Forum: Author Hangout

American windmills are mostly to pump water. You don't need much power to do that. But a windmill to grind wheat and make flour need to turn a heavy stone and that requires a lot of power so you need wide blades and a sturdy building to hold it up (and contain the mill).

Exactly correct. Though it is not just the power needed to turn the milling stone(s). Speed control is just as important. As the wind gusts, the solution was to have movable panels in each sail, these could be moved relative to the wind which increased or reduced the surface area and thus the speed of the sails as they revolved. This kept the milling stones turning at optimum speed.

not the little water a US mill pumps to fill a trough with water for cattle.

Actually, for the most part those US windmills didn't just fill a single trough with water. Generally, the pump ground water up to a small wooden water tower which then has gravity feeds to supply water to the entire farm.

Actually, for the most part those US windmills didn't just fill a single trough with water. Generally, the pump ground water up to a small wooden water tower which then has gravity feeds to supply water to the entire farm.

I didn't know that. I know our Dutch wind mills but what I know of the US mills is just what I saw in western movies, those of the pole type in the middle of nowhere ;)

A simple answer to this topic would be to correctly identify Dutch windmills verses US Windpumps. The windmill actually has a milling operation in the base. These contain a hoist system to lift the grain up to a hopper where it trickles down via gravity onto a rotating mill stone and ground into flour.

In the Netherlands there are more classic windmills for displacing water than for milling grain. In some cases multiple mills in a row. They still look and work the same, it's just that the generated power is used differently.
This site is in Dutch but the pictures show exactly what I mean: Dutch windmills

There are classical dutch style windmills in the US, most are on (or were originally built) on the eastern seaboard in the 18th and early 19th centuries, and some remained in use as late as the 1930s.

The are even two in San Fransisco that are/were used to drain one of the major parks.

There are classical dutch style windmills in the US, most are on (or were originally built) on the eastern seaboard in the 18th and early 19th centuries, and some remained in use as late as the 1930s.

The Dutch played a major part in the first creation of the US. For example what is now New York (city) was founded by the Dutch as New Amsterdam and only later became New York. So it's only natural that Dutch 'technology' was also used to build in the old USA. Those windmills were build to last a long time and had to be very strong to cope with the enormous power of wind and water. Alas, like the saying goes, they don't build anything like that anymore, it's for the short term profits nowadays. The currently build windmills for electricity will not even last a tenth of the time the old windmills will stand proud.

The currently build windmills for electricity will not even last a tenth of the time the old windmills will stand proud.

Some of them won't last, but many will. Maintenance is the key to anything that last.

Some of them won't last, but many will. Maintenance is the key to anything that last.

Very, very few of them will last.

1. if wind speeds get too high, they will self destruct.
https://www.youtube.com/watch?v=hcwBSzW4t64

2. Maintaining Grid Scale wind turbines is more expensive relative to nameplate capacity than any other form of electric generation. Maintenance crews have to be delivered to / removed from the nacelle by helicopter. The vast majority of wind farms seriously neglect preventive maintenance due to the cost and once they fail, they tend to fail somewhat spectacularly and are almost always a total loss.

Some of them won't last, but many will. Maintenance is the key to anything that last.

Best maintenance can't prevent failure if it's not designed to last. E.g. poor material quality, plain wrong choice of material, too small dimensioned to withstand stressing forces, ...
I remember one case of an injection lance made of best stainless steel designed to inject sulfuric acid into a thick stainless steel pipe tranporting hot salted water to the pump. The lance was welted into the pipe. The company that did the construction had to replace the lance three times within the first year, then they finally used HASTELLOY instead of stainless steel and no more corroding happened.

HM.

Best maintenance can't prevent failure if it's not designed to last. E.g. poor material quality, plain wrong choice of material, too small dimensioned to withstand stressing forces,

Wind turbines are already the most expensive way to generate electricity on a per megawatt hour basis. There are no materials to make them from that are strong enough to stand against gale force winds without making them non-functional.

If you simply made the wings from thicker steel, You would have to make the nacelle and tower from thicker steel as well just to hold the extra weight.

And by the time the wings were thick enough to stand up to gale force winds, the wings would likely become so heavy that they wouldn't turn at all under normal wind speeds.

Some of them won't last, but many will. Maintenance is the key to anything that last.

Others already made points against that statement. For me, one look at the fragile structure is enough to be convinced that they won't last as long as the hundred+ years the classic windmills survived.

For me, one look at the fragile structure is enough to be convinced that they won't last as long as the hundred+ years the classic windmills survived.

They won't last a tenth of that, at least not in a functional sense. A few may fail with out a total collapse. The productive lifespan of a grid scale wind turbine in practice is 12-15 years, And that's not counting failures due to extreme weather.

https://www.telegraph.co.uk/news/earth/energy/windpower/9770837/Wind-farm-turbines-wear-sooner-than-expected-says-study.html

The productive lifespan of a grid scale wind turbine in practice is 12-15 years, And that's not counting failures due to extreme weather

https://www.telegraph.co.uk/news/earth/energy/windpower/9770837/Wind-farm-turbines-wear-sooner-than-expected-says-study.html

That number is based on that report. A report that you should really look into before quoting it.

Others already made points against that statement. For me, one look at the fragile structure is enough to be convinced that they won't last as long as the hundred+ years the classic windmills survived.

So by look alone you judge them weak. Interesting failure analysis there. Your 'classic' windmills would be a inoperable if not a pile of rubble inside one hundred years without maintenance.

It's called mechanical engineering. If that is sound, it will last hundreds of years 'with' proper maintenance.

It's called mechanical engineering. If that is sound, it will last hundreds of years 'with' proper maintenance.

Modern gird scale wind turbines mostly doen't get proper maintenance, it's simply too expensive/dangerous vs the value of the electricity they produce.

There's a whole industry simply doing support for them here - we've more than 700 turbines in the state.

Where is here?

Where I am and in several other areas in the US, you can drive past any wind farm and anywhere from 1/3 to 1/2 of the turbines aren't turning, there are entire wind farms that were simply abandoned by the operators, because maintenance costs exceeded their revenues. Wind farm operators who have gone bankrupt and there is no one to cover the cost of removing the failed turbines.

What do I consider proper maintenance? How about any maintenance at all?

In the US, there are companies that built wind farms not to try and profit from the sale of the electricity, but to collect government subsides. They did no maintenance on the turbines at all. Simply collected what they could in subsides until the turbines started to fail. Then they either filed for bankruptcy or vanished, leaving someone else with the cost of dealing with the failed turbines. Some of these wind farms lasted less than a year.

In the US, there are companies that built wind farms not to try and profit from the sale of the electricity, but to collect government subsides. They did no maintenance on the turbines at all. Simply collected what they could in subsides until the turbines started to fail. Then they either filed for bankruptcy or vanished, leaving someone else with the cost of dealing with the failed turbines. Some of these wind farms lasted less than a year.

Unfortunately that does and has happened. It's going to happen to anything substantially subsidized by the government. Wind energy is not alone in that either. It's happened in oil, solar, nuclear energies among other things. If it were a matter of sustaining profitability through production, those fields left abandoned would still be running and receiving proper PM. In fact, the megalithic versions would have never been put up to begin with.
A proper design would account for PM needs, with an emphasis on longer service life. I am aware of some that were never built with that in mind.

That however, doesn't mean they could not stand the test of time if properly designed and maintained. Proper design, maintenance, and profitability are not mutually exclusive either.

That however, doesn't mean they could not stand the test of time if properly designed and maintained. Proper design, maintenance, and profitability are not mutually exclusive either.

Profitablity is mutually exclusive with grid scale wind power.

1. wind is intermittent, sometimes it doesn't blow, sometimes it blows too hard.

2. Because of the intermittency, if your customer base is used to a 24/7 reliable power grid, you need 100% backup from nuclear or fossil fuel sources. In the US the largely means coal or nuclear. But Coal and nuclear are designed for base load, the are all on or all off. A coal plant takes days to cold start, a nuclear plant takes weeks. This means to act a backup for a wind farm, they have to be kept hot and the turbines running at full speed even if no electricity is being supplied to the grid.

3. Grid scale wind is more capital intensive than even nuclear. Mostly because of land. An 1800 MW nuclear plant requires around 1,100 acres of land. A similar capacity coal plant would be around the same footprint.

Grid scale wind on the other hand requires 60 acres per MW of name plate capacity, or 108,000 acres (169 square miles) for a name plate capacity of 1800 MW. Two orders of magnitude more land than coal or nuclear for the same capacity.

Then you have to account for the Capacity Factor. CF is actual production over time / NP capacity * the same time interval. Average annual CF for US coal plants is around 50%, Nuclear is 90% (and individual well maintained and operated Nuclear plants can run at 100% CF for up to 18 months), Grid scale win CF is only 30%

4. Maintenance costs for grid scale wind will always be significantly higher than for other fuel sources, because of the land area issue + number of moving parts

For the 1800 MW nuclear plant mentioned above, that's 3-5 reactors, 3-5 steam turbines, and 3-5 generators.

On the other hand, for a single wind turbine you have the electric generator, a transmission gear box to transfer rotational power from the rotor to the generator, the rotor itself, the angle of each individual blade of the wind turbine needs to be adjustable for different wind speeds, the Nacelle that houses all the other moving parts has to be able to rotate to keep the rotor assembly facing into the wind. so significantly more moving parts (even if they are smaller). The most common size grid scale wind turbine in the US is around 2.5 MW the largest available are still under 6 MW.

To match the total capacity of the 1800 MW nuke plant, you will need 720 2.5 MW turbines or a little over 300 of the largest turbines available, spread over a minimum of just under 170 square miles.

The only ones making money on this deal absent relatively massive subsidies are the people manufacturing the turbines.

5. Without profits, PM is the first thing that will get cut (or ignored all together) to cut costs.

I would suggest checking up on the VC Summer project before arguing cost.

I'm guessing you work or have worked N. Anna, Surry, etc. Most likely the former.

I get it, you don't like wind. So you know, my inspections and name are all over the replacement heads. I'm not against nuclear or better forms of fossil. Like everything else, all things in moderation with thought.

However, I consider it bone headed to summarily dismiss any form of energy.

I'm guessing you work or have worked N. Anna, Surry, etc. Most likely the former.

Why? No, neither. I live in Wisconsin and always have. I have worked for Commonwealth Edison in Illinois.

So you know, my inspections and name are all over the replacement heads.

How on earth could I possibly know that? And why should I take your word for it?

I consider it bone headed to summarily dismiss any form of energy.

I don't dismiss wind power, it has it's place, very useful at small scales isolated from a power grid. It does not and never will have a significant place at utility / grid scale.

Why? No, neither. I live in Wisconsin and always have. I have worked for Commonwealth Edison in Illinois.

How on earth could I possibly know that? And why should I take your word for it?

Doesn't matter if you take my word for it or not. You've just made it clear you know of what I was speaking.

At every turn, you've made it crystal clear you don't believe it's viable. You've yet to put up any evidence that it's not.

Your opinion is your own, I do not agree with it as a blanket indictment of wind power. We will not agree here, so I'll leave it be.

You've just made it clear you know of what I was speaking.

No, I don't, or at least I didn't until you mentioned it in this thread. I've never been in the area you mention.

Where do you come up with that number?

http://www.entergy-arkansas.com/content/news/docs/AR_Nuclear_One_Land_Use.pdf

The average turbine here (and since you wondered where here is, even though I've said it many times on the forum - Oklahoma) is 1.5MW nameplate capacity, and has a ground footprint of 1 acre per turbine.

Is that just the actual footprint of the turbine? or are you counting the required spacing between turbines?

Since the earliest turbines were built, they have learned each turbine will create a cone of turbulence in the wind that will reduce the effectiveness of any other turbine in it's wake.

https://www.planningni.gov.uk/index/policy/planning_statements_and_supplementary_planning_guidance/pps18/pps18_annex1/pps18_annex1_wind/pps18_annex1_technology/pps18_annex1_spacing.htm

Wind turbines need to be positioned so that the distances between them are between 3-10 rotor diameters (about 180-600 metres for a wind farm using 60m diameter, 1.3MW wind turbines) depending on the individual circumstances of the site. This spacing represents a compromise between compactness, which minimises capital cost, and the need for adequate separations to lessen energy loss through wind shadowing from upstream machines.

A circle with a radius of a 180m to 600m would cover 25 to 300 acres and that's just for one turbine.

For the 1.5MW turbines you mention, they would have a rotor diameter of 100M

The minimum recommended spacing from the document above would give an effective turbine foot print of 70 acres.
https://en.wind-turbine-models.com/turbines/640-lagerwey-l100-1.5-mw

What you don't say, though, is that doesn't mean the rest of the land within the wind farm other than the single acre where each of the turbines sit is still perfectly usable.

Not perfectly, it may still be usable for some things, but not everything.

There are safety issues with having people living too close, And I am not talking about the strobe and noise effects either. I've read about cases from the UK where blade fragments from turbines that failed catastrophically struck occupied homes, in some cases, as much as a mile away from the turbine.

As of 2017, Oklahoma was number 2 in wind power generation, with 7,500 MW generated, behind Texas, which generates more than 22,500 MW. Even if they were all 1 MW turbines (which they're not, most are 1.4 - 1.8MW), that's only 30,000 acres (12,140 hectares).

Sorry, those numbers are not impressive.

Grid scale wind generated just 6.3% of US electricity in 2017

So by look alone you judge them weak.

I judge them too weak for purpose based on the vast numbers of videos available on the internet of wind turbines self destructing and/or being torn apart by high winds.

I judge them too weak for purpose based on the vast numbers of videos available on the internet of wind turbines self destructing and/or being torn apart by high winds.

They should cut down all the trees anywhere near the turbines...

After all, if the trees didn't sway around so violently, there would be no high winds...

I judge them too weak for purpose based on the vast numbers of videos available on the internet of wind turbines self destructing and/or being torn apart by high winds.

As I said before, there are some that wouldn't make it. The megalithic versions you're speaking of are among them.

However, all the failure videos added to the text reported, do not even touch upon the number of towers in existence today. Nor does any video typically account for 'why' they failed. For that, there are three main categories;

1. Poor or no maintenance.

2. Poor design/engineering.

3. Poor initial construction.

Any one or combination will bring down any structure you care to mention.

The megalithic versions I count in with poor design. Most of them are simply scaled up versions of smaller successful designs. I know of some companies that did that with no additional stress calculations, modeling, or testing. Those were doomed before they were ever erected. YouTube gurus abound, actual engineering analysis, not so much.

An example of poor design and construction can be found in the north sea fields.

http://notrickszone.com/2018/04/27/massive-damage-large-scale-engineering-debacle-threatens-as-north-sea-wind-turbine-breaks-apart/

That story is an example of all three combined. If it were taken by itself, it would paint a picture of world wide catastrophe for wind power. However just like taking youtube videos as a sign with no further research or engineering analysis, it leads to an entirely wrong conclusion.

You are of course entitled to your opinion however in error in may be.

The megalithic versions I count in with poor design. Most of them are simply scaled up versions of smaller successful designs.

I don't disagree that wind turbines work well on a small (residential) scale, particularly in areas isolated from power grid access. Even for the small scale turbines, I don't think survival of the turbines for hundreds of years is possible. No level of maintenance will completely prevent corrosion in steel left out in the elements all the time. Eventually it will reach the point of being uneconomical to repair. and it likely wouldn't even take a decade of neglect to reach that point.

The megalithic versions I count in with poor design. Most of them are simply scaled up versions of smaller successful designs.

For grid scale turbines, I don't think it's just a matter of poor design. I do not believe we have access to materials that would be both light enough for such a turbine to function in low winds while being strong enough to survive in high winds without locking down the rotor so it can't turn and therefore can't function.

it would paint a picture of world wide catastrophe for wind power.

Grid scale wind power is a catastrophe.

You are of course entitled to your opinion however in error in may be.

I might reconsider if you could point to what you would consider an adequate design for grid scale wind power that would be remotely feasible to build.

https://www.vestas.com/

Check with them for grid scale.

No level of maintenance will completely prevent corrosion in steel left out in the elements all the time.

As for steel corrosion, there are multiple examples of steel construction in existence today that have well exceeded the 100 year mark. You're not looking if you can't find one.

To get you started, look up the (edit for US example) Brooklyn Bridge.

So by look alone you judge them weak. Interesting failure analysis there. Your 'classic' windmills would be a inoperable if not a pile of rubble inside one hundred years without maintenance.

A small high tower is always vulnerable. Add in the wide wings and the enormous stresses on that small tower and you don't have to be a genius to conclude that it works but will not last without extensive maintenance and control. The classic windmills can't generate the same amount of power but they were build to last and withstand the powers the wind puts on them with very little maintenance. Only some parts have to be replace due to heavy use, which parts differ with the type of mill.
There's one more use that very few people know about: mills were used to signal messages by putting the wings in a certain position, differ the sails and their position on the wings and adding flags to the tips of the wings: Mill messages
Translation: row 1: happiness, mourning, temporarily out of order. row 2: long time no work, request to come as fast as possible, wedding celebration (mostly in the province of Friesland). Wing messages differed per province.

A small high tower

Exactly what is a small high tower? It cannot be a small tower if it's high.

As for stresses, please define which stresses your speaking of? Which one do you consider most detrimental and why?

Exactly what is a small high tower? It cannot be a small tower if it's high.

Have you never bought your own suit? Trousers? Jacket?

If you have you will have noticed the sizing includes short and long versions.

Maybe he is measuring his tower as would a tall guy with short legs...?

Please note that English is not Keet's first language.

I'm aware of that. It's why I asked this question.

Exactly what is a small high tower?

Exactly what is a small high tower?

Narrow and tall. Just watch a flag pole when the wind is blowing. Even without a flag attached it will bend. That will not happen with a short, wide, and heavy construction.

Narrow and tall. Just watch a flag pole when the wind is blowing. Even without a flag attached it will bend. That will not happen with a short, wide, and heavy construction.

How many flag poles have you seen blown down of any size? A small diameter to height ratio doesn't mean a lot with proper engineering.

https://warwick.ac.uk/fac/sci/wmg/globalcontent/courses/ebm/mant/materials/properties_of_materials/
That is some basic background. Take it with the following:
https://www.teachengineering.org/lessons/view/wpi_lesson_1

I'm assuming you are unaware of which stresses are more harmful given your answer. With a tower, it starts at torsional, then there is tensile and compression. There are others, but those are the three of primary concern. Shear comes into it as well, but mostly for mounting hardware.

Poor engineering (read cheap usually) usually involves using poor steel and insufficient thickness for the towers. For the blades, it's all over the place, but if they are fiber, failure is usually sourced in improper bonding during construction.

Bottom line is, proper engineering and maintenance are the keys.

Bottom line is, proper engineering and maintenance are the keys.

Which would make a reasonably durable construction more expensive than it's weight in gold. Let's face it, they are build for the subsidizing money, not to create clean energy. They are designed for short term maximum energy delivery and then left to die.

Exactly what is a small high tower?

Narrow and tall. Just watch a flag pole when the wind is blowing. Even without a flag attached it will bend. That will not happen with a short, wide, and heavy construction.

I don't think that's what it means with a wind turbine.

Men's pants are sized primarily by waist circumference, and secondarily by inseam (leg height).

Similarly, Wind turbines are sized primarily by by the radius of the circle that is created by the motion of the blades when turning (this is almost entirely determined by the desired name plate capcity), and secondarily by the height of the tower.

A small turbine on low ground might be put on a higher tower to catch smother/stronger winds while a large turbine might on the highest point in the area might be put on a relatively short tower that gives the blades the smallest safe ground clearance.

PS: On the flagpole issue, I've never seen a flagpole without a flag on it bend absent extreme winds (tornado/hurricane force winds) There is a good reason for this. Wind at any speed will push much harder on a flat surface than on an aerodynamic surface (like a round pole). The earliest grid scale turbines were mounted on lattice towers built using angle iron, square section steel or triangular section steel, that presented flat surfaces to wind coming from the right direction. These lattice towers would fail in high winds. Which is why the switched to round steel poles. No matter what direction the wind blows, there is no flat surface to push on.

name plate capcity

What does "name plate capacity" mean?

The designation (literally stamped or etched on plate attached to the turbine) of the momentary electric power that would be generated by the turbine under ideal conditions. In other words, the theoretical maximum amount of power than can be generated by the turbine without sustaining damage.