You lose 10% of the power output of the solar panel. i.e. solar panels utilize 20% of the solar energy they receive but within hours that drops to 18% for the

You lose 10% of the power output of the solar panel. i.e. solar panels utilize 20% of the solar energy they receive but within hours that drops to 18% for the life of the panel. So yes, it's a 2% absolute drop relative to the solar energy the panel receives, but it's 10% of what the panel was ever able to produce.