a6d3c3e1c2
Le canal testing sert powersync-plugin-openmeteo 1.15.2+etm1 (publié le 2026-09-08 à 09:49, avant le Contrat A). Cette version envoie les coordonnées du site sans arrondi ; l'arrondi à deux décimales n'existe que depuis etm2, et etm2 à etm16 ne sont dans aucun canal. La fiche OpenMeteo, la page Prévision PV et la FAQ (trois langues) disaient « arrondies à environ 1 km » sans condition. Elles le qualifient maintenant par version, et la fiche porte un avertissement en tête : version décrite à partir de 1.15.2+etm2. PORTING_STATUS reste `testing` : c'est exact. TODO : retirer ces avertissements quand etm16 ou suivant entre dans testing. Vérifié comme en CI : génération, --check et mkdocs build --strict passent. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
104 lines
4.8 KiB
Markdown
104 lines
4.8 KiB
Markdown
# PV production forecast
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<span class="badge testing">BETA</span> <span class="badge community">COMMUNITY</span>
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The box forecasts the production of your panels, hour by hour, until the end of the
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next day, and shows it in the app next to the measured production. It is a feature of
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the **Community** edition (GPL-3.0): it relies on the energy engine and the
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[OpenMeteo](../appareils/tarifs/openmeteo.md) plugin, with no ETM service involved.
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!!! info "Beta"
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Delivered and running on our test installation, it is not yet published in a
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channel of the APT repository.
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## What you see in the app
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- **The expected production curve**, hour by hour until the end of the next day,
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overlaid on the measured production.
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- **A weather range** around this curve (see below).
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- **Hour-by-hour weather** on the "Journée" card: an icon (sun, clouds, rain…), day or
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night, and the temperature.
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## How the forecast is computed
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For each declared PV plane — tilt, orientation, peak power (kWp) and system efficiency
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—, the box converts the irradiance forecast by Open-Meteo into power. It then adds up
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all the planes of the site.
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Two corrections apply, both **deterministic**: public physical models, parameterised
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from datasheets, with no learning at all.
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- **Temperature correction**: a hot module produces less. The box estimates this from
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the forecast temperature, the NOCT and the temperature coefficient of the modules.
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- **Inverter ceiling**: the sum of the planes never exceeds the inverter's maximum AC
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power, if it has been entered.
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The forecast is recomputed whenever the weather models publish a new run — at most once
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an hour.
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### A forecast, and an optimistic ceiling
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What the box shows is a **forecast**, not a measurement. It is also an **optimistic
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ceiling**: shading (trees, chimney, neighbouring buildings) and soiled panels are not
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modelled. Actual production below the curve is therefore normal and does not indicate a
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fault.
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### An hour without data is a gap, never a zero
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If an hour is missing (internet down, weather service unavailable), the curve breaks.
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The box never writes "0" instead: a zero would read as "no sun expected".
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## The weather range
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Around the curve, the app draws a band:
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**forecast × (1 ± spread of the day's models)**. The spread measures how far several
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weather models disagree about the day.
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This band qualifies **the weather**, and only the weather. It says nothing about the
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accuracy of the production forecast: shading and soiling are not in it. On a clear,
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stable day it is narrow, precisely when the error from those factors is largest. It is
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therefore neither an "expected error" nor a "confidence interval".
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## Commissioning
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1. Install the OpenMeteo plugin and create the **site** and its **PV planes** — see
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[OpenMeteo](../appareils/tarifs/openmeteo.md).
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2. **Designate the forecast site** in the app. Until one is designated, the forecast
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card shows a notice and offers the available sites. All planes of the designated
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site are added up.
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3. Optional: enter the **inverter ceiling** (maximum AC power, in W). Without it, no
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ceiling is applied.
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## What the forecast does not do
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This is the central rule of the Community edition: **without an optimiser, control is
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rule-based** (solar surplus, load shedding, priorities). The PV forecast, the
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[entered tariff](../tarifs.md) and the baseload are **displayed** and **recorded
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locally**, but never used to decide. An automated test checks this: the engine makes
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the same decisions with and without forecast, tariff and consumption profile.
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The local record is used to measure forecast accuracy over time. Validation on a real
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installation is under way; no accuracy figure is published before it is complete.
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## Baseload forecast <span class="badge nightly">COMING</span>
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The box will compute a household consumption profile, excluding controlled loads, from
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its own measurements: a median for each hour of the day, separately for working days
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and weekends. A profile needs at least **7 days** of measurements. Until then nothing
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is shown: an absence, never a zero.
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## Your data
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Only the OpenMeteo plugin connects to the internet. It sends only the **site's
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coordinates** (rounded to about 1 km in the plugin versions that carry this feature; version `1.15.2+etm1` in the testing channel sends them unrounded), its **altitude** if entered, and the
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**orientation of the panels** (tilt, azimuth). Measurements, recorded forecasts, the
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tariff and consumption stay on the box. Remote access is disabled by default: it opens
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only if you enable it yourself in the app.
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## What about an optimiser?
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The architecture provides an **open, documented interface** to an external optimiser,
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which could use these forecasts to plan. Optimisation would run at your place, on the
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box or on a machine in your local network. This connection is under development; the
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Community edition works entirely without it.
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