In reply to Jeff Fink's message of Sun, 8 Mar 2009 21:27:57 -0400: Hi Jeff,
Thanks for clearing this up. >Large base load nuclear and coal fired plants are not unresponsive. They >can reduce load from 100% to 50% in a matter of minutes. The water volume >is not an issue. > >Utilities are about producing power as cheaply as possible. It is expensive >to run these large units at reduced power for several reasons that go beyond >serious efficiency losses. Large daily load swings rapidly consume thermal >fatigue life of major components. In the case of nuclear, some of the main >areas of concern are components that are irreplaceable. Examples are the >various pipe connections to reactor vessels and steam generators. > >Operating coal units at reduced load causes accelerated corrosion of some >components, particularly the regenerative air heater that removes waste heat >from the exhaust gas and transfers the heat to the incoming combustion air. >These air heaters are huge rotating cylinders filled with tons of steel heat >absorbing elements. At low loads, these heaters suffer cold end corrosion >that rots out the elements requiring expensive repairs. Low load operation >also causes erosion of expensive control valve seats and cavitation damage. >It is not cost effective to allow wind turbines to force these base load >units into low load operation. > >Coal fired plants burn coal dust. The dust is produced by pulverizing the >coal in huge ball mills then blowing it into the furnace. This process >approximates the characteristics of a gaseous fuel. > >Jeff [snip] Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/Project.html
