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12 Small Windmills Put To the Test In Holland
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."
rather than 141, if you used the Montana.
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.
3.8 meters/second average is not a windy area, infact it's a Class 1 wind speed. There are many places in the U.S. that are Class 3 or better, and you'd get much different results from those areas.
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.
GAAH! MY PRINTER IS ON FIRE!!! PUT IT OUT! PUT IT OUT!
And it had 5 meter blades, which are way to big for the average rooftop.
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.
I was curious (in kWh):
Dutch: 6310
USA: 13,388
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).
windspeed cubed and radius squared
not to mention the effect of turbulance on o/p
This has to be the worst summary ever. Please take the time to look at the article and do the maths yourself.
"Some days even my lucky rocketship underpants don't help."
On the Renewable Energy website OliNo there is an article Test results small wind turbines website with some more background on this test. The first test results show that a PV system (Solar Energy) is more cost effective than these small windturbines. The Dutch article, which is more up-to-date, show also the last measurement results of the windturbines (11 months of data). The conclusion is the same. However, it was found out, that an official wind measurement station of the KNMI only 14 kilometers (8.8 miles) away form the test site has an average windspeed which is twice of of the test field. This could explain the low yield of the windturbines.
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.
Knowledge is power. Knowledge shared is power lost.
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.
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
Sorry, how rude of me.
www.allianceforwaterefficiency.org/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=2538
Source being the IEA. The figures are based on 1998 data.
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.
2 to power an average Dutch home, an American home takes on average 3 times more energy. Important bit in TFA: the 18-meter windmill nearby only cost about 20% more than the combined cost of all the small windmills, yet it produces 20 TIMES the power.
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.
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.
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).
"You see, Government is a system that is based on weapons." -- Timster