HAWT or Not?
Why actually, this is a HAWT--horizontal axis wind turbine, as opposed to a vertical axis wind turbine.
Sorry... I spent most of today at a wind power seminar given by this guy Paul Gipe--he has done just about everything, from climbing up towers to build and service homemade turbines to working on wind turbine policy with power companies and governments. He came across as very experienced and a bit of a grump, but that totally makes sense and is a bit refreshing in the field of, "Oh, this renewable power source will save the earth," optimism--he tempers it with a lot of real experience.
For instance, in regards to bird kills from wind turbines: he fully admits that it is a real problem--for instance, Altamont Pass kills a bunch of raptors each year; he recommended better consultation with ornithologists in future developments; but the two sides can be resolved, hopefully.
He also ran through a lot of the failed branches in the evoluation of the technology--for instance, you seldom see those vertical axis wind turbines in Altamont Pass running--that's because the technology sucked, and as he put it, they "haven't been stamped into beer cans," as they should be. They are less efficient than HAWTs, for instance. Second, although the gearing is at the bottom, which is supposed to improve maintenance, there is a top bearing which gets a whole lot of vibration and wear, thus still requiring a crane for maintenance. Third, they are instrinsically lower (to the ground) than HAWTs: wind velocity rises rapidly with altitude (and power generation is a cubic relationship to the velocity), thus lowering their power collection ability.
Overall, it made me very optimistic about wind power as a large-scale resource (e.g., the way that Europe is moving a lot of its generation to wind: 36,000 MW capacity vs. 7,000 MW in North America). However, one of the reasons I went to the seminar was because I'm thinking, in the back of my mind, that someday it might be neat to have an off-grid house with PVs and a windmill. Gipe was not terribly enthusiastic about the current generation of small/homeowner/hobbyist wind turbines--he described it as a field full of "charlatans, scams, and flakes," as well as pointing out that the technology in these small scale turbines is twenty years behind the technology used in large-scale generation. The field is full of overzealous claims and crackpot inventors. The reliability of the technology, as you would expect, is not great, and a seriously large turbine is needed for a house-load sized load. Also, having to do maintenance up on a 100 foot tower does not sound fun. Overall, it made me a lot cooler on the idea...
Also, the last portion of the seminar ended up being a three-person discussion between a few audience members and the speaker--"What do you think of this turbine? What about the power rating curve on this one?" Despite this annoyance, and the length of the talk, it was pretty interesting to go.
posted by Bats @ 12:38 AM
9 comments
9 Comments:
Did the guy have anything to say on how a power grid can absorb lots of small scale wind farms? Seems a solveable but not solved problem to me.
Crap. That was an Omri comment.
is it feasible to build some type of caging around the towers to prevent birds from being killed? or would that completely ruin the ability to collect the wind power or decrease it enough to make it undesirable?
ttfn,
antee jean
yeah, what antee jean said. it works for household fans. in my house we have lost like no birds at all this summer to them flying violently into fans and smashing themselves to bits.
josakana
He did talk a bit about distributed wind turbines, and the leasing of various farmers' lands in a large-scale arrangement. I think these were mid-scale (as opposed to small scale/homeowner size) wind turbines, so they were higher-technology units than the smaller units. He has an article on this technology on his website: Community Wind:The Third Way.
As for bird kills, I don't think any type of caging would be a realistic technology. First, the mesh would have to be relatively small to actually stop birdstrikes. Second, the guard would have to be huge--the large-scale windmills nowadays are 100 m in diameter. Third, that grid would provide an excellent area to collect flying trash, or for that matter, let birds nest on less-windy days. Finally, and most important, it probably would destroy the efficiency of the turbine. By way of analogy, some wind farms are laid out in a huge rectangular grid, with large distances between the turbines. Despite the spacing, the ones on the inside of the rectangle have the worst power production (wind "robbed" by the other turbines), and the worst maintenance/downtime records (suffer from turbulence generated by other turbines).
They have researched various methods to try to scare off birds--painting various patterns, whistles, etc. (especially in Europe), but Gipe did not think there was evidence that they worked. The best approach, he thought, was to include an ornithologist on the siting team, and figure out the lowest travel density areas for birds.
An article on his website is: Sobering Altamont Bird Report Issued.
How much does the bird kill issue really matter due to direct/indirect cost questions?
[That is, are more birds killed by wind turbines than would have been killed by smog produced by coal-burning plants?]
A very good point--I don't know of any calculations and guesses along those lines, but by way of anology, somebody else I know compared the bird mortality of the windmill on the shore at Toronto with glass skyscrapers, and the buildings were an order of magnitude or two worse. I believe that Altamont is particularly bad because there are plenty of small mammals for the raptors to eat in the ground around the wind turbines.
I wonder how long it would take for evolution to start breeding a turbine avoidance instinct in raptors.
Charlatans, Scams, and Flakes," - You certainly hit the nail on the head with that one! How about that outfit in Cheyenne, Wyoming that has changed names several times and sells stock at different prices at different times according to how they talk you into it ? Gee's I wonder how the stockholders feel about that or do they even know? Granted it is a vertical axis turbine and they have been squandering shareholders money with the futile attempt to compete with hawts for years and have nothing but models to show for the milliions invested ! They use the ploy of a loan with stock as collateral and string you along until they find another money investor and give you back a minor amount and convert your initial investment to wortless stock. Is that a scam or what?
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