- Negative: `(raw / 1000) × (1 - neg_prov_fee) × (1 + vat_rate)`
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VAT is applied to both, consistent with net billing where VAT is calculated
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on the monthly net sum (linear equivalence applies).
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See `CHANGELOG.md` for full implementation details.
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---
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## v1.0 — 2026-04-05
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First public release.
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### What EPrices is
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EPrices is an ESPHome firmware for ESP32 that fetches day-ahead electricity
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spot prices from the public Energy-Charts API and exposes them as Home Assistant
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sensors. No API token, no cloud subscription, no external automations required
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for core functionality — just an ESP32, ESPHome, and your WiFi network.
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Prices are fetched for today and tomorrow in 15-minute resolution, converted
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from raw €/MWh to €/kWh with your provider fee and VAT applied, and stored
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persistently in ESP32 NVS flash so they survive reboots without re-fetching.
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### Core features
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- 15-minute and hourly resolution price arrays exposed as JSON text sensors
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- Current, next, average, highest and lowest price sensors for both today and tomorrow
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- Tomorrow live sensors evaluate at `now + 86400s` — showing tomorrow at the same local time
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- NVS persistence — prices survive reboots without re-fetching
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- Midnight bridge — tomorrow's data automatically promoted to today at 00:00
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- Auto-retry logic — up to 8 HTTP fetch attempts for both today and tomorrow
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- DST-safe — UNIX timestamps and binary search throughout, no hour-slot arithmetic
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- Staleness detection — `Today Current Price Status` shows `Stale` if stored date mismatches today
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- Full diagnostic sensor suite — NVS status, fetch attempts, API fetch times, data loaded
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times, WiFi signal, human-readable uptime
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- Supports any Energy-Charts bidding zone (SI, DE-LU, AT, FR, HR, HU and more)
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- Provider fee and VAT rate configurable via `secrets.yaml` — no code changes needed
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### Sensor highlights
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- **Today/Tomorrow JSON Hourly Prices EUR⁄kWh** — 24-value JSON arrays
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- **Today/Tomorrow JSON 15-Min Prices EUR⁄kWh (P1/P2/P3)** — three 32-value JSON arrays
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covering 00:00-07:45, 08:00-15:45 and 16:00-23:45
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- **Today/Tomorrow Data Loaded Time** — stamped on both NVS load and HTTP fetch
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- **Today/Tomorrow Last API Fetch Time** — stamped on HTTP fetch only; `Never` if NVS only
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- **Today/Tomorrow API Fetch Attempts** — HTTP-only counter, resets at midnight
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- **Uptime** — human-readable: `45 s` → `5 min` → `3 h 22 min` → `12 d 4 h` → `4 months 12 d`
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### Files
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| File | Purpose |
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|---|---|
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| `eprices.yaml` | Main ESPHome configuration |
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| `eprices_nvs.h` | NVS helper — save/load price arrays to ESP32 flash |
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| `secrets.yaml` | Local secrets — not committed to git |
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| `CHANGELOG.md` | Full sensor and entity ID reference for v1.0 |
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| `README.md` | Installation guide and full sensor reference |
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| `ENTSO-E-PRICES-MIGRATION.md` | Optional — migration guide from the predecessor project |
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