Wednesday, July 23, 2008

 

A Caveat for Green Energy

There are several downside things to production of Green Energy, energy whose production does not create CO2. The best one, nuclear power, produces long lived radioactive remnants. Hydroelectric requires dams and generally the loss of rivers to the man-made lakes behind the dams (and a block to migrating fish). The more popular ones, wind and solar, have their own problems--bird and bat chopping and heavy metal contamination--but the main thing wrong is that the wind does not always blow and the sun does not always shine, while our need for power is generally constant. So if you want to rely on wind and solar, you also have to have conventional power plants to take up the slack when the wind dies down and the sun goes down or is occluded. And that 'back up' conventional power plant (or plants) has to have the capacity to provide all of the communities' power needs. If this supposition of mine is mistaken, I would love to hear how I'm getting it wrong.

There is a second problem, however, coming from the nimbleness of the conventional 'back up' power plant, or rather the lack of it. A coal fired plant needs about 12 hours to react to increased demand for electrical power. It's not a lot better for nuke plants. (A watched pot never boils). So if you have coal fired plants as your 'back up', they have to be running at a capacity which would provide all of the communities' electrical power needs pretty much all the time. This sad fact reduces the wind mills and solar arrays backed up by coal fired plants to mere trinkets. They make us feel better about the community and its caring about CO2 production, but they reduce the CO2 output very little, if any.

Power plants using natural gas are more nimble and can pump up the power in response to, say, the wind dying down, in a matter of minutes. So, if you really want to reduce CO2 production (although I think that is an absolutely wasted priority) by building thousands of wind mills (as T. Boone Pickens and Al Gore propose) their 'back up' power plants had better be nukes or fueled by natural gas, or you're just fooling yourself.

Over half of the power plants in America are coal fired. Less than a fifth are natural gas. A full fifth are nukes.

Oh yeah, and the popular green energy production is very, very expensive.

So suck it up, poor people; it's the planet we're saving (supposedly).

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Comments:
By far the best primers on the engineering problems of "alternative energy" that I've seen are those written by Steven Den Beste in his old USS Clueless blog*. See the following posts, particularly:

First pass
Specific sources
Biodiesel

* Note that he stopped writing that blog and is not interested in debating any of the points made there.
 
Thanks, Doug. Those were helpful. Shame he's stopped now.
 
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