As your source shows, solar can be very cheap (utility grade solar providing power when it is sunny) to the most expensive form of electrical power in the world

As your source shows, solar can be very cheap (utility grade solar providing power when it is sunny) to the most expensive form of electrical power in the world (residential solar on rooftops). You can also see that if you also want power when it isn't sunny (or windy if using windmills) you need to add in the cost of utility grade storage which noticeably increases the costs.