Small windpower a scam ? Survey says SO

mike95490

A recent test in Zeeland ( a Dutch province)
http://www.lowtechmagazine.com/2009/04/small-windmills-test-results.html
"implies" nearly useless, if you have less than 4 meters/sec wind annual average

12 machines were tested
http://provincie.zeeland.nl/milieu_natuur/windenergie/kleine_windturbines/de_turbines

icarus

Re: Small windpower a scam ? Survey says SO

Does anybody here sound surprised?

Tony

dwh

Re: Small windpower a scam ? Survey says SO

I don't think this thread should have been moved to the scams section.

I think that the original post shows a legitimate test of small wind power systems, and thus it should be a sticky in the wind power section.

niel

Re: Small windpower a scam ? Survey says SO

very well, i can move it to wind, but as to a sticky if others here believe it to be worthy enough we'll give it such a designation.

dwh

Re: Small windpower a scam ? Survey says SO

Sorry, I should have been clearer - my reasoning for making it sticky is that it might help to answer some of the "newbie" type questions by showing a legit test of small wind power systems.

Windsun has stated that one of the big time wasters in their store is answering such questions.

boB

Re: Small windpower a scam ? Survey says SO

Bigger is better, but 3.8 meters per second is what... 8.5 MPH ?? VERY low and un-practical wind speed. Barely even cut-in wind speed for most turbines, large or small. I'd say this test is flawed for that very reason.

And did the say how high the turbines were ? And their larger reference turbine ? Is that reference turbine the tower in the background that is WAY up there ? (probably not, but I don't know)

boB

BB.

Re: Small windpower a scam ? Survey says SO

According the the PDF of the specs. for the large wind turbine, the standard tower is 30 meters with an option to 40 meters.

Interestingly, the system is a AC/DC/AC inverter system (not a synchronous 3 phase motor to the AC power line frequency).

Quick specs:

ENCLOSURE A: TECHNICAL DATA OF THE LAGERWEY 18 meter /80 kWatt WINDTURBINE 
GENERAL 
design according to    NEN 6096 
certified by     CIWI (ECN) - Holland 
cut in  windspeed    3 m/sec. 
nom. windspeed    12 m/sec. 
cut out  operating windspeed    25 m/sec. 
max. survive windspeed      60 m/sec. 
nominal power    80 kW 
specific power     315 W/m2 
calculated lifetime    min. 20 years

So--given that the total installed cost of the one large wind turbine was about the same as the 12 smaller wind turbines in total (30 meters high, in a windy region of the Netherlands) and the one large system generated about 20x the amount of power...

Sort of indicates that small wind power is not really competitive...

Compare the largest of the "small systems" (Montana vs LW18-80):

Euro 18,508 / 2,691 kWhrs per year = Euro 6.79 per kWhr per year (Montana WT)
Euro 190,000 / 140,000 kWhrs = Euro 1.36 per kWhr per year (Large WT)

Even the best small turbine was still 1/5 as cost efficient as the large turbine (who knows maintenance costs + lifetime comparisons)...

-Bill

BB.

Re: Small windpower a scam ? Survey says SO

One other interesting point to ponder... How far off most of the production numbers were (if I read the Dutch Specs. correctly).

Link to Article (in OP--Measured Yield).
Link to translated Dutch specs. (yearly power estimates from Vendors):

- Energy Ball v100 (4,304 euro) : 73 kWh per year, corresponding to an average output of 8.3 watts
Predicted by Vendor: Power: 0.5 kW with the supplier an estimated yield of 350 kWh / year

• Prediction Accuracy: 21% of predicted output

- Ampair 600 (8,925 euro) : 245 kWh per year or an average output of 28 watts
Predicted by Vendor: Power: 0.6 kW with a supplier by the estimated yield of 1,500 kWh / year

• Prediction Accuracy: 16% of predicted output

- Turby (21,350 euro) : 247 kWh per year or an average output of 28.1 watts
Power: 2 kW with the supplier an estimated yield of 1485 kWh / year

• Prediction Accuracy: 17% of predicted output

- Airdolphin (17,548 euro) : 393 kWh per year or an average output of 44.8 watts
Power: 1 kW by a supplier estimated yield of 1800 kWh / year

• Prediction Accuracy: 22% of predicted output

- WRE 030 (29,512 euro) : 404 kWh per year or an average output of 46 watts
Power: 3 kW, according to the supplier with an estimated yield of 900 kWh / year

• Prediction Accuracy: 45% of predicted output

- WRE 060 (37,187 euro) : 485 kWh per year or an average output of 55.4 watts
Power: 6 kW, according to the supplier with an estimated yield of 6000 kWh / year

• Prediction Accuracy: 8% of predicted output

- Passaat (9,239 euro) : 578 kWh per year or an average output of 66 watts
Power: 1.4 kW with a supplier by the estimated yield of 1250 kWh / year

• Prediction Accuracy: 46% of predicted output

- Skystream (10,742 euro) : 2,109 kWh per year or an average power output of 240.7 watts
Power: 1.8 kW with the supplier an estimated yield of 1360 kWh / year

• Prediction Accuracy: 155% of predicted output

- Montana (18,508 euro) : 2,691 kWh per year or an average power output of 307 watts.
Power: 5 kW with a supplier by the estimated yield of 4500 kWh / year

• Prediction Accuracy: 60% of predicted output

Most of them average around 20% of predicted performance--And only Skystream exceeded predicted performance!

-Bill

boB

Re: Small windpower a scam ? Survey says SO

At what wind speed is the yearly "estimated" yield at for these
turbines ? 8.5 MPH ?

boB

BB.

Re: Small windpower a scam ? Survey says SO

The second comment in the original posted link:

The test was funded by:
- Stichting Zeeuwind (wind energy)
- Greenlab (small scale renewable energy, focused on wind energy and tidal energy)
- DELTA NV (gas, electricity, solar, internet, tv, water)
- Provincie Zeeland (government)
- Gemeente Sluis (local government).
This test was not designed to give the small wind industry a bad name, on the contrary. These small windmills are designed and promoted for use in a built-up environment, where the average wind speeds are almost always lower than 8.5 mph. They were friendly enough to install them in an unobstructed area, and they decided not to include the results from November 2007 to March 2008, when many windmills showed problems.
See the windmap of Holland and the article we published before:
http://www.nkpw.nl/images/stories/KNMI%20Windsnelheid%201971%202000.jpg
http://www.lowtechmagazine.com/2008/09/urban-windmills.html

From the 2008 article (2nd link above) there is a lot more details about the installation/testing.

Basically, went to a very windy province in Netherlands, in clear/open fields, and installed wind turbines advertised for urban areas (small rotors, short towers, lots of wind obstructions)--so this was "ideal" testing.

From this PDF file, the average wind at the test site (in meters per second, by month and 1 year average--slightly winder than average--I am guessing this is at 10 meter height since they were documenting smaller wind turbines on 10-13 meter tall towers--I think):

Maand (month)
apr-08 3,5 m/s
mei-08 3,7 
jun-08 3,4 
jul-08 3,4 
aug-08 3,6 
sep-08 3,4 
okt-08 3,2 
nov-08 4,4 
dec-08 3,7
jan-09 4,4
feb-09 3,4
mrt-09 4,4 
Gemiddeld 3,8 m/s (1 year average)

Conversion is 2.2369362920544 * m/s = MPH

3.2 m/s = 7.1 mph
3.5 m/s = 7.8 mph
3.8 m/s = 8.5 mph
4.4 m/s = 9.8 mph

Interestingly--I found out you can use Google Language to translate PDF files as well as websites (graphics will not be pretty--but at least you can read the text).

In the end, the 2008 article says:

At lower average wind speeds, even very small changes can make a huge difference. According to the Carbon Trust the cut-in speed of a small wind turbine (the moment it starts producing energy) is between 3 and 4 metres per second. This is close to the average wind speed on land in rather windy countries like Belgium and the Netherlands.

A test by the Carbon Trust (see graphics below) showed that a windmill receiving an average wind speed of 4.5 metres per second produced 7 times more energy than a windmill receiving an average wind speed of 3 metres per second – because the latter is not operating most of the time since it does not reach its cut-in speed. While large wind turbines have an average capacity factor of 28 to 35 percent, small windmills only achieve 15 to 20 percent of their capacity in rural areas and only 10 percent in urban areas.

Regarding tower height--Scaling a few of the pictures against rotor diameter seems to show the turbines are around 12-13 meters high (~40 feet?)... And the articles talk about the rarity of 10 meter wind maps (vs 75 meter wind maps that which are widely available)--so I would guess the 12 test towers are at least 10 meters tall.

The spec. for the 18 meter turbine was listed as 30 meter standard, 40 meter option (100' - 132' tall towers).

So, the small/large turbines are not probably not on the same height towers--but are mounted per the mfg. standard recommendations (10 meter/30' minimum tower above obstructions).

In the end--the tests are not fair--because wind is not "fair". Large swept area on tall towers in windy locations are pretty much required for a good return on investment.

-Bill

WisJim

Re: Small windpower a scam ? Survey says SO

This "test" was certainly a joke, but it does make an important point. Tiny vertical axis machines don't produce enough power to bother with, and short towers don't work. I would never recommend anything less than 60 feet for a tower, and 120 is certainly much better. It is funny to me that the Skystream did the best in these tests, as it is gaining a reputation in the USA of not performing reliably or up to predictions. There are some good machines out there, but they generally have at least a 10 foot diameter rotor, and are mounted on tall towers by reputable installers, in areas with at least 10mph average windspeed.

WillWinston

Re: Small windpower a scam ? Survey says SO

I certainly do not consider this a 'valid test'

a wind speed of below 10 mph is just not going to give reasonable numbers

since the energy in wind goes up as the cube of the wind speed, any average wind speed under 10 mph is a very poor wind power site, and therefore a poor test


I have experieince with an Air 403 and while I can't say it is perfect or even 'state of the art' any more

I can say that it paid for itself in a 2 to 3 years

but

I have a windy site -- average at least 12 mph with sustained high wind days on a hill top in Wisconsin

a large unit would probably have 'gone walk about' from some of the storms the little 403 handled just fine ( I did lose a blade to a bird strike $74)

and blew out my trace inverter from a lightning strike

but

the 403 just kept on turning out the watts

icarus

Re: Small windpower a scam ? Survey says SO

Aside from the basic (un) reliability of small scale wind machines,,, IMHO the biggest mistake people make with regards to small scale wind is over estimating how hard the wind is REALLY blowing,,, on average. A 12 mph average is a REALLY windy place. If you are not constantly irritated about the wind "blowing all the time" disrupting activity, you probably don't have enough wind to make it even worth a cheap try.

Tony

WillWinston

Re: Small windpower a scam ? Survey says SO

I agree if you do not have a windy site it is going to be a long payback


If you don't have 10mph or more (get it professionally measured if possible) it is like putting up a 2000 watt solar panel array in the middle of the rain forest on the olympic pennisula under a heavy spruce canopy

dwh

Re: Small windpower a scam ? Survey says SO

Perfect!

I stand by my point; I didn't say the test was "fair" or "valid" or any other description except "legit" - legitimate.

But actually, it was valid, if for no other reason than that it demonstrated conclusively that an 8.5mph average wind speed is too low for most small wind turbines to put out a significant amount of power. That is a "valid" conclusion resulting from this test (an expensive way to reach that conclusion yes, but experiments can sometimes be expensive for little or no return).

Nevertheless, it was legitimate; They set the units up next to each other, in what they consider to be a windy area of their country, they monitored, they ran it for a year.

No hype, no "optimum conditions" BS, just a simple little "real world" experiment.


Now, as to my reasoning for this thread being a sticky - that it would be a good thread to answer some newbie questions - again, I stand by that. With the posts that this thread has already generated, it has become very informative.

For example:

* 8.5mph average wind speed is too low for most small wind turbines (but not all).

* Any average wind speed under 10 mph is a very poor wind power site.

* Most people overestimate the average wind in their area.

* The people who setup this experiment overestimated the average wind for the test site (they expected 6 meters per second average).

* 10 meters height is too low for most turbines in most places.

* A windmill receiving an average wind speed of 4.5 meters per second produces 7 times more energy than a windmill receiving an average wind speed of 3 meters per second.

* Small windmills only achieve 15 to 20 percent of their capacity in rural areas and only 10 percent in urban areas.

* The energy in wind goes up as the cube of the wind speed.

* The power output of a turbine is directly proportional to the swept area.

* When you double the radius of a turbine, you increase the swept area by a factor of four.

* 3 out of 12 (25%) of the small turbines in the one year test broke down.


This thread is practically a FAQ all by itself.

icarus

Re: Small windpower a scam ? Survey says SO

Dwh,

Well said!

It speaks clearly as to why small scale wind proves not to be very practicable for most people. The 10 meter rule is hard enough for most people. The idea of raising anything 10 meters off the ground sounds easy,,, until you have to do it. Add to that the idea of guying and bracing that load against huge potential storm loading,,, and it is no wonder that so many of them fail.

I would love to put up a nice, cheap, small (200-400 watt) rig to augment our charging,,, but I don't think one exist. On the other hand I could mount on on a pole on the ice and hmmm!

Tony

PS You might cite your stats a bit just to give them some weight

boB

Re: Small windpower a scam ? Survey says SO

WillWinston wrote: »

I certainly do not consider this a 'valid test' a wind speed of below 10 mph is just not going to give reasonable numbers

But this this rip-roaring 8.5 MPH wind speed is the windiest it gets in Holland ! (I is a high wind site you know)

There just ain't much power available at 8.5 MPH ! And you can't just put bigger blades on them either and expect them to last at higher wind speeds.

At a windier site, these small turbines would certainly work better than in this test. But, here was your wind speed test for low wind speed... Next ! (next test that is)

boB

icarus

Re: Small windpower a scam ? Survey says SO

I just had a chuckle!

As I have always wished for a simple small wind genny,,, and this thread always relights that fire,, I went looking and our Local Canadian tire has the Air X 400 on sale for ~$550 usd net,,, not too bad for a toy if one wanted to play.

So I went to the Southwest wind power site just to look over the specs and I found the windspeed Vs output chart. At 20 mph it puts out 100 watts,,, but what is really funny is when you look at the chart below 15mph it shows that it generates LESS than zero watts,,, so in fact it is a loser! LOL http://www.windenergy.com/documents/spec_sheets/3-CMLT-1339-01_Air_X_Spec.pdf

I guess for the same $550 I could buy two more Sun 90's for another 180 watts,,something I would need a consistent ~25mph to get close to with the Air X. Not only that,, but in 24/7 service I would bet that the PV panels will still be putting out rated current 5 years from now,,, not likely the Air X.

180 watts of PV/50%=90 watts net X 4 hours/day average=360 whd,, averaged over 30 days of 1/2 sun you would get 5.4kwh. over a year=~65kwh/yr.

Air X 400 putting out 100 watts 4 hours/day/50% =200 wh/day X (?) 50% windy days X 365 might be 36kwh. That's figuring 20 mph for 4 hours 1/2 the days of the year,,, not likely where I am. I get lots of wind in spurts,,but calm nights are common winter and summer, days with 5-10 mph quite common,, days with 25-20 1 day in 10 in the summer,, 1 in 5 in the winter.



Tony

niel

Re: Small windpower a scam ? Survey says SO

you're right tony and to add to that the air x will upon hitting 28mph will shut itself down from production for about 5 minutes meaning that the 20mph winds if producing gusts will render the thing useless for production. as was told to me it saw about 4a typically in the columbus, ohio area when it was able to make something. too low is obvious and too high cuts it out and it needs a sweet spot to be useful. add to that blade replacements and other maintenance items associated with it and it turns out to be a money pit for its level of power production.:grr

WillWinston

Re: Small windpower a scam ? Survey says SO

I will just reinterate my personal experience with an Air 403


It powered a full size refrigerator for almost 3 years

It still works fine

how many solar panels pay for themselves in 3 years ?

as for the Trace inverter /charger it has failed twice -- once from lightning and the current unrepaired failure

The chart at SWW is clearly a typo since the unit does not consume any power at all


The chart in my manual rates output at 30 KWHr per month in a 12 mph average
or about a KWHr per day

this is very close to my experience with the unit powering the fridge

it is a waste of money if you do not have at least a 10 mph average site

dwh

Re: Small windpower a scam ? Survey says SO

"The chart at SWW is clearly a typo since the unit does not consume any power at all"

The specs list a microprocessor control and electronic torque control...it's gotta consume something (but probably not "less than 0" ).

icarus

Re: Small windpower a scam ? Survey says SO

WillWinston wrote: »

I will just reinterate my personal experience with an Air 403


It powered a full size refrigerator for almost 3 years

It still works fine

how many solar panels pay for themselves in 3 years ?

as for the Trace inverter /charger it has failed twice -- once from lightning and the current unrepaired failure

The chart at SWW is clearly a typo since the unit does not consume any power at all


The chart in my manual rates output at 30 KWHr per month in a 12 mph average
or about a KWHr per day

this is very close to my experience with the unit powering the fridge

it is a waste of money if you do not have at least a 10 mph average site

Not to pick nits,,, but because any hardware performed for three years doesn't mean it
"paid for itself". For example,, assume for the moment that it produced 1kwh/day which is close to what the "advertised" rate would be. (pretty optimistic IMHO) you would get ~ 365 kwh/year. At $.12 grid power cost would return ~ $44 worth of power,, three years would be ~ $175 worth. Given the ~$600 cost,, it is hard to say that it paid for itself.

Now I am not saying it is not valuable to you (or to someone) but "paying for itself is somewhat relative.

Now my newest PV panel, puts out 90 watts. Using my own 50% rule of net/net off grid here is it's number. 90X50%=45 watts X 6 hours average X 365 = would be 98 kwh/year,,, $12 per year at a cost of ~$250. Roughly 1/3 the power at 1/2 the cost.

Now if you figure out which is more likely to put out as advertised, AND the life cycle cost,,, my money is with the PV panel.

Tony

In both cases I use some weather assumptions. In the wind,, we are assuming (according to SW wind) a 12mph AVEARGE,, 24/7! In my Pv case I am assuming 6 hours of sun, also pretty optimistic,,,EXCEPT, in the winter I might get as low as zero on a bad day,, 2 hours on an average day,,, and a full 6 on a great day, plus a cold weather/reflection bonus). In the summer however,, because of my latitude,, I get as many as 14 hours on a perfect day,, as low a 2 on a terrible day (very rare in summer when we don't get a couple hours of net sun) and an average of better than 8.

hillbilly

Re: Small windpower a scam ? Survey says SO

I think that I am like a lot of folks (including Tony) who would love a small sized wind turbine, at a reasonable price of course, for just a tiny bit of extra "power diversity". I am always a fan of having backup's, and redundancies, particularly for important stuff. I think my two biggest reasons for not getting on yet are: not enough consistent winds at my site, and two, the whole idea of having a turbine with moving parts in such a harsh environment just screams "unreliable".
Obviously in the right site the amount of available power could more than offset any inconvenience of having to work on the turbine every now and then. But there's the rub, and the issue with this (or any other) "test": there are so many variable issues that affect the potential success, or failure of a wind turbine, that a "standard test" just doesn't really do justice.
Let's see this test concludes that:
-small wind turbines are unreliable, and not cost effective at low wind speeds (while mounted at low elevations)...
did I miss anything?
I suppose this "test" might be good to point out to the uneducated that wind power is not such a simple, or certain thing, but I don't know that it really says much else.
Is "small" wind right for you or for me? That's a tough question to fully answer with this test in my oppinion. I totally agree with the suggestion earlier to have a professional inspect the site, and then tailor fit that assessment to each individual and their needs.

DavidinNica

Re: Small windpower a scam ? Survey says SO

I wonder which were the 3 failures(or did I miss something in the report?) and I wonder how many failure there would be at a 6 m/s wind site. Where I live there are many and they are mostly far from the grid which is atrocious and more unreliable anyway.

emsai

Re: Small windpower a scam ? Survey says SO

I built a small VAWT (2’dia x 5.5’ ht) out of PVC, and mounted it on a floating dock, 50’ out into the NE Cape Fear River. I am about 18 miles from the ocean, and regularly get a strong W, NW, SW wind up the river. The VAWT works great, particularly with the deflectors I built to channel more wind to it. (As an aside: I also have an Apricus 30-tube solar water heater, pv-powered El Sid pump, that I installed from various components. We are completely off the grid for hot water 10 months out of the year.)

I am an amateur at this (wind turbine) stuff, as will soon be obvious. I am doing this as a hobby, but don’t mind sucking up 200-600 watts (or more) from my VAWT if I can get it. I am having trouble weaving through all the BS that is out there, especially where grid tied inverters for turbines are concerned. At the moment, I am using an Ametek 30VDC (I did day I was an amateur), and was foolish enough to buy an EnviroTechs inverter. The baby Ametek fried that inverter in two days. (I got a complete refund.) I eventually want to go to an Ametek 72 or 99 VDC, but even with the little 30 VDC, I do not know what to use for a grid tie inverter. Looking at SWEA, but still seems iffy. SMA’s Windy Boy 700u seems to be a quality inverter at the range I could use. Any suggestions?

BB.

Re: Small windpower a scam ? Survey says SO

But--according to this article--Rooftop Wind is wonderful:

You will also need consider potential noise of using a rooftop wind turbine. Many people agree that vertical axis turbines are quieter than other models. As noted above, placement is key to gain the most favorable winds and efficiency. If you have a pitched roof, consider placing the wind turbine in a higher location. For flat roofs, towards the edge.

Each day, hundreds of new rooftop wind turbines are installed across the country. Wind turbine manufacturers are busier than ever, and people looking for green jobs are finding them in the wind sector of the renewable energy industry, in part because of the rapid growth. By tapping into wind power, property owners are watching their electrical meters roll backwards, allowing them to save money while doing their part to save the planet.

Amazingly, consumers that installed residential rooftop wind turbines, cut their utility bills by 50-90%. Considering the fact that prices range from $5-10,000 for most systems (before tax credits and rebates), it can pay for itself in a few years.

...

At a mere 36 inches tall, the plug-in wind appliance can generate about 40 kilowatt hours each month, that’s enough to light a home using high-efficiency bulbs, said [Inventor Chad] Maglaque. And although micro-wind is nothing new, at $400 a pop, the Jellyfish’s price and simplicity make it a fresh face in the market. [Via Worldchanging]

Sounds wonderful...

Data? we don't need no data...

-Bill

mike95490

Re: Small windpower a scam ? Survey says SO

> Rooftop Wind is wonderful

Till the vibration shakes all the nails off your rafters, and the roof falls off.
(or the sound drives you bonkers)

BB.

Re: Small windpower a scam ? Survey says SO

One of the problems with these type of "Green Articles" is that they lead to conclusions like this (link from above article, to another on wind):

Proposed: A Wind Electric Co. generator system behind my house (N side), to generate 700-1000 W per month. System will store generated electricity in batteries to be used directly by my residence. As needed, I will continue to draw power from the grid.
I am in need of financing or a grant/tax credit. System has capacity to begin generating at just 3 mph
Estimated total cost of install approx. $10,000
Note: To date, no other residence within city limits of Eugene, OR has such a system. City coordidator for building permits says I am breaking new ground. I have told city and manufacturer I am eager to be a beta test site; I will invite news media and city, county, state, others to come here to collect data and do research studies.
I sincerely want this type of project to become a reality for myself and others.

But, why not--That is exactly what the Wind Electric Company says on their website.

Our Small Wind Residential Generators are rated to produce 2K to 4K watts in a 24 hour period. Our Windmill power has a cut-in wind speed of 3 mph, making it possible to create power with little wind virtually all day and night.

9' turbine with 1,000 watts peak at 16 mph... (I guess--there are no graphs that I could find).

Not quite sure that I would drop $5-$10,000 with a company that (apparently) does not know the difference between 4 kWatt and 4 kWatt*Hours...

-Bill

jacobs

Re: Small windpower a scam ? Survey says SO

You won't believe this......Dempster, the manufacturer of water pumping windmills for over 130 years is now offering rooftop wind. See http://www.dempsterllc.com/demp_energy_main.php

Someone did a real sales job on them!

Solar Guppy

Re: Small windpower a scam ? Survey says SO

http://www.windation.com/products.htm

5kw power rating, which they also claim

"Windation Wind-catch™ patent pending technologies, enables urban-building electric systems to, generate substantial amounts of clean power -- more than any other clean electricity system."

what a crock .... I'll put my 14kw of PV already install on my roof against that spinning drum any day

jacobs

Re: Small windpower a scam ? Survey says SO

It's just like back in the 1980's when the government offered tax credits and rebates, the crooks came crawling out of the woodwork. BEWARE!