"...Hoover dam - it has a capacity factor of only 26%..."
So you're saying Hoover Dam must generate a gross 100Mw for a net sendout of 26Mw? Are all hydro's that innefficient?
If that's the case, then you're also saying a wind turbine must gross 300watts for every 100 watts it sends to the grid? I guess I need to learn more about wind turbines, I didn't think they required that much power to maintain themselves...
Or am I confused, per normal? ;^)
Just curious.
You're confused :-) Here is how it goes. Capacity factor is nothing to do with losses/efficiency in the actual generation equipment, rather it is a measure of what percentage of time a particular plant is actually being used to generate electricity.
A particular generating plant has a "nameplate capacity". This is measured in MW. For the Hoover Dam it is 2074MW.
If it were generating 100% of the time it would generate 2074 * 24 * 365 MWh (Megawatt-hours) of electricity per year. That comes to 18,168,240 MWh per year.
Now we know that it actually generates 4,800,000 MWh per year on average. So the capacity factor of the Hoover dam is
4,800,000/18,168,240 = 26%
Source for the Hoover dam: http://www.usbr.gov/lc/hooverdam/faqs/powerfaq.html
If