Beautiful thing about percentages...

It’s the same thing. Say you have a bill of 120€/year. On average that comes to 10€/month (120€ divided by 12 months). If you have save 10% a month you save 1€, which after 12 months becomes a saving of 12€. Now do that yearly: 10% of 120€ is… 12€.

I pay 100 Euros per month energy bill and save 10% of it so 10 Euros per month or 120 Euros per year.

Secondly unfortunately

Are you paying for electricity and transfer on a separate schedule or something?