Depends on the powerplant

Post #2,824 by JayMehaffey 7/25/01 9:20:02 PM Reply	Depends on the powerplant I thought that power output of plants was more variable than "all, standby, or nothing"? Depends on the type of power plant. Power plants that burn things generally have to maintain a certain temperature/pressure to operate. For example (pulling numbers out of the air), a 1000 MW/h plant might have to burn the same amount of gas for any production level between 1 and 250 MW/h because they have to reach a certain temperature before they can run the turbines. The reality is much more complex, because large power plants have multiple units, sometimes in different sizes. But the general idea is still there. Jay
Post #2,847 by tonytib 7/26/01 12:30:18 AM Reply	Nope, just takes a bit of energy to operate turbines although you can lose efficiency. I believe nuke plants can run at various power levels with roughly the same efficiency. Of course, my nuclear power experience was in submarines; we did a lot of load cycling (changing power levels all the time) and didn't worry too much about efficiency, other than the fact that we wanted the core to last the life of the sub. Again, steam-based power (e.g. fuel oil or coal) can run pretty well at lower power levels -- again I do have some naval experience with fuel oil systems (1200 psi superheated steam frigate) and IIRC efficiency at different powers isn't a big concern. However, while gas turbines can run at low power levels, they aren't very efficient. Gas turbines have incredible power to weight ratios, are moderate polluters, and are reasonably efficient when at high power. Many of the new power plants, including in California, are natural gas-powered turbines. These plants would be more binary -- you'd probably want to run each turbine at pretty much capacity or not at all. And, of course, it was natural gas pricing that went soaring, thus directly affecting the price of natural gas produced electricity. Tony
Post #2,853 by Ashton 7/26/01 2:47:42 AM Reply	Perzackly.. well approximately then - the big smoke screen, 'least in CA meeja, was the electricity rates, brokers yada yada. Omitted: CA's major boondoggle (if I heard the various versions ~ correctly) of - deciding not-to fund a rather inexpensive connection link to existing Texas gas lines, some moons ago. However correct that version - the journyalists were bitchin about moderate e- rates and missing gas prices of over $1.40/therm! This in the midst of all the hand wringing. (A mobile home heating bill in the cold snap was near $400; mostly gas - I saw it) Point being - none of these observers connected the gas costs commercially, too - as re the turbines! Echoes the quality of press coverage of M/sloth I suppose. (Maybe it ain't all the journyalists fault.. as the newspaper monopoly becomes ~6 national players all owned by: _____ whatever you call wannabe monopolists almost there). What readst thou, Hamlet? Words.. words..

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