Monday, October 26, 2009

Windy City

No not Chicago but rather Cambridge Mass. The Big O showed up at M.I.T the other day to tout stimulus funds being thrown their way for wind energy research To wit: "In fact, in just a few weeks, right here in Boston, workers will break ground on a new Wind Technology Testing Center, a project made possible through a $25 million Recovery Act investment as well as through the support of Massachusetts and its partners."

Well peachy keen I'm sure and there are likely far less worthy projects, whatever their shovel relational statuses might be, that have lapped up milk squirted from the swollen stimulus teat, damning though that faint praise might be. Among the advantages touted for the Wind Technology Testing Center is that it will be able to test and analyze wind turbine blades as long as 300ft.

Good frakkin' grief. One can only assume that such behemoths are in the offing if testing is being essayed and what a monstrosity such a device portends. A wind turbine with 300 ft. blades will perforce be 600ft wide and will likely stand on a 400 ft. tower which projects the thing 700 ft. into the sky, at a minimum. A hazard to aviation is likely to be the least of such an installation's liabilities.

It is axiomatic in the world of aerodynamics that, in general, the larger the propellor the more efficiently engine power is transmitted to the air. This principle works just as well in reverse with large wind turbines being, again in general, more efficient extractors of power from a moving air mass. With aircraft there is a point of diminishing returns that can result in props that are so large that planes must use ever longer and more unwieldy, landing gear so that the spinning prop tips do not strike the ground. In addition large propellors frequently require gearing to efficiently match engine rpm to the lower more efficient prop speeds required.

Giant wind turbines can turn very slowly while extracting power very efficiently but they are beset by structural problems that suffer from their own sorts of diminishing returns. The longer the blade the more robust the structure required and therefore heavier which is obvious but the loads seen by such structures increase as the cube of their size so needed structural strength also cubes. I am fairly certain that a 300 ft. long turbine blade is at the raw ragged edge of the diminishing return curve or perhaps a bit past it. Such a long structure will have to be very stiff to both avoid destructive resonances and to survive high storm wind speeds that will severely stress all parts of the turbine even with the blades feathered.

Naturally not just the turbine blades will have to be much stronger but so will every other part of the installation which will subject to the cruelties of the cube law. A 600 ft. turbine will likely need to be over three times as strong, and three times the weight of the currently typical 300 ft. turbine. Three times the cost, and possibly much more, is quite likely as well.

The support structure for this olympian wind catcher will need to be far larger and stronger, to put it mildly. The steel pylon holding up this rig will need to be at least 400 ft. tall and likely higher to avoid aero interference with the ground. In like wise such a huge whirly thing will discombobulate the air flow so much that siting another turbine closer than a couple of miles will be inadvisable.

So this mega-puppy is going to eat up a lot of land, several hundred acres at a very minimum. The low frequency high decibel noises it will make may well create seismic stresses in any structure nearby. And there may be significant high frequency noise as well. After all the tips of those football field length blades will likely be hustling along at a couple of hundred mph which implies soprano screams from tortured air molecules. Fun!

A unit this size will likely be able to generate 10 megawatts of power at whatever its optimal wind speed will be. Impressive until one remembers that it will be generating that much juice maybe 20 percent of the time, if it's lucky. Considering that such an installation likely will cost at least 20 million dollars exclusive of support and auxillary hardware that's going to be some expensive watt/hours indeed.

It will require at least a hundred such turbines to produce power similar to a large hydrocarbon fueled powerplant or a medium sized nuclear reactor and of course in practice they will at best produce a fifth of the power of either of those alternatives in any given year. This means that at least 500 of those massive turbines, sited trans-regionally, will be required to equal the yearly output of one large conventional power station. I for one am afraid to calculate the stupendous required mega-tonnages of steel, concrete, advanced composites, aluminum, etc., etc. and we certainly don't want to forget the hundreds of thousands of acres of turbine sites and the thousands of miles of access roads needed for site building, maintenance, and transmission tower routes. What part of this scenario could be considered by anyone to be "low impact"? Compared to all this a nuclear plant lies extremely lightly on its measly couple of hundred acres of land.

Even if it's decided that such giant turbines are unnecessary the need for vast tracts of land and millions of tons of materiel is only aggravated not ameliorated if we are, as eco-warriors relentlessly aver, trying to substantially replace conventionally generated electricity. I assume that said eco-warriors and those in sympathy to their aims are simply unaware of the multi-trillion dollar tab for such bizarre extravagancies or are blithely unconcerned about it. We poor saps who will have to pay the tab for such grandiose fever dreams should damned well be concerned. Exactly how large an increase in our energy bill are we willing to tolerate? A doubling? Tripling? Quintupling?

How far are we willing to go to finance the modern Quixotes' tilting at wind turbines in pursuit of a fraction of a percent reduction of CO2 emissions in the next five or six decades? Millions of over-taxed lower/middle class Dulcineas will almost certainly spurn the eco-Quixotes' trillion dollar affections for the great green romantic energy scams of the 21st century. Oh we love the impossible dream right enough but we're decidedly lukewarm about the insanely expensive and economy destroying dream.

1 Comments:

Blogger Largo said...

It is a shame that your blog posts have few comments. I have just come upon it, and have been reading back. Among your many delightful turns of phrase, I saw this gem:

"""These days being labeled a child abuser is very nearly preferable to being labeled a partisan or a divisive influence. Tellingly this invective current flows primarily from Dem. to Rep. through the diode of progressive sanctimony."""

I just wanted to tell you sir: you sure can write.

November 15, 2009 at 3:44 AM  

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