I did last grow with a mixture of 2700K & 5000K, had a 300watt cfl, a 200, and 9, 100s. I think the lumins added up to around 20,000, can't find my notes. They did pretty good. Have a HPS/MH now and a lot better and wish I just had purchased to start with as I spent alot on all the cfl's and fixtures to burn them in and my HPS/MH 600watt is alot better and easier to use. Don't think the electric should be much more than when using cfls from what I've read. Had to keep moving those cfls and when the plants got bigger they sometimes burned leaves before I could move. Had to keep within a few inches of plant and that was a pain.
If anyone knows what the 600watt using HPS runs in a month I would love to know. Best I could figure out in a couple of months, the cfls cost about $30 a month.
Did have use for all those cfls. All over my house to save on electric. Except 300 & 200. Just keep them in case I ever need I guess.
600watt HPS is the way to go. $250. cost