12 Small Windmills Put To the Test In Holland 510
tuna writes "A real-world test by the Dutch province of Zeeland (a very windy place) demonstrates that small windmills are a fundamentally flawed technology (PDF of tests results in Dutch, English summary). Twelve much-hyped micro wind turbines were placed in a row on an open plain. Their energy yield was measured over a period of one year (April 1, 2008 — March 31, 2009), the average wind velocity during these 12 months was 3.8 meters per second, slightly higher than average. Three windmills broke. The others recorded ridiculously low yields, in spite of the optimal conditions. It would take up to 141 small windmills to power an average American household entirely using wind energy, for a total cost of 780,000 dollars. The test results show clearly that energy return is closely tied to rotor diameter, and that the design of the windmill hardly matters."
Actually, it would take 6 windmills (Score:5, Informative)
Re:Obvious? (Score:5, Informative)
Wow, reading more I see how blatantly WRONG this summary is. There was one windmill that two of them would power a whole house. The "Energy Ball" one is the POS that takes 47 windmills, the rest are a lot better.
Slow (Score:4, Informative)
Re:Design hardly matters...? (Score:2, Informative)
Some thoughts (Score:4, Informative)
The windmills seems to have been erected very close together. This may cause them to interfere with each other through turbulence. Also, some of them did fairly good. The Skystream and the Montana doesn't seem to be a total waste of money.
Re:Obvious? (Score:4, Informative)
And it had 5 meter blades, which are way to big for the average rooftop.
Do the math (Score:5, Informative)
There are two very simple scaling laws at play here.
First off the wind power intercepted goes up as the square of the rotor length. So larger is better, a lot larger is a whole lot better. You also get the free benefit of stronger winds as you have to raise the center point as to not hit the ground.
Next the power goes up as the CUBE of the wind speed. So it really pays big to find a real windy spot.
So your basic $30,000 small, low windmill placed on your typical house are real big losers.
Re:But the electricity (Score:5, Informative)
Dutch: 6310
USA: 13,388
And they needed a study for that? (Score:5, Informative)
It's physics 101.
Capturing a larger cross-section of moving air is more efficient.
The reverse is also true (generating thrust):
Turbofan engines are more efficient at lower air-speeds than straight turbojets.
Moving a small amount of air at a higher velocity will create more wasteful eddies than moving a larger cross-section of air at a lower speeds.
Helicopters are the extreme case WRT aircraft.
You need a lot less power to make a helicopter hover than a ducted-fan or jet VTOL aircraft (like the Harrier or the JSF).
It reminds me of people who are surprised that electric cars / hybrids take up the most energy when they accelerate.
Duh, that's when you're actually gaining kinetic energy.
In cruise, you're just fighting drag (air) and friction (road).
Re:While I agree... (Score:1, Informative)
You know what's really funny? Sailors all over the world use small wind generators to charge their batteries while at anchor.
It sounds like sea-based micro-turbines have a proven track record.
The article is bunk.
Re:Obvious? (Score:5, Informative)
windspeed cubed and radius squared
not to mention the effect of turbulance on o/p
Re:Obvious? (Score:3, Informative)
It's best to put these on a tower anyway, so that they're up above all the turbulence created by stuff on the ground. So the blades are going to be a long way from your roof whether they're 2m or 5m long (as long as you care about the machine actually generating some power, that is).
Re:A little sad. (Score:3, Informative)
You mean this [newegg.com]?
What I would like is "smart electronics" so I can push a single button on my way out and be sure I am not wasting electricity, without shutting off my fridge, alarm clock, and PVR. Maybe somebody can point me to that?
For a change could everyone read the article (Score:3, Informative)
Re:Actually, it would take 6 windmills (Score:5, Informative)
Which is also the biggest by far, 5m in diameter. The trend was very clear, despite the obfuscation with efficiency, cost and integer number of windmills all rolled into one. The bigger they are, the better they work.
Commercial 18m: 190000 / 143000 = 1.3 Euro/kWh
Montana 5m: 18508 / 2691 = 7 Euro/kWh
Skystream 3.7m: 10742 / 2109 = 5 Euro/kWh
Passaat 3.12m: 9239 / 578 = 16 Euro/kWh
And the crappiest were even smaller, though I'm not going to bother to do the math for them. In other words, none of these are worthwhile unless you absolutely can not throw up one big windmill instead of five small.
PV is more cost effective than small wind turbines (Score:3, Informative)
It's in the Netherlands (Score:5, Informative)
not in Holland. Holland is the combination of North-Holland and South-Holland, both provincies of the Netherlands. The Netherlands is the country as a whole. The Kingdom of the Netherland is the Netherlands plus the Netherland Antilles and Aruba. Zeeland(Sealand) is a provincy seperate from Holland.
Re:Actually, it would take 6 windmills (Score:2, Informative)
Note that: 6 * 2687kWh/year = 16122 kWh/year
The US average electricity consumption (2005) is 12796 kWh (source [wikipedia.org]) so you could do with about 5 Montana Wind Mills (assuming your place of residence is as windy as Zeeland).
An average Dutch resident (of let's say Zeeland) uses only 6638 kWh / year (source [wikipedia.org]) , which means that 3 Windmills should be enough.
VAWTs anyone? (Score:3, Informative)
http://www.youtube.com/watch?v=RRXRUFrxKAQ&feature=related [youtube.com]
I know that where I live, if I had one of those, I wouldn't need to be plugged into the grid (most of the time at least.)
And there are so many other hobbyists who have vawts on youtube - interesting stuff. The dutch just took the wrong approach to it
Re:Skystream returns 4% (Score:2, Informative)
Re:Design hardly matters...? (Score:5, Informative)
Clearly, designs made a huge difference in output
How the hell did this bit of poor reading comprehension get a 5 informative ranking?
Look at the size of the blades and the power produced. They are VERY proportional. Design didn't make much difference at all. What counts is the total surface area of wind you are taking advantage of. i.e. blade size.
The smallest unit had about 1/25 of the blade area coverage as the largest one, and produced fairly close to 1/25 of it's power.
Take home messages:
1) Design doesn't matter.
2) You are going to get ballpark 10 watts/square meter of wind in a windy area (avg 3.8 meters/sec wind)
4) A smaller number of large windmills are more cost effective to buy then a bunch of tiny windmills with the same surface area.
Re:It's in the Netherlands (Score:5, Informative)
Also, because people often ask the question of people from New Zealand; yes there is an 'Old Zealand', and this is it.
Re:EPA would never let you build them (Score:4, Informative)
Producing Transportation Fuels with Less Work
Diane Hildebrandt,1 David Glasser,1 Brendon Hausberger,1 Bilal Patel,1 Benjamin J. Glasser2
The long-term strategy for reducing emissions of carbon dioxide (CO2) and other greenhouse gases is to replace fossil fuels with renewable resources. In the short term, liquids derived from fossil resources will be used to power transportation, in part because liquid fuels have an established production and delivery infrastructure as well as high energy density. Liquid fuels are overwhelmingly derived from increasingly scarce crude oil, and it would thus be beneficial to make liquid fuels from other sources, such as coal and biomass (1, 2).
One reason why liquid transportation fuels are derived from petroleum instead of coal is that converting coal into liquids is much more energy-intensive. Thus, substantially less CO2 is released in the production of a gallon of gasoline derived from petroleum than in the production of fuel from coal-to-liquids (CTL) processes (1). The carbon atoms in coal are largely bonded to one another in graphitic networks, and breaking these bonds requires a large energy input. Energy is also needed to supply hydrogen to the process. We outline reaction chemistry and processing designs that could dramatically reduce these energy inputs and minimize the amount of CO2 emissions that would be emitted or mitigated by other costly strategies, such as carbon capture and sequestration (3).
There are many methods that convert carbon-rich sources into liquid fuels, including pyrolysis, direct liquefaction, and indirect liquefaction, which proceeds through gasification such as the Fischer-Tropsch (FT) and methanol-to-olefins (MTO) processes (2, 4). Of these, the FT process
3C + 4H2O -> 2CO + 4H2 + CO2 -> 2(-CH2-) + 2H2O + CO (1)
(where CO is carbon monoxide and -CH2- represents the alkane products) has been successfully implemented on the largest scale industrially (2, 5) but is very inefficient in that a large part of the carbon fed into the process ends up as CO2, either directly or indirectly from fuel consumption for heating the reaction (5). However, FT technology gasifies the coal so that unwanted ash, heavy metals, and sulfur can be removed (2).
To identify more efficient ways to run chemical processes, theoretical tools have been developed that can look at the industrial plant as a whole (6-9), even at the level of rethinking the reaction chemistry. These tools assess what would happen if we could operate the plant as efficiently as possible (that is, near thermodynamic reversibility).
For example, thermodynamic principles have been applied to examine the production of molecular hydrogen (H2) by thermochemical cycles (6). By analyzing reversible processes, limits can be placed on the best performance that can be achieved for a given cycle. For example, H2 could be produced through chemical reactions powered directly by the heat from a nuclear reactor, such as zinc reacting with water to produce zinc oxide and H2. The zinc is recovered by heat-driven decomposition of zinc oxide. A thermodynamic analysis has shown that the currently proposed thermochemical cycles for producing H2 cannot compete with electrolysis of water through direct use of electricity (6).
Thermodynamic analysis of reversible processes can be coupled with theoretical efficiencies to allow comparison of real processes. Such an analysis was performed for direct H2 use for transportation, and the findings were compared with other strategies for reducing greenhouse emissions and U.S. oil imports (6, 10). This work has brought to light serious concerns about the feasibility of an H2 economy.
However, recent work suggests a path forward for the sustainable production of liquid hydrocarbon fuel for transportation that would make use of H2 produced from carbon-free energy, such as solar or wind (1, 11). These processes add H2 to the syngas (CO and H2) produced from gasification of biomass, a
Re:But the electricity (Score:4, Informative)
www.allianceforwaterefficiency.org/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=2538
Source being the IEA. The figures are based on 1998 data.
Re:Some thoughts (Score:4, Informative)
No. The 72 TW figure represents only "global wind power generated at locations with mean annual wind speeds 6.9 m/s at 80 m [altitude]". [stanford.edu]
No. You're an order of magnitude off. Global consumption of electric power is about 1.6-1.8TW (same source as above).
According to the researchers behind the 72TW figure, if we could catch 20% of the wind power at the good locations, "it could satisfy 100% of the world's energy demand for all purposes (6995-10177 Mtoe) and over seven times the world's electricity needs".
The idea that you'd spread such FUD about wind power is embarrassing.
Re:A little sad. (Score:5, Informative)
bigger houses in USA = more air to heat/cool
I think there are a lot more gas ranges/water heaters in Europe
I think front load washing machines are much more common in Europe
Let's not forget the stereotypical smelly Frenchman, it is perfectly possible to have first-world societies where everyone doesn't shower each and every day.
Just a comment but from what I see on the TV renovation shows, every window in California is single-pane and insulation is a liberal myth. In Canada you'd freeze to death, in Cali apparently you just crank the AC a little higher and wonder why the power bill is so high.
Re:Actually, it would take 6 windmills (Score:1, Informative)
Those numbers are from the 1 year test, so they're for actual production in an area with less than optimal wind, not theoretical capacity. 5 EUR/kWH (divided by the lifetime in years) is attractive if you're far from the next power line and would have to pay for a long branch line.
Re:Obvious? (Score:3, Informative)
Re:De-facto benchmark (Score:5, Informative)
Sure, we're not all US, but US households are becoming a de-facto benchmark because they're the biggest consumers of energy on a per-household (or per-capita) basis.
Actually they are not. In Canada we have a bigger household energy consumption than the US but this is due to heating. When it the winter lasts 6 months and temperatures drop to -40C heating tends to use a lot of energy no matter how efficient your home's insultation is.
That depends (Score:2, Informative)
When did you sell your tulips [stock-market-crash.net]?
Re:Actually, it would take 6 windmills (Score:2, Informative)
Price per kwh (Score:2, Informative)
Without discounting to present value or accounting for inflation or other possible future taxes, you need 18 years of flawless operation to break even.
Finding this amusing (Score:5, Informative)
Having grown up in a household whose total electrical needs were powered by a single 3m wind generator, I'm finding this article summary awfully amusing.
Re:Slow (Score:3, Informative)
Your argument is actually way off, 3.8 m/s is rather windy...
Err... no. My argument is not that "3.8 m/s is not very windy" (although it's not). My argument is "3.8 m/s is well known to be far below the acceptable level of wind required for wind power."
With regard to the first point, as others have pointed out here, 3.8 m/s is Beaufort force 3, which is technically known as a "gentle breeze", and spans the range of 7 to 10 knots. While you can have a nice day on the water under those conditions, it is not in any sailor's estimation "rather windy".
But more importantly, as I said clearly before: everyone who knows anything about wind power knows that winds of less than 5 m/s aren't really worth talking about with regard to wind power. Ergo, this study is exactly as I described it: a test of the viability of wind power at wind speeds that everyone who knows anything about wind power knows are too low to be viable.
The result is therefore entirely unsurprising. If there are people arguing that 3.8 m/s is sufficient for a viable wind power installation at any scale, do please link to them--the installations I'm familiar with in Ontario have average wind speeds in the 6.5 to 7.5 m/s range.
I agree that 100 m is far higher than most micro-windmill installations, but that's the installer's problem. If I were to install a micro-windmill it would have to be that high to get decent wind, and that's a viable critique. If the study had said, "Micro-windmills are routinely installed on towers so short that they can't get enough wind to be worthwhile" that would be one thing, but instead for some reason the study picks a wind speed that, again, is KNOWN to be inadequate, and demonstrates that what we already know is true.
Re:Obvious? (Score:5, Informative)
But what sort of idiot puts a windmill on a roof? There are so many things wrong with that.
1) A roof is way too low. The optimum height, in terms of tower cost versus power value, for a turbine of scale sufficient to power a household is generally at least a hundred feet, and preferably notably more. Wind roughly follows a so-called "1/7ths power law", so those first hundred or two feet up make a huge difference. After that, it's a case of diminishing returns.
2) A roof is high turbulence. Turbulence is very bad for wind turbines -- robs them of powers and stresses their hardware. You want to be well above sources of turbulence.
3) A roof is generally not nearly strong enough, and would have to be reinforced anyway.
4) They weren't even bothering to test on a roof in their study.
One thing this article left out was the tower. That may seem like a trivial thing to most people here, but it's not in the least. I made a spreadsheet to crunch the numbers when I was looking into wind power. I found that it actually can be approximately breakeven where I live (in Iowa) if you're out in the countryside so that you can build a very tall tower, and you use a guyed tower**, and you can get a good deal on the tower, and you're grid connected so you don't have to deal with power storage, and you're not an idiot when it comes to turbine selection. Yeah, a lot of "Ifs". But regardless, the tower generally makes up 50-75% of your total costs in a properly designed home-scale system (20-25%-ish on a commercial-scale system).
Re:Finding this amusing (Score:5, Informative)
Sure, if you'll make an effort to restrain your incredulity and be a little more polite.
Propane stove and fridge. 1500 kg lead-acid battery bank. About 15 12v incandescent bulbs ranging from 40w to 100w. Computer on an antique and inefficient square-wave inverter, small b&w TV, two stereos, and occasional power-tool usage. The only hard part is the fridge. Propane fridges really suck, or they did in the 70s.
Apart from that, it's pretty easy if you're willing to live small. Not everyone wants to live like a USian with a strong urge to max out their credit cards on electronics and appliances.
Re:While I agree... (Score:3, Informative)
Re:Skystream design better? (Score:3, Informative)
IIRC, power output increase as the cube of windspeed and the square of surface area. Might have those mixed up. But in either case, no, power output does not scale linearly.
-b
Re:Design? (Score:2, Informative)
Re:Actually, it would take 6 windmills (Score:3, Informative)
Commercial 18m
currently, windmills of 2Mw are being installed everywhere. those have 80m diameter, So that 18m one is a very small one.
Re:Some thoughts (Score:4, Informative)
With uranium mining you have to process a lot rock to get a little uranium, that is, it takes a lot of *energy* to get the ore in the first place. To put it in perspective extraction takes 2.4 gigajoules per ton for soft ores and 5.5 gigajoules per ton for hard hard ores. To get a kilogram of uranium you have to process 500 tons of hard ore because there is almost no soft ore left. These estimates assume an extremely optimistic extraction efficiency (approaching %50) and assumes you have a high grade ore. Even then you still have to factor the energetic remediation of the mine tailing. If we are to compare nuclear to wind, these are factors that have to be considered when taking about Uranium mining.
If you are going to have a huge energy expenditure just *extracting* the fuel from the ocean, why not just extract the thermal energy from the ocean itself?
Today no-one can make any claims or any comparison between the energy efficiency of those two processes (or if there is an energy return) because both are still theory and not a measurable industrial activities. Sure it might be possible to extract wave energy to extract the uranium from the vast volumes of water you would have to process but you still don't know if it will produce a net energy deficit. Eventually you end up in the position where you could convert the wave motion (or use the extraction process energy) directly for consumption.
Re:And they needed a study for that? (Score:3, Informative)
Trust me, the air being forced downwards is the only thing keeping a helicopter (or any aircraft) in the air. Or rather, don't just trust me, trust NASA [nasa.gov] (you can even check their working [nasa.gov]).
Where did they find so expensive turbines? (Score:2, Informative)
The cheapest turbine they have is 4300 euros. This is ridiculously high price. In Finland, you get a 2.1m diameter rotor for less than 1000 euros (controller, mast, turbine), and a full kits with batteries, inverter and solar panels for 1400-2500 euros. A 3.2m diameter turbine here costs around 4000 euros and 8m diameter turbine around 20k-30k depending on configuration. These are list consumer prices including taxes. The prices quoted in the Dutch "test" seem to around 4 times what you pay here!
The quoted average wind of 3.8m/s seems inland wind speed. It is quite obvious that there is no point in installing turbines in locations where the average wind speed is low, but they seem to get some power from the larger turbines, though the price level they have kills the payback times.
They correctly point out that taller mast makes a difference, but one point for large industrial turbines is ignored - industrial turbines do need a grid to deliver the energy. For small turbines, the idea is to use the energy where it is produced, avoiding cost of grid. Grid cost in Finland is around half of the the bill, and taxes around 30%. We have grid/transmission cost separately priced so you can select to buy renewable-only energy from grid).
They did figure out, which I assume most people in industry already know, that the diameter is the interesting factor. The power generated is in relative to diameter and square of wind speed and efficiency factor. There are lots of snake oil companies out there claiming bogus production numbers, which is unfortunate as it spoils the reputation of good idea. There can be easily spotted by calculating a wind area covered by the turbine and dividing that by price. As getting efficiency up by few percent tends to be very expensive, it is easier to just make simple blades few percent longer. The cheapest wind turbines sold here have continuous profile blades, and they still perform nicely, even though the center part of the turbine probably does not do much work.
We have 2.7m diameter unit (www.tuulivoimala.com [tuulivoimala.com], 500W nominal) at our vacation home we use in summertime. This is very non-optimal location, only northern winds and too much shadow for solar, so we took more diameter and big battery pack to offset non-windy periods. We use the power for lights, computers, 3g WLAN access point for network. Total cost of all electrical installation including lights, wiring, 2kW inverter, 980Ah battery pack, was less than getting grid to the place. Not enough for heating, but we burn wood for that, the plot is large enough to provide us practically unlimited supply of firewood. The power has been plentiful for our use. Electric chainsaw works for chopping the firewood, though we need to avoid continuously sawing more than 1 hour to avoid emptying the battery pack more than third :)
If you do not have a grid connection, the install cost of it will offset quite a big turbine and solar installation, so small turbines are very popular in vacation homes. And for vacation home, the more remote the better. Which means very expensive or impossible grid connectivity. In Scandinavia, solar does not work early spring or late fall, so wind turbine here may be the only option if you need electricity off-summer times. Combining solar and small wind turbine makes a lot of sense as the electrical installation is similar.
The same thing applies to developing countries. It often makes more sense to go directly to renewables than build grid to every small village. In south solar power or hybrid solar-wind is probably more dominant.
They claim that turbine does not even make up the energy used in making it. This is true only if the turbine is located in a low-wind location, or it is faulty design (no diameter!). I agree fully that it does not make sense to install turbines in city areas where buildings mess up wind flows. The location has to be one with good wind conditions.
To
wrong wind speed (Score:3, Informative)
The reported average wind speed seems rather slow, for that area. The average wind speed is normally more like 6 m/s. Here' s a wind speed map of the Netherlands: http://www.gewiekste.nl/wdk.jpg [gewiekste.nl].
Re:It's in the Netherlands (Score:1, Informative)
As a Dutchman myself, I can safely say that no-one uses your definition anymore, and it hasnt been used that way by the common populace for at least 100 years. Holland = The Netherlands. They are interchangable. And no, The Netherlands do NOT include Belgium or Luxemburg. Thats the BeNeLux.
And yes. I took all those words just to point out you were being pedantic.
Re:Slow (Score:3, Informative)
Now, officially, wind speed must be measured on a pole of 10 meter height. In Ontario that would also be < 5 m/s looking at your link. I think that is what the study is talking about.
If you look here: http://www.windmolensite.be/pics/europa_windmap.jpg [windmolensite.be] you see that at 50 meters zeeland is already 5-6 m/s, one of the best you find in Europe
Re:While I agree... (Score:3, Informative)
Not paranoid enough.
A friend of mine had a hacker friend who got a job testing security at nuclear plants.
He found so many security flaws that the managers posted his picture and said, "Please help our new security tester".
Among the flaws.
* A "man trap" which he easily climbed out of.
* People who let him in to secure areas when he said "Just a second- hold the door"
* Secure areas with only partial concrete/steel walls (the rest of the surrounding area was sheetrock)
* trivial passwords
* Passwords on sticky notes
The impact of a nuclear terrorist attack could be catastrophic. It's like the financial derivatives- the downside was unlikely- but the consequences were horrific.
If folks found a way to attack America, China, or Russia through Uruguay nuclear power plants, then an attack will happen.
I'm not sure it is paranoia when you've been attacked multiple times
Re:Finding this amusing (Score:3, Informative)
That's what my grandparents did. And they never had a problem with the propane fridge. Only they managed on a couple car batteries and a small solar panel. And they had a small and large gas generator for when needed (the large one for power tools, the small one for occasional needs).