Does the customer pay for energy produced or energy used? What if the panels produce more than the customer can use?

There may be periods where production exceeds demand and energy is delivered back into the utility grid and generating a credit with the utility. We size the system so that it closely matches actual demand. However, if you are a school for instance, you will generate more energy than you need during the summer months at a high rate, but use more from the grid in the winter when you are paying lower rates. This is one of the great advantages of solar PV – sell energy when rates are high; buy it when rates are low.