.
,
Diesel plants start on batteries.
Sorry.
I am sure they have huge generators on trucks or something. I am sure someone else will pop along with a better answer.
I am sure I didn’t mean to use ‘I am sure’ twice like that.
The power to bring up the nuclear power plant on U.S. submarines can be supplied by the on-board diesel generator. The diesel generator is started with compressed air. Civilian nuclear power plants are required to have backup diesel generators as well to power the protective equipment. I’m fairly sure they can be used to start up the plant as well.
However, as others have posted in related current threads, civilian nuclear power plants are required to have off-site power available to power protective and cooling equipment. The on-site diesel generators are intended to provide backup power in the event that off-site power is lost.
And now that I think about it, I seem to recall this being the case when I was training on a land-based nuclear power plant some 11 years ago.
Only very small diesels. Any diesels large enough to be generating stations are started with compressed air.
Today a number of fossil plants have enough emergency power to start the plants back up. However, this was not the case for older plants. As I recall, in the big East Coast outage of 25 years ago, some plants were restarted by rigging power lines from ships.
I already posted at length about this in the other thread (which few read, apparently…I must be on everyone’s Ignore lists or something the last few days) but somewhere, I do have a JPG of a battleship in New York harbour, being used to start a plant on the shore. Using the ultimate in “jumper cables”, which you can see in the photo. Sadly, I have about…20 GB of power plant pics, and it’s going to be hard to find.
Anthracite: Is there any way I could see some of these pictures in your collection? Perhaps we can arrange something off list?
My best artistic ones are in the private gallery for my Board Members on my server (except for a batch I haven’t uploaded yet). Much of the rest are work-related, and I can’t show those to other people (pictures of plant equipment, monitors, construction, unsafe work practices, etc.) In any event, the battleship pic seems to be gone. 
A lot of power plants do it by degrees: A small diesel generator is fired up by batteries, it drives a few small electric pumps, (feedwater, fuel oil, compressors for control air), then you light off a boiler, and feed steam to larger, turbine driven pumps and light off the rest of the plant. Then you bring the generators on line.
This is obviously for oil fired plants. Gas fired plants you wouldn’t need the fuel pump. Hydro electric you can restart almost instantly. Nukes take the longest to restart, as the cooling system has to be up and running before the generation side can be lit off.
In reply to the OP:
You get a bike, a fly wheel and Lance Armstrong…
Gimme a cite for that, sport.
Large ship’s diesels are definitely started with compressed air. You’d need a hell of an electric starter motor.
I still want a cite, sailor.
Both references to compressed air starting have been anecdotal, and ship-board.
I do not know if electric power plants would use large diesels. I doubt it and I am inclined to think they would use turbines instead. Anthracite would know this. BUT if any electric power plants are or were using really large diesels, comparable to those used on ships, I have no doubt in my mind they were started using compressed air and not with an electric starter motor. A small diesel can be cranked up to speed in a fraction of a second with a powerful electric starter motor. That is just not feasible with a huge diesel. Compressed air allows a much more gradual speed-up. I know well the intricacies of large marine diesels. They were started rotating with compressed air. When you had enough speed you would start injecting fuel in one cylinder and gradually start the rest. The propeller shaft was solid with the diesel’s crankshaft so the only way to reverse the prop was to reverse the engine. Stopping it and reversing it was also done with compressed air. It just would not be possible to use an electric motor for this whereas compressed air lends itself perfectly for this task. It would take several minutes to stop the engine and start it rotating in opposite direction. Note that these diesels rotate very slowly, in the range of 60 - 120 RPM, but the moving parts weigh tons.
If a diesel like that was ever used in a power plant it would be started with compressed air because it’s the only sensible way to do it. Now, if you claim huge diesels are started with an electric starter motor, that is an extraordinary claim and it is up to you to support it, not for me to debunk it. I would like to see the electric starter motor which could start such a diesel.
I know of no compressed air systems to start diesels at land-bound power plants. However, this should not be taken to mean it’s not used - I’ve just not encountered it, and as far as the practices of “Startup” of the “Startup” systems, I freely admit to being a little in the dark. I don’t know if the fact that land-bound plants can go thousands of hours between starts means that such a system might not be practical. 