How each monthly payment relates to your actual electricity usage will vary depending on the time of the year.
For example, in the summer you will use relatively small amounts of electricity so your payments will be higher than your actual usage. Since you’re paying more than what you’re using, you build up credit on your account.
On the other hand, during the winter you will use relatively large amounts of electricity so your payments will be lower than your actual usage. During these months, your account will draw on the credit you built up during the summer.
On the back of your 3-monthly statement there is a section called ‘Electricity Usage Details’ which details all your meter readings during this period. If you submit regular meter readings you can track your whole usage history online through My Airtricity.