The maintenance cost on them alone will equal the cost of producing coal fired electricity. They have to be cleaned weekly and the cells become weaker as they break down over a relatively short period of time. 10 years would be an exceptional life span, if they are used continuously. And then there is the added cost of incorporating such an unstable and unreliable form of power into the grid.
The cost will be phenomenal and electricity bills will more than triple to make up the gross inefficiency of these systems.