Custom Forecast Solar

Home Assistant HACS custom integration that maps custom forecast sensors to a unified solar forecast format compatible with the Energy Dashboard.

Features

• Config Flow in the UI
• Configurable days: today up to +7 (only enabled days are used)
• Per-day selectable source format:
  • ml (Solar-Forecast-ML style, attributes.hours)
  • solcast (Solcast style, attributes.detailedForecast)
• Optional fallback integration for historical gaps (for example solcast_solar)
• Energy-compatible sensors (device_class: energy, state_class: total, unit: kWh)
• Registers as a solar forecast provider for the Energy Dashboard

Installation (HACS)

1. Add this repository to HACS as a custom repository (type Integration).
2. Install the integration.
3. Restart Home Assistant.
4. Add the Custom Forecast Solar integration via the UI.

Configuration

The Config Flow exposes three fields per day index 0..7:

• enabled — enable this day's mapping
• entity — source sensor entity
• format — ml or solcast

Optional fallback settings:

• fallback_enabled — enables backfilling of missing past slots
• fallback_domain — integration domain (for example solcast_solar)
• fallback_config_entry_id — selected config entry from that integration

Example:

• Day 0: sensor.remoteprognose_heute, format ml
• Day 1: sensor.remoteprognose_morgen, format ml
• Day 5: sensor.solcast_pv_forecast_forecast_day_5, format solcast

Energy Dashboard integration

After configuring the integration:

1. Open Settings → Energy
2. Under Solar, click Add solar generation or consumption
3. Select the custom_forecast_solar integration
4. The integration should automatically provide the configured forecasts

The integration registers itself as a solar forecast provider for all configured days.

If enabled, missing past wh_hours slots are backfilled from the configured fallback integration. Current and future slots from this integration are kept as primary.

Note: The Energy Dashboard will only display forecasts when at least day 0 (today) is configured.

Supported source formats

ml format

• attributes.hours: mapping of "HH:00" -> kWh
• optional daily value may appear in state or attributes.raw

solcast format

• preferred: attributes.detailedForecast entries containing:
  • period_start
  • pv_estimate
  • optional pv_estimate10, pv_estimate90
• fallback: attributes.estimate or state

Output

For each enabled day the integration creates an energy sensor with:

• daily value in kWh
• detailedForecast (ISO-formatted timestamps in half-hour intervals)
• detailedHourly (hourly aggregation)

These sensors are created under sensor.custom_forecast_solar_forecast_* in Home Assistant.

Debugging

If the Energy Dashboard does not display the forecast:

1. Check logs: set logger for custom_components.custom_forecast_solar
2. Call the debug service: custom_forecast_solar.get_forecast_debug
3. Validate entities: ensure sensor.custom_forecast_solar_forecast_today exists
4. Validate sources: make sure configured source sensors exist and expose valid data

Notes

• If a source sensor is missing or provides invalid data, the coordinator update will be marked as failed.
• Changing options will automatically reload the integration.
• The integration provides forecast data to the Energy Dashboard in Wh (watt-hours) per half-hour slot.