Help needed from civil engineers and other technical minds.

[French G.]

Hi, for my own interest and maybe later editorializing I am trying to figure some life cycle energy costs of some equipment, specifically wind turbines. I will attempt to spec out the turbines myself to determine material content. What I will be focusing on is total energy cost to build and install one of these things, so I am looking at how many Khwh does it take to smelt a ton of steel, how much diesel does it take to get the necessary ore, average recycled steel content and it's effect on energy use, some idea of how to estimate rough energy expenditure to bring raw steel to the desired shapes. That is an example for one material. I would need to do the same puzzling on aluminum, concrete, copper, fiberglass, plastic, and carbon fiber. At that point I can look at fuel costs to transport pieces to the site as well as fuel costs to transport workers daily, fuel cost for the necessary road building and site excavation, and so on. My premise is that a wind turbine under ideal generating conditions will be 2/3 or more into its projected service life before it shows a net gain in energy generation. I want to see if I am right. Any resources you can point me to would be appreciated.  

     I will totally ignore until the editorializing that a wind system as a supplement to a coal based system such as we have in the U.S. does diddly since you still keep the coal plant fully online due to the unpredictable nature of wind. The reason for all this is I used to believe in "green" energy until a rather undemocratic/unrepresentative process forced them on me in the future, barring litigation.  I am coming to the conclusion that what an industrial wind turbine generates is money for the operator that gets the tax breaks as well as an out for the energy companies to meet the 7% required renewable in their portfolio that is coming thanks to D.C.   I am of the opinion that resources spent building these would be better conserved. I don't know how to encourage Americans to conserve, maybe an idea which I despise being individual tax credits for sound energy use practices. I have always despised a NIMBY, now I am one. The caveat is tell me you are going to build a breeder reactor in my county and I will sign on to work construction, then try to get hired as security when it is done. I just don't want to see a place who's two assets are an agrarian lifestyle and the last undamaged views in the east get sold down the river for crap that makes no enviromental sense. To give you a sense of this place, trouble was had over someone who wanted a subdivision. Ghastly you say? Yep, subdivision was going to be several 200acre chunks, followed by 6 other pieces as small as a piddly 50 acres! Can't have the place getting too crowded you know. Pretty rare within 200 miles of D.C. I'd say, that is big land out here, small by western standards.

 I did what I can, I am getting geothermal in my new house backed by an overabundance of insulation. I may one day get a personal wind turbine, not to save the world, but to give me an alternate energy source. Engines fascinate me, so I forsee biodiesel tinkering in my future.  I still play with race cars, tow them with a 454 GMC, and eat red meat. I will never be some holier than though, birkenstock wearing, Prius driving freegan, but I try to realize my impact on global energy use. This crap(industrial wind) makes no sense to me. Just the latest coal mine to come to Appalachia, destroy communities, and never deliver on promises.

[DrAmazon]

If you do manage to get this figured out, please let us know.  I'd be very interested to see this calculation and include it in the "energy" components of my courses.

[drewtam]

Civies dont really work with turbines at all; turbines move, civies only deal with things that dont move (and if what civies make do move they did something seriously terribly wrong).

What you want is a Mechanical Eng for your calc. They deal with things that move and how to make them.

But any sort of artificial energy calc, will be bunk anyway.
What you are asking is the energy required to, say, cast the structural parts, right?
But what if its actually fiberglass layup for the blades, instead of casting? Thats not artificial mechanical/electrical/chemical energy, thats labor energy.

If you really look at what it takes to make something, anything; most of the cost is labor. And that is really important to any "energy" calc.
Why? You might ask... Because the cost of labor is then used to buy houses (which require energy to build), cars (energy), food(energy), utilities (energy), or anything else a human buys with thier wages. There is a huge ENERGY cost association with any labor, from the guy doing the work, to the manager, sales, engineers, banking, warehousing, the CEO, back down to the stock holders.

In the final analysis then what is really more efficient in terms of energy? Is it not the system that COSTS less!? The system that costs less uses fewer exotic materials which requires alot of energy and labor to form, it requires less maintainance for less labor, it uses cheap high energy fuel that has lower labor cost, and is consistant in usefulness negating the requirement for backup systems (which factors in a whole new system of cost-energy), it requires less transportation from manufacturing to consumer, etc, etc, etc.

So how does one figure out whether a system has finally made a net energy gain/benefit... by considering the ever important question:
Does it make a profit?

There are only a few externalities to this method of comparison:

Government subsidies/taxes/regulation (distorts prices)
Enviromental considerations (pollution- makes things cheaper than they should be, but depends on natures ability to handle/breakdown/dilute)
  and in a distant third
Economies of scale (there is no physical reason why Apple machines and thier software is more expensive than PC's, except more PCs are made with more competition)

SO to answer your question, in my very humble opinion, I would suggest that you look at how much the hypothetical wind turbine costs for you to build and maintain, and compare that to what power it will generate at price. Use that to figure out how long it will take to make profit and that is when you will make a net energy gain.

Drew

Edit: PS I am a Mech E

[French G.]

I can understand the does it make a profit method, which if you look at ideal output and cost of electricity in KwH can be easily figured. I really want to lay out the energy usage because as you noted subsidies skew everything and also the main justification for green energy devices is "gee, look at all the oil they save!" I want all the oil they don't save listed in detail because if we just talk about profit I don't want to hear some Ayn Rand reject say "we don't care about profit, we want to save the world". Most of this can be illustrated. I understand labor, but will ignore it, figure people have to work somewhere, for that reason I probably wouldn't even look at fuel used to transport workers, even though most people don't drive 50+ miles to work. Having been knee deep in a fiar amount of carbon fiber and fiberglass I know you don't get a direct energy cost for a finished composite. It still took energy to make the base materials. Making concrete, steel, aluminum takes a finite amount of energy, so does running a bulldozer for an hour. Just have to figure out what the per unit is and how much we are talking about. Again, I can point simply to cost vs generation, but I want it spelled out to convince people who would rather keep a platitiude in their head such as "windmills save the world". Thank you for your input, it does give me some things to consider.

[drewtam]

What you are looking for then, is a raw material energy cost?

If your going set arbitrary boundaries on what energy you will consider as part of the cost; it would be best to really lay out specifically what energy you want to consider.

For example:
You want:
the energy to raise temp of the iron ore to the melting point,
the energy to remove impurities from the liquid ore
the energy to add the proper carbon and other metals to create steel (this where a whole 'nother subset of energy calcs come in cause there is energy required to extract these metals from ore)
the energy required to maintian the proper temp of the cast mold
the energy to run the cutters

But you dont want:
the energy to power the lights of the steel mill
the energy to QC the metal to proper standards
the energy to run the fans for the workers

I think you get my point. What you are asking for is a fairly arbitrary set of energy boundaries, and are consumption numbers that a steel mill, in this example, wouldn't separate. Or if they did have the exact values wouldnt release to the public.
But for the sake of estimation, one can look up the melting point of iron ore, and the specific heat of the rock to find the energy required: ~1540*C, .44J/(gm K), =  669 J/gm = 186e-6 kW_hr/gm. This from 2mins of google and a 10sec calculation.

The fiber of carbon fiber can be done much the same way; as i understand, its just a chemical process induced by heating.
But the epoxy/matrix is going to be some chemical process, and I dont know much about Chem E. All I know are the material props, polymers are out of my league.

Drew

[280plus]

Heh, I just saw a thing on "Number 7" East Chicago, Indiana. Largest blast furnace in North America. There is also the energy needed just to get the raw material from ground level to the top of the thing 310 ft up. It produces 7 tons of liquid iron in one minute. It is fueled by coke. Thought this info might be helpful.