Web App ideas - Lemmy.World

I have some spare time and I was thinking about how I can contribute to our economy using my programming skills. Do you have any applications ideas? I was thinking about energy management app for solar and battery storage. I live in Poland and I just installed solar panels with energy storage system. But default settings are very limited. I want to predict my future production, consumption, when to charge battery storage, when to discharge… That the first idea. Another one is advanced calculator which show how profitable PV system can be. I know there is official app from eu parliament, but it has very limited settings…