I visited a coal power plant on the weekend, and was quite impressed by the scale and enormity of the operation. 10 storey high boilers suspended from the ceiling, Turbines and generators the size of two semi trailers, etc. (I highly recommend it if you can spare the time) Unfortunately our tour guide was a bitter, jaded security guard and was unable/unwilling to answer most of my questions. The power plant sported pretty impressive figures for a non-supercritical coal fired plant. Each turbine consumes about 80kg/s of coal, producing 560kg/s of steam to generate 660Mw. Given the scale and size of the installation, I'm wondering why they stop at 660Mw. Why not a gigawatt turbine? Why not two gigawatts? I can't really think of any good logistical reason for this. Is it simply economics? Maintenance logistics? or is there some good engineering reason why powerplants aren't bigger than they are.