These charts show that coal fired plants will be used to fill the night time electicity demand. (pbs.org)
Fuel goes in the front end, electicity comes out the back end, and the used fuel is stored on site ready to be recycled. (realclimate.org)
The reason for the second question is because cheap electricity will much more quickly displace fossil fuels, not just for electicity generation but also for heat and transport. (bravenewclimate.com)