And requires 5040 days to provide $4032.00 of electrical power. Or 13.8 years.

Now factor-in interest rates and the cost of your $4032 in capital. (Plus installation costs and , maintenance - OPEX), and "opportunity cost" - what ELSE could you have done with a lazy $4000?

It is generally true that any item with a notional interest-free "payback period" exceeding 10 years is actually a loss-maker after interest costs. You would be better-off putting your money in the bank and paying your future bills from the interest. (But don't put the money in the stock market! or in dodgy debt finance!)

It is a common factor of "green" and other philosophies that they neglect interest charges when telling us that "Item X will save you money and is good for the planet"