I have created an Apple Watch app that provides a PVOutput.org complication for watch faces.
The complication shows the day’s energy generation and most recent power generation, either as W or as a percentage of system capacity, depending on the complication you use.
Complications only get updated 4 times per hour, so the figure shown in the complication can be up to 15 minutes or so behind the most recent update. Tapping the complication will give you the most recent update to your system and also refresh the complication.
It is a stand-alone watch app, so you will need watchOS 6.0.
The app is available on the App Store