On grid solar power can be very profitable in Indonesia. However, it is not so easy to calculate how many solar panels you should buy. This depends on three factors: 1. how much sunshine there is at your home, 2. how high your monthly electricity bill is, 3. the power of your electricity connection.
Based on these factors, this application calculates how many panels you should install. It will also estimate the return on investment, using up to date PLN tariffs.