Every year, the power company increases its cost of electricity. $100 can easily inflate to $450-$500 in 20-25 years and there is nothing that you can do about it. Every year, you pay more and will continue to pay until the day you die.
Solar is a flat fixed cost that never goes up. In fact, once you’re done paying for it, you’ll never see another bill from the power company for up to 30 years. Think of it as owning vs. renting.