Your electric utility encourages you to use less electricity and save money because it prevents overloads of the electrical grid during peak demand times like when electric space heaters are running or air conditioners are running.
The reduced strain on the electric grid by you lowering your electric usage and saving money also prevents the possibility of expensive equipment failures that are costly to repair and replace parts like transformers and other equipment should they fail.
Encouraging you to lower your electricity usage and save money on your electric bill also helps the electric utility avoid the massive cost of having to build or fire up extra power plants.
And lowering your overall electric demand, helps the electric utility to meet strict environmental regulations and ensures system reliability for everyone.
Also when electricity demand increases, electric utilities may also need to purchase additional power from other power plants other than their own power plant to meet demand.
This is true, even when your electricity owns their own power plants and mainly uses their own power plants to generate your electricity.
But if the demand increases, and they don't have a peaking plant to meet the demand themselves, the electric utility will purchase additional capacity and electricity from another power plant.
So while the electric utility wants to make money, they also want to avoid costly repairs and due to the electric utility having several thousands of customers depending on your electric utility, the electric utility already makes plenty of money even when you use less electricity.
Just off of the customer charges alone they generate substantial revenue.
But they also generate money of the electric usage but when you use too much and put strain on the grid, it results in costly equipment failures in some cases and can lead to power outages and if the equipment fails, it costs the utility money.
Just like when storms occur and equipment gets damage and power lines go down, that costs the utility money as well.