Stephen A. Lawrence wrote:
The average nuclear plant is about 980 MW I think, and in 1999 the capacity factor was 88.5%, which is lower than I expected. In other words "actual" size is around 870 MW.
I don't understand this. I'll expose some ignorance; perhaps someone can address it:
Is 980MW the "shaft power" -- the available mechanical power which can spin generators?
No. Sorry, I should have written: 980 MWe (megawatts electric). As I recall, that is the average capacity of U.S. nuclear plants. I multiply that by the capacity factor, 88.5%, to conclude that a 980 MWe nuclear plant produces about 870 MWe on average.
The capacity factor is how much the generators are actually used on average during the course of the year. 88.5% is the percent of maximum rated output. Actually, most nuclear plants are either running at 95 to 100% of capacity, or they are turned off for maintenance. I think they are usually off for about a week per year, while they are being refueled or repaired. Once they are turned on, they are seldom run below full capacity, even at night. They are "baseline" generators, because the fuel is cheap but the equipment is expensive.
- Jed
