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Old 10-09-2008, 07:29 PM   #47 (permalink)
roflwaffle
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Quote:
Originally Posted by Duffman View Post
This is entirely my point that proponts of renewables refuse to see, it doesnt scale in a linear fashon. Lets talk wind turbines because they are the most cost effective and realistic of the group. Wind turbines generate power on a cubic function of wind speed, that means if you double the wind speed you get 8X (yes I will say it again EIGHT TIMES) the power. Also wind turbines have a minimum windspeed before they start to turn. Turbines also have a max wind speed after which they shut down to prevent damage to themselves. So based on this there is a huge variability in power production and when wind is having a poor day, some other source must be there to pick up the slack. In addition to this, it is totally impossible to forcast forward any significant time period. Right now conventional powerplants do not run at peak rated power so it is not a problem but as renewables grab a larger share of the capacity on the grid they overcome that reserve that the reliables are holding.
The only way it doesn't scale linearly is if we try to replace our current grid mix with one source. It scales in a linear fashion, for the most part, given a mix of renewables sources. We need a baseload of wind/geothermal/solar w/ dispatchable hydro and biomass/biofuel, just like we need a baseload of coal/nuclear/NG with dispatchable NG/fuel oil. If you watch the video and possibly visit the project site, you can see that any local variability does not translate into a system wide drop. For example, if the sun isn't shining due to a storm moving in, the wind is moving, and providing electricity via wind turbines. This does require some degree of forecasting, but it is possible. Of course this ignores demand side management, so by the time we see a large enough roll out of renewables in the states to account for a significant portion of electricity production, any uncertainty in predictions can be easily accounted for via demand side management.
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