Forecast.Solar

The Forecast.Solar integrationIntegrations connect and integrate Home Assistant with your devices, services, and more. [Learn more] estimates how much energy your solar panels will produce, using the Forecast.Solar service. The forecast combines the location, orientation, and size of your panels with historic averages and weather data, so you can plan ahead and use your own solar energy as efficiently as possible.

For example, you could use the forecast to decide whether you will produce enough solar energy in the next hour to run the washing machine, or whether to charge your electric vehicle from the sun tomorrow instead of from the grid overnight.

Prerequisites

Forecast.Solar uses data from the EU Photovoltaic Geographical Information System, which covers almost the entire world. Your panels need to be in a location that this tool covers.

To create a forecast, the integration needs a few details about your solar setup:

• Location: The latitude and longitude of your panels. By default, this is taken from the home location set in your Home Assistant settings.
• Declination: The tilt of your panels in degrees. A value of 0 means the panels lie flat, facing straight up, and 90 means they stand fully upright.
• Azimuth: The compass direction the panels face, on a 360 degree scale. 0 is north, 90 is east, 180 is south, and 270 is west.
• Total Watt peak power: The combined maximum power of all your panels, in Watt peak. Add up the peak power of every panel in the group to get this value.

Configuration

To add the Forecast.Solar service to your Home Assistant instance, use this My button:

Configuration options

After setup, you can fine-tune the forecast. Go to Settings > Devices & services, select the Forecast.Solar integration, and then select the cogwheel (Configure).

Adding multiple planes

A plane is a group of panels that share the same orientation. If your setup has panels facing different directions, such as an east-west roof, you can add each orientation as a separate plane within the same integration.

Adding more than one plane requires a paid Forecast.Solar account. See Using a Forecast.Solar account. You can configure up to four planes, and the integration combines their data into a single set of sensors, taking your inverter size into account if you set one.

To add a plane:

1. Go to Settings > Devices & services and select Forecast.Solar.
2. Select Add plane.

Using a Forecast.Solar account

You can use the public Forecast.Solar service for free, but the data has a lower resolution, the forecast updates less often, and you can configure only a single plane.

If you would like more frequent updates or want to add multiple planes, you can sign up for one of their plans. The Personal Plus tier and above let you configure up to four planes.

To use your account, add the API key in the integration’s configuration options, as described under Configuration options.

Tweaking the estimations

A forecast will never perfectly match what your panels produce, because it is based on weather and historical data rather than the power you actually generate. Even so, you can make it more accurate for your situation in a few ways:

• Fine-tune the azimuth and declination if the real orientation of your panels differs slightly from what you first entered. To change these, reconfigure the plane from the integration page.
• Set a damping factor for the morning and the evening if your panels catch some shade early or late in the day. Damping lowers the forecast at those times, making it less optimistic and closer to your reality.
• Set the inverter size if your inverter can deliver less power than your panels can produce together, so the forecast does not exceed what your inverter can handle.

You can change the damping factors and inverter size at any time under Configuration options. For more background on damping, see the Forecast.Solar damping documentation.

Supported functionality

The integration provides sensors that you can show on a dashboard or use in automations.

The following sensors are enabled by default:

• Estimated energy production - today: Total estimated production for today, in kWh.
• Estimated energy production - remaining today: Estimated production still to come today, in kWh.
• Estimated energy production - tomorrow: Total estimated production for tomorrow, in kWh.
• Estimated energy production - this hour: Estimated production for the current hour, in kWh.
• Estimated energy production - next hour: Estimated production for the next hour, in kWh.
• Estimated power production - now: Estimated power being produced right now, in Watt.
• Highest power peak time - today: The time of the highest expected power peak today.
• Highest power peak time - tomorrow: The time of the highest expected power peak tomorrow.

The following sensors are disabled by default. Enable them in the user interface if you want to use them:

• Estimated power production - in 1 hour: Estimated power production one hour from now, in Watt.
• Estimated power production - in 12 hours: Estimated power production twelve hours from now, in Watt.
• Estimated power production - in 24 hours: Estimated power production twenty-four hours from now, in Watt.

Using the forecast in the Energy dashboard

If you track your solar panels in the Energy dashboard, you can pair them with Forecast.Solar. The solar production graph then shows the forecasted production alongside what your panels actually generate, so you can see at a glance whether the day is living up to its prediction.

To add the forecast:

1. Go to Settings > Dashboards > Energy.
2. Under Solar panels, select your solar production entry. If you have not set one up yet, see integrating your solar panels first.
3. Turn on the solar production forecast option and select Forecast.Solar.
4. Save your changes.

The Energy dashboard now overlays the expected production on your solar graph.

Data updates

How often the forecast updatesData polling is the process of querying a device or service at regular intervals to check for updates or retrieve data. By defining a custom polling interval, you can control how frequently your system checks for new data, which can help optimize performance and reduce unnecessary network traffic. [Learn more] depends on your Forecast.Solar account:

• Free accounts update every hour.
• Accounts with an API key update every 30 minutes.

The forecast always remains an estimate based on weather and historical data, not a measurement of the power your panels actually produce.

Known limitations

• The free service offers a lower data resolution, updates less often, and supports only a single plane. More frequent updates and multiple planes require a paid Forecast.Solar account.
• Your panel location must be covered by the EU Photovoltaic Geographical Information System.

Removing the integration

This integration follows standard integration removal. No extra steps are required.

To remove an integration instance from Home Assistant

1. Go to Settings > Devices & services and select the integration card.
2. From the list of devices, select the integration instance you want to remove.
3. Next to the entry, select the three dots menu. Then, select Delete.