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Alistair_Heaton
Mechanical
That's a lot of capacity that's been lost. Must admit being Aberdonian we always associate Texas with hot and humid... Not snow storms.
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Texas power issues. Windfarms getting iced up. 67
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- #342
Alistair_Heaton
Mechanical
NOne Destructive Testing
Ultrasound, XRay, die pen are all forms of it.
They used some fancy new way of doing ultrasound to find and 3D map the cracks with those reactors. Its quiet in depth and you need to chase your tail in circles if you want to find out the big picture which is why I am not even going to attempt it.
Ultrasound, XRay, die pen are all forms of it.
They used some fancy new way of doing ultrasound to find and 3D map the cracks with those reactors. Its quiet in depth and you need to chase your tail in circles if you want to find out the big picture which is why I am not even going to attempt it.
We do a lot of ultrasound and X-Raying at the factory, It's for kvalité checks of welding's and Heat Area Zons.
Not shore we do it in 3D though, but is wouldn't surprise me.
We do almost everything els in 3D nowadays.
Hade my office behind theirs earlier, so have a fair picture of how it works, could not easily explain it though.
BR A
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
Not shore we do it in 3D though, but is wouldn't surprise me.
We do almost everything els in 3D nowadays.
Hade my office behind theirs earlier, so have a fair picture of how it works, could not easily explain it though.
BR A
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
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- #344
Alistair_Heaton
Mechanical
You might be interested in it as well then.
It was developed in 2010 I think. Ultra sonics is an easy concept to grasp I found but to actually know what's going on and the art of interpreting the pictures never mind setting up the test takes years to master.
It was developed in 2010 I think. Ultra sonics is an easy concept to grasp I found but to actually know what's going on and the art of interpreting the pictures never mind setting up the test takes years to master.
- Thread starter
- #345
Alistair_Heaton
Mechanical
Another article about Belgium nukes
Yes I always found it fascinating how they knew what they saw when doing ultra sound on mothers and the fetuses,
even though they at least knew what they are looking for..
When I was working in the summers when I was young I was at the archive of the X-ray department in the hospital.
An ordinarie X-ray is at least something you can se and understand at least if it's on a human.
But not exactly knowing what you are looking for or how it looks, yes I can imagine it is a skill, he who is doing it at work, has done it for at least 25 years.
Best Regards A
PS. That is partly why the elevator horn on the SE-MES annoys me. :-(
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
even though they at least knew what they are looking for..
When I was working in the summers when I was young I was at the archive of the X-ray department in the hospital.
An ordinarie X-ray is at least something you can se and understand at least if it's on a human.
But not exactly knowing what you are looking for or how it looks, yes I can imagine it is a skill, he who is doing it at work, has done it for at least 25 years.
Best Regards A
PS. That is partly why the elevator horn on the SE-MES annoys me. :-(
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
I was given the task of implementing personal safety preventive maintenance on the presses.
One thing that must be ensured is that the ram does not fall down, which can happen if the pipe on the minus side of the cylinder cracks or comes off.
Not all presses have safety valves directly on the cylinder minus side connection.
I suggested they check the tubes with ultrasound once a year, never know how it went.
i know we have a portable unit.
One problem was that it is not possible to access whole pipe.
But the for the most part the fatigue and cracking is in HAZ around the welding.
BR A
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
One thing that must be ensured is that the ram does not fall down, which can happen if the pipe on the minus side of the cylinder cracks or comes off.
Not all presses have safety valves directly on the cylinder minus side connection.
I suggested they check the tubes with ultrasound once a year, never know how it went.
i know we have a portable unit.
One problem was that it is not possible to access whole pipe.
But the for the most part the fatigue and cracking is in HAZ around the welding.
BR A
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
As I recall , the recent french and belgium nuclear reactor materials issues were related to the "anomalous" head forgings for the top and bottom pressure vessel heads forged at the le Creusot foundry. The technology used at that old foundry was unable to ensure equal carbon distribution throughout the forging , leading to sections of the heads that exceed the max allowable carbon content. This implies its fatigue life and ductility do not meet the code requirements, and the problem goes back to all forgings made at Creusot over the last 30 yrs. A review of the NDT records demonstrated fraudulent changes to the documents was needed to qualify these large pieces, and many EU nuclear plants had to be re-inspected a few years ago as a result. It has to be mentioned that today's UT equipment is far more accurate than that of 30 yrs ago , so cracks and "anomalies" that could not be detected before are now discoverable. Future nuclear plants will use forgings from japanese or russian foundries, which are more modern and can meet the required specification. The new reactor at flammanville 3 will continue to used the out of spec heads for a few years, but then replace them after a few years of operation, while hoping that severe thermal transients do not occur until then. This implies there will be another shortage of power during the outage needed to replace those heads. I am willing to bet they will rationalize more years of operation before replacement. The process used to rationalize the initial use of out of spec heads is a remarkable example of how politics overrules science , hands down.
The need for reserve capacity increases as more intermittent renewable capacity is added. In particular, a large wind storm will cause all turbines in that wind farm to shut down at the same time , to avoid overspeed of the turbines. This implies reserve capacity must quickly startup typically with no more than a 30 minute lead warning. This can be addressed by simple cycle gas turbines, and combined cycle plants that are maintained in a hot spinning reserve mode, which can be accomplished by adding a small "pony" gas turbine with small hrsg to hold the steam turbine at minimum load needed to prevent last blade recirculation issues. To avoid the need for large natural gas pipelines, it may be feasible to fuel these reserve units with either oil storage or other liquid hydrocarbon storage tanks sufficient for a few days of operation.The method of paying for that reserve capacity is another matter for the policy makers that want green energy, and it represents another cost penalty that needs to be added to the cost estimate of wind farms.
As I mentioned in earlier posts, the energiwiende that shocked the EU 12 yrs ago led to the premature retirement of over 20 GWe of brand new 50 Hz combined cycle plants in germany , so there may be available a lot of "grey market" slightly used combined cycle plants availalbe at 10% of their intial cost.
"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick
The need for reserve capacity increases as more intermittent renewable capacity is added. In particular, a large wind storm will cause all turbines in that wind farm to shut down at the same time , to avoid overspeed of the turbines. This implies reserve capacity must quickly startup typically with no more than a 30 minute lead warning. This can be addressed by simple cycle gas turbines, and combined cycle plants that are maintained in a hot spinning reserve mode, which can be accomplished by adding a small "pony" gas turbine with small hrsg to hold the steam turbine at minimum load needed to prevent last blade recirculation issues. To avoid the need for large natural gas pipelines, it may be feasible to fuel these reserve units with either oil storage or other liquid hydrocarbon storage tanks sufficient for a few days of operation.The method of paying for that reserve capacity is another matter for the policy makers that want green energy, and it represents another cost penalty that needs to be added to the cost estimate of wind farms.
As I mentioned in earlier posts, the energiwiende that shocked the EU 12 yrs ago led to the premature retirement of over 20 GWe of brand new 50 Hz combined cycle plants in germany , so there may be available a lot of "grey market" slightly used combined cycle plants availalbe at 10% of their intial cost.
"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick
Either generators, OR suitable storage. El Hierro is 100% renewable powered using pumped storage.
davefitz said:
Do wind turbines have fixed blades or are the blades angle adjustable as on a helicopter or constant speed propeller with a governor?
Yes they have the possibility for pumped storage against the border to Luxemburg, I have been on a car trip there it's quit hilly terrain.
Or they can buy pump storage capacity from Norway as Holland do.
Best Regards A
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
- Thread starter
- #352
Alistair_Heaton
Mechanical
they are adjustable pitch the same as aircraft. When the wind gets to high they feather them so they don't turn.
Okay thanks.
to avoid overspeed of the turbines.
I am not shore what is deemed as over speed?
Looking at the tests of the turbin engines from the "Flight from Denver blows engine on takeoff" thread.
It seems a turbin motor like that can generate a lot of "speed" rpms without braking.
So why cant a wind turbin handle the same?
Is it just bad construction?
Or a standard that have not been questioned?
Best Regards A
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
to avoid overspeed of the turbines.
I am not shore what is deemed as over speed?
Looking at the tests of the turbin engines from the "Flight from Denver blows engine on takeoff" thread.
It seems a turbin motor like that can generate a lot of "speed" rpms without braking.
So why cant a wind turbin handle the same?
Is it just bad construction?
Or a standard that have not been questioned?
Best Regards A
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
LittleInch
Petroleum
Tip speed is one - The wind farm turbines are enormous so tip speed can get very big for what seem like relatively low RPM, and forces on the blade, hub and tower increase.
At 60 rpm ( one rev per second), tip speed is already ~250m/sec.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
At 60 rpm ( one rev per second), tip speed is already ~250m/sec.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Okey, so if you want to have a wind turbine in stormy wheatear you make the blades shorter ?
Which makes them less effective at low windspeeds if you do not put in more blades ?
BR A
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
Which makes them less effective at low windspeeds if you do not put in more blades ?
BR A
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
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2
- #356
Yes it is common that wind machines will shut off at high wind, so it is possible to lose over 100 MW of energy in a very short time. That short time loss is hard to follow with a gas turbine, or diesel engines, that currently have very fastest ramp rates.
The best way to follow is to have several larger machines (including steam units) at less than full capacity, and ready to ramp as soon as the wind becomes unavailable.
This is part of the problem is that now a utility can't fully load the bigger machines, because they need them available for a loss of the renewables.
Not just reserve, but fast reserves. This fast ramp is hard on some of the machines, but that cost is not factored into the cost of power for the renewables.
Good news is battery storage can match the ramp rates needed for renewables, but then it is no longer available for peaking service. And the battery technology itself can have a high disposal cost.
Most peaking plants that also provide reserve power, are about 15 minute start up.
The best way to follow is to have several larger machines (including steam units) at less than full capacity, and ready to ramp as soon as the wind becomes unavailable.
This is part of the problem is that now a utility can't fully load the bigger machines, because they need them available for a loss of the renewables.
Not just reserve, but fast reserves. This fast ramp is hard on some of the machines, but that cost is not factored into the cost of power for the renewables.
Good news is battery storage can match the ramp rates needed for renewables, but then it is no longer available for peaking service. And the battery technology itself can have a high disposal cost.
Most peaking plants that also provide reserve power, are about 15 minute start up.
electricpete
Electrical
There is some debate about relative merits of the power sources. I do think there may be an attempt to put spin on the conclusion from various sides. I'm not convinced I know the full story. But I did try to think through it from some publicly available information. Take it fwiw, I'm not trying to convince anyone of anything (even though I do have an occupational stake in one of these power sources, so I have a reason to be biased if you want to view it that way).
We hear wind lost as a fraction of total lost is small. To my thinking, that shouldn't matter when comparing power sources, what should be relevant is (wind lost as a fraction of total wind) vs (nuclear lost as a fraction of total nuclear) vs (gas lost as a fraction of total gas), vs (coal lost as a fraction of total coal). Also there is some question about the denominator total... should it be total in service at the time or total forecast and more importantly what is the timeframe of that forecast. I've heard some people say wind was high in comparison to forecast, I don't know details of the forcast timeframes they're looking at and how it would compare to the others.
At any rate below I inserted an interesting graph of power vs time during the event from EIA. You ca look at the power over different timeframes, it's not necessarily straightforward. I'll put some numbers in but there is some subjectivity in that process.
The power sources in the graph are wind, nuclear, gas, coal. It appears coal and nuclear are baseload - they operate at constant load. It appears the wind and solar follow their own daily cycle (not following demand, just putting out everything they can which varies on a daily cycle) and the gas is dispatched in a time-variable fashion to match demand (we have to give gas credit for apparently being the most flexible among these sources).
The fraction of gas lost is (44-33)/44= 25% instantly ~4AM Moonday and (44-26)/44= 38% for the 3-day period M/T/W. Maybe I penalized them too much for starting at 44 which was probably a daily peak but oh well.
The fraction of coal lost looks to be 10% instantly and 30% for the M/T/W period.
The fraction lost of nuclear is exactly 25% instantly and 25% for the M/T/W period (1 out of 4 almost-identical plants tripped early Monday and came back Thursday).
The fraction of wind lost is 0 instantly maybe 40-50% for the three day period from the prior few days average. More importantly it decreased to 0 Monday night which is exactly when it was needed most to my thinking (that was the coldest time in my area of the state).
The fraction of Solar lost is not much but it goes to 0 at night when winter heat demand is highest so it is not helping much in this scenario.
Wind didn't have the rapid change of the others, but it was not particularly the rapid change that caused the problem in this particular event (it could in others), in this event there was sustained deficit of power generation and wind decreased as much or more than any of the other sources during the 3 day period. Abbot's comments were controversial and mostly rejected by the press. I didn't agree with everything he said but i think there's a kernel of truth in there depending on how you slice it. Certainly we know wind and solar are susceptible to weather even outside of extreme events, so it seems obvious the system should not be relying heavily on them. But then in a sense if ERCOT can't depend on their capacity when needed most then they are getting a free ride. In an unregulated environment where wind is already getting huge subsidies, it's part of the landscape to consider when comparing power sources.
I do realize there's a lot of other lessons to be learned and a lot of different ways to compare power sources. Winterization can probably be enhanced for any/all of these types of sources... they operate reliably up north, so they certainly should be able to do the same down south.
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(2B)+(2B)' ?
We hear wind lost as a fraction of total lost is small. To my thinking, that shouldn't matter when comparing power sources, what should be relevant is (wind lost as a fraction of total wind) vs (nuclear lost as a fraction of total nuclear) vs (gas lost as a fraction of total gas), vs (coal lost as a fraction of total coal). Also there is some question about the denominator total... should it be total in service at the time or total forecast and more importantly what is the timeframe of that forecast. I've heard some people say wind was high in comparison to forecast, I don't know details of the forcast timeframes they're looking at and how it would compare to the others.
At any rate below I inserted an interesting graph of power vs time during the event from EIA. You ca look at the power over different timeframes, it's not necessarily straightforward. I'll put some numbers in but there is some subjectivity in that process.
The power sources in the graph are wind, nuclear, gas, coal. It appears coal and nuclear are baseload - they operate at constant load. It appears the wind and solar follow their own daily cycle (not following demand, just putting out everything they can which varies on a daily cycle) and the gas is dispatched in a time-variable fashion to match demand (we have to give gas credit for apparently being the most flexible among these sources).
The fraction of gas lost is (44-33)/44= 25% instantly ~4AM Moonday and (44-26)/44= 38% for the 3-day period M/T/W. Maybe I penalized them too much for starting at 44 which was probably a daily peak but oh well.
The fraction of coal lost looks to be 10% instantly and 30% for the M/T/W period.
The fraction lost of nuclear is exactly 25% instantly and 25% for the M/T/W period (1 out of 4 almost-identical plants tripped early Monday and came back Thursday).
The fraction of wind lost is 0 instantly maybe 40-50% for the three day period from the prior few days average. More importantly it decreased to 0 Monday night which is exactly when it was needed most to my thinking (that was the coldest time in my area of the state).
The fraction of Solar lost is not much but it goes to 0 at night when winter heat demand is highest so it is not helping much in this scenario.
Wind didn't have the rapid change of the others, but it was not particularly the rapid change that caused the problem in this particular event (it could in others), in this event there was sustained deficit of power generation and wind decreased as much or more than any of the other sources during the 3 day period. Abbot's comments were controversial and mostly rejected by the press. I didn't agree with everything he said but i think there's a kernel of truth in there depending on how you slice it. Certainly we know wind and solar are susceptible to weather even outside of extreme events, so it seems obvious the system should not be relying heavily on them. But then in a sense if ERCOT can't depend on their capacity when needed most then they are getting a free ride. In an unregulated environment where wind is already getting huge subsidies, it's part of the landscape to consider when comparing power sources.
I do realize there's a lot of other lessons to be learned and a lot of different ways to compare power sources. Winterization can probably be enhanced for any/all of these types of sources... they operate reliably up north, so they certainly should be able to do the same down south.
=====================================
(2B)+(2B)' ?
If the blades on a windmill are variable why would you ever feather them? Wouldn't you just reduce pitch so they extract less power from the air allowing the load to keep the speed constant?
Keith Cress
kcress -
Keith Cress
kcress -
I see that there is blue for hydro in the above chart but there is no line?
Then it hard to get a proper picture when the lines are not on top of each other.
This is the chart for Sweden to day.
We use hydro to even out the wind power, I have no data on how fast ju can ramp up, but I would say you just need to pull the plug.
If there would be any possibility the create a hydro storage for balancing the wind power, for Texas and for Belgium why choose something els?
And for a small country as Belgium it will not work to be alone and not exchange power with others when needed.
And if the loss from wind farms get so great when storming it would be advisable not to put all the eggs in ones basket, rather try to have them in smaller groups in different places.
And I know it is easier in all ways to have them all in one place, and you choose location from the best wind possibility's.
But sometimes you maybe have to make other priorities to be safe, maybe not something for Texas though ;-)
Or maybe you need to have 2/3 wind generators for normal conditions an 1/3 that really can utilize the stormy winds when the others stops working?
Best Regards A
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
Then it hard to get a proper picture when the lines are not on top of each other.
This is the chart for Sweden to day.
We use hydro to even out the wind power, I have no data on how fast ju can ramp up, but I would say you just need to pull the plug.
If there would be any possibility the create a hydro storage for balancing the wind power, for Texas and for Belgium why choose something els?
And for a small country as Belgium it will not work to be alone and not exchange power with others when needed.
And if the loss from wind farms get so great when storming it would be advisable not to put all the eggs in ones basket, rather try to have them in smaller groups in different places.
And I know it is easier in all ways to have them all in one place, and you choose location from the best wind possibility's.
But sometimes you maybe have to make other priorities to be safe, maybe not something for Texas though ;-)
Or maybe you need to have 2/3 wind generators for normal conditions an 1/3 that really can utilize the stormy winds when the others stops working?
Best Regards A
“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein
electricpete
Electrical
High Anna.
We have no hydro in our state. Certainly in my part of the state, it's very flat and the rivers are slow.
I haven't heard much discussion of storage as an option. I think a more typical use is to help accommodate variably daily supply (wind, solar) and variable daily demand rather than to accommodate sustained loss of generation sources. I'm not sure. Maybe there is something we're missing.
The windfarms are installed by individual investors whereever they want. As far as I know there is no guidance from the state on where that has to be, so no central coordination over where they end up installed (other than they have to build up the transmission system to install them in some locations).
> then it hard to get a proper picture when the lines are not on top of each other.
I like it in the format I had before for the purposes of judging how each type of power varied over time and what fraction of each is lost. But here is similar format to what you described for the recent Texas event. I guess it does do a better job at showing the steady increase in total demand up to that winter peak record 67GW and the sharp decrease where multiple sources tripped and then continued decrease even as demand should have been going up as it continued to get colder throughout the day on the 15th (our coldest night was the night of the 15th / morning of the 16th... where the graph stops at 00:00 on the 16th would have been near coldest albeit not a normal power peak time).
=====================================
(2B)+(2B)' ?
We have no hydro in our state. Certainly in my part of the state, it's very flat and the rivers are slow.
I haven't heard much discussion of storage as an option. I think a more typical use is to help accommodate variably daily supply (wind, solar) and variable daily demand rather than to accommodate sustained loss of generation sources. I'm not sure. Maybe there is something we're missing.
The windfarms are installed by individual investors whereever they want. As far as I know there is no guidance from the state on where that has to be, so no central coordination over where they end up installed (other than they have to build up the transmission system to install them in some locations).
> then it hard to get a proper picture when the lines are not on top of each other.
I like it in the format I had before for the purposes of judging how each type of power varied over time and what fraction of each is lost. But here is similar format to what you described for the recent Texas event. I guess it does do a better job at showing the steady increase in total demand up to that winter peak record 67GW and the sharp decrease where multiple sources tripped and then continued decrease even as demand should have been going up as it continued to get colder throughout the day on the 15th (our coldest night was the night of the 15th / morning of the 16th... where the graph stops at 00:00 on the 16th would have been near coldest albeit not a normal power peak time).
=====================================
(2B)+(2B)' ?
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