Small windpower a scam ? Survey says SO

[mike90045]

A recent test in Zeeland ( a Dutch province)
http://www.lowtechmagazine.com/2009/...t-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_n...es/de_turbines

[icarus]

Does anybody here sound surprised?

Tony

[dwh]

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]

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]

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]

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.]

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 indicates that small 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.]

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]

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

boB

[BB.]

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/KN...971%202000.jpg
http://www.lowtechmagazine.com/2008/...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