What do you mean how it will affect your bill?
THis is more specific to a commercial bill, but there are some components which are helped by solar and some which are not. Many (most?) solar places just divide the total bill by an amount of kWh and use that to calculate that if the system will generate an amount of kWh then it will save you that amount. This is simply untrue. Some components will remain the same as they were before solar was installed.
This can bring the price per kWh after solar higher than it had been prior. A client of mine bought a building which had a solar contract where they were required to pay the owner of the solar system by calculating the amount of his bill and dividing it by kWh then paying that amount for the solar generation while receiving rent for the roof space. This ended up making him pay for some components multiple times over when the generation was high.