For some automations, it will be useful to know how much solar power you might get tomorrow. To integrate it in Home Assistant, you can do the following.

Go to Settings on the left panel.

Select Devices & Services

Click on ADD INTEGRATION in the lower right.

Search for Forecast.Solar and click on it.

Enter your location, direction of the solar panels, the slope of the roof, and the peak watts.

(For the total watt peak power, it is easy to make the mistake of misreading it and entering the KW value of your panels, as I have in the screenshot. This is corrected later on in this page).

Click SUBMIT when finished entering the details.

Select the area and click Finish.

You can check that the new entities show up.

Now we need to update the inverter size.

Click Settings.

Devices & Services.

Select Forecast Solar.

Select Configure.

Add in the inverter size in watts and click Submit.

Congratulations. You have now added a solar power forecast to your Home Assistant. Next up is to configure Zappi Integration