3 ms·
> However, large steam turbines simply take a lot of energy to warm up to operating temperature. Boilers, not turbines. The boilers at a coal plant are giganti
by timr 4y ago
> However, large steam turbines simply take a lot of energy to warm up to operating temperature.
Boilers, not turbines. The boilers at a coal plant are gigantic -- 5+ story hunks of metal the size of city buildings. They don't turn on/off on demand. The whole system is complex, of course, but the boilers are giant boxes of fireball that flash-vaporize water using pulverized coal at ~500C and 200+ bar of pressure [1].
My father was a control systems engineer for coal plants (and later, gas) for a major utility. When I was a child, he'd be away for weeks at a time when plants were spun up or down for maintenance.
One of the more memorable events in my life was when I was allowed to take a tour of a big coal plant when it was down for maintenance. Those boilers were terrifying, even when "off". The gates of hell.
[1] https://www.sciencedirect.com/topics/engineering/pulverized-coal-boiler https://www.sciencedirect.com/topics/engineering/pulverized-...
- Retric 4y agoI was referring to a nuance that’s easy to overlook. As you say the coal power plant needs to heat up a boiler to operating temperatures before it’s turbine can generate power. Yet, that’s still not enough for maximum efficiency. Cold pipes and turbine blades steal energy from the steam. Similarly the boiler is less efficient when fed cold water vs hot water from the condenser. Thus the startup process is more involved than just how long it takes to start generating power. The most efficient coal power plants are actually double-reheat which takes even long to get up to optimal conditions. https://www.sciencedirect.com/science/article/abs/pii/S0360544220307015 https://www.sciencedirect.com/science/article/abs/pii/S03605...
- timr 4y agoYes, definitely. Not disagreeing with you, just adding color and an anecdote. The broader point that we can't just turn these things on and off is 100% correct, and one of the (many) things that people don't understand when talking about the power system and emissions. I don't know the details of wind and solar, but any system that deals with hundreds-to-thousands of megawatts can't just be spun up on a dime. Make a mistake, and things blow up.