Bishop Hill German industry counts cost of renewables
Aug 18, 2012 Energy: grid Der Spiegel is reporting that all those wind farms in Germany are having an unfortunate effect on the stability of the electricity grid and that manufacturing industry is counting the cost.
It was 3 a.m. on a Wednesday when the machines suddenly ground to a halt at Hydro Aluminium in Hamburg. The rolling mill's highly sensitive monitor stopped production so abruptly that the aluminum belts snagged. They hit the machines and destroyed a piece of the mill. The reason: The voltage off the electricity grid weakened for just a millisecond.
Workers had to free half-finished aluminum rolls from the machines, and several hours passed before they could be restarted. The damage to the machines cost some €10,000 ($12,300).
A problem that is no doubt coming to an employer near you soon.
Reader Comments (37)
Not here bish, that was avoided by the Alcan Plant closing its doors altogther and high energy costs were a factor. The government have forseen claims for damages and are avoiding it by creating conditions that make sure heavy industry moves abroad. (sarc!)
This sounds a bit unlikely: the supply dipped for a millisecond (1/20th of a 50Hz mains cycle) and the whole line crashed? There are specs for mains supply drop-outs etc and I'm pretty sure that a 1ms drop out is well within spec.
"The rolling mill's highly sensitive monitor stopped production so abruptly that the aluminum belts snagged" - Sounds like someone didn't design the mill system to tolerate normal mains glitches - or maybe just some other fault.
I don't think it's likely that this one can be blamed on Global Warming (tm).
http://www.energy.siemens.com/hq/en/power-generation/gas-turbines/
Guess which country makes the best Gas Turbine Generators
It was also discussed at http://junkscience.com/2012/08/17/energy-revolution-hiccups-grid-instability-has-industry-scrambling-for-solutions/
The use of the term a "millisecond" was ascribed to a non-technical journalist by some commentators.
Expert advice, which (I'm happy to say . . .) concurs with my own experience in industry, is that the article is, at best, over-egging the pudding.
Short interruptions, spikes and the like in the mains supply are commonplace and always have been the world over. Any piece of kit in any way sensitive to them that does not have suitable filtering and/or so-called Uninterruptable Power Supplies is thoroughly incompetently designed. I do not for a moment believe that the controls of e.g. a German aluminium smelter are incompetently designed. A more-or-less lengthy power cut is a different matter, of course.
As I see it, the issue is not whether the journalists understand the real problem (they never do) but why it is surfacing so regularly now.
As others have said, there's lots of stuff that you can blame on wind, but this doesn't sound like one of them. It seems more likely that there was a network fault in the distribution system near the plant that led to a voltage dip. Depending on the severity of this, and how quickly the fault was cleared, some machines can stall. Usually, faults are cleared in about 100ms, but on a distribution system (say 38kV and lower), the fault clearance can be quite a bit longer. Germany forms part of a massive interconnected power system all across central europe. There are all sorts of reasons why the local network could have been weakened - line outages / maintenance etc, which could make voltage dips worse.
With DaveB on this one.
DaveB has it right -- if one has an expensive piece of equipment which is sensitive to voltage changes, one would install a power filter, as the mains have all sorts of minor irregularities. I suspect the answer is that the mill has such a filter, and the "highly sensitive monitor" measures the output of the filter. When the filter can no longer maintain its output voltage within tolerance, the machine will be shut down to prevent worse damage. Perhaps the millisecond referred to, is how quickly the shutdown is initiated when tolerance is exceeded. Likely the mains disruption was considerably longer in duration.
@ Gareth, DaveB and Alan
It is much too quick to say that the voltage dip cannot be attributed to the variability of the German renewable energy. Obviously, the usual spikes that have been with us for as long as electricity grids have been in operation can be managed by any industry. The wind- and solar farms however create problems that have not been with us before, especially now that they start to have more than 5% of energy contribution to the grid.
When a windfarm suddenly starts to provide a lot more ore less energy this has to be compensated by the other generators,mostly by gas (OCGT or CCGT) because coal and nuclear cannot change ouptput quickly enough. When the OCGT/CCGT plant(s) providing compensation is (are) not local to the windfarm showing a lot of variation, the time constant in the feedback loop may become too large to keep the control system stable. This may result in oscillations, which have NEVER been with us before. To think that the power grid can be safely controlled by prediction is quite dangerous, when sudden changes occur at uncertain times as with wind and solar. The usual prediction of power demand over the day has a much larger time constant and is much easier to deal with. Generator control has to be automatic and prediction of unreliable sources like wind and solar is analogous to manual control, leading to system faults.
How the grid reacts to these problems is uncertain. Parts of it may switch off for shorter or longer times. On certain lines in the grid out-of-spec frequencies or voltages may occur. Currently I see a lot more reports of power outage than we used to have and I think it is fairly safe to attribute these instabilities to the continuously increasing contribution from solar and wind energy farms.
The article in the Spiegel appears to be about just one instance, but if you read between the lines you can see that many more such instabilities have occurred and that companies who used to depend on the power grid are starting to provide safeguards for themselves.
Unfortunately, even a power grid with its many switches, generating plants and user loads is so complex that computer modelling of it is difficult, especially when new situations are starting to occur. It is only recently that the characteristics of windfarms are becoming known. Luckily Germany has to deal with this first, because of their stupid decision to close down nuclear generating plants and trying to exchange these with offshore windfarms, far away from the majority of power users. A Chinese would probably say that Germany's energy future is "interesting". In any case, other countries had better look closely before they follow suit.
Sounds like Der Spiegel, even though the reason given for the outage could be inaccurate, is simply reflecting a changing mood in Germany towards renewables; too expensive, too many problems. It may be that Germany's hitherto rigid ideological stance on CAGW is about to give way to pragmatism. No sane nation will deliberately weaken itself for he sake of ideological purity. Perhaps 'September 11' would care to comment; I believe he is German.
How the heck can Germany manage toproduce aluminium competitvely with the price of electricity in Germany being what it is? It cannot compete for sure, unless the industry is subsidised. But then the EU laws do not allow for subsidies to industries. Is Germany breaking EU rules?
I happen to have worked in that aluminium rolling mill, also lots of steel mills. The safety override is to save the lives of the operators. It's because the rolling speeds can be such that if the strip misses the next stand it can slice people in two.
You don't muck about with such powerful equipment. The Germans and we have to decide whether we pander to the greens with no CO2 savings or keep unemployment low and employment skilled.
From http://www.aluminiumleader.com/en/serious/industry/
Wikipedia claims that it takes 15kwh to produce 1kg of aluminium so using those figures I calculate that Europe's relatively clean electricity generation should decrease by 8.7GWh and move to countries with relatively dirty electricity generation.
**NOTE: I think they have the production figures wrong. It should be t.p.a. (tonnes per annum) rather than m.t.p.a. (mega tonnes per annum).
Re: Albert Stienstra
There are additional problems caused by power fluctuations.
In the UK the grid frequency is maintained at 50Hz. If demand is greater than supply then the frequency drops, if demand is less than supply then frequency increases. The national grid has to maintain the frequency to within 1% (see http://www.nationalgrid.com/uk/Electricity/Balancing/services/frequencyresponse/).
Anybody that has emergency power generation (hospitals, data centres, telecomms etc) will have the backup generators kick in when the frequency drops below a certain level for a period of time and disconnect themselves from the grid. They see the drop in frequency as an indication of imminent power failure.
This actually happened at a company I was with a few of years ago when 2 of the UK's power stations suddenly went offline. There was no power cut in the area but the data centres kicked in the diesel generators and disconnected themselves from the grid.
TerryS
It's possible that "m.t.p.a" is intended to mean metric tons per annum = your tonnes per annum.
This was a rolling mill operation, the feedstock is slabs of aluminium that has already undertaken electolysis elsewhere, there is a 6% import duty on raw aluminium ingot and slab which partly protects the EU Aluminium electolysis industry, there are further import duties (punative anti dumping in the case of China) on finished aluminium foil which this rolling mill would have been producing.
So you put import duties in place to protect an industry which you then penalise by increasing their energy costs.
Mad but that's the EU.
I think that the problem was with equipment rolling, not smelting, the aluminium. The rolling mills involve large rollers with metal essentially flowing down the line being shaped. A change in the voltage or frequency outside of design parameters causes the motors to slow or speed up, which is quite bad given the momentum involved. Conversely smelters can be turned off with little problem as long as the electricity is restored before the alumina solidifies.
Also, there is a huge difference (something like 90%) in the electricity required in the primary smelting of aluminium compared to recycling aluminium. It can be economic to recycle aluminium with high cost electricity, given so little electricity is needed.
Hi,
Back in the day, when I worked on support for DEC mini computers, we had lots of process control and monitoring kit in steel and aluminium plants.
One of the most hairy and bowel loosening places to be was a steel strip mill in S Wales. They used one of our PDP 8's to control a flying sheer, This is a moving sheer (cutter) that is accelerated down the line until synchronised with the steel strip flowing at a high rate on the way to the winders. If the PDP got it wrong ( or hiccuped), and the sheer operated out of sync, the steel strip would buckle and throw several tons of itself upwards, smashing against the roof of the strip mill, the workers would all dive for cover. The worst thing was to demonstrate that you had fixed the problem, because if you hadn't it got very expensive and noisy again!
We had another system in an aluminium smelter to monitor production, it worked for some time and then one of the washing machine sized disk drives died, The engineer who installed the replacement drive rang me up for advice, Part of the installation process was to set up the heads of the drive in the correct positions using a standard pack and an oscilloscope. The engineer complained that he was on his third scope and none of them would work, however, if he took the scopes to another part of the plant they worked fine, After initial disbelief, I found out that four feet above the system were two bus bars carrying something over 4000 amps d.c. for the smelter arcs. The electron beams in his oscilloscopes were being deflected off the screen by the magnetic filed from the bus bars, what was amazing was that the DEC PDP11 and sundry peripherals worked in that environment for years with no problems!
cheers
P
http://af.reuters.com/article/energyOilNews/idAFL5E8DP0GZ20120225
Seems Germany isnt only buying in its electricity from France
Throwing out the baby with the bathwater.
Germany slowly throwing away its lead in Engineering excellence.
So will Germany ban investment in and export of spare parts to other Nuclear Industries abroad and outside the EU.And will it stop Nuclear Fuel Reprocessing.
They said they banned Nuclear Power because of Fukeshima .The Baltic Coast is hardly likley to get hit by a Tsunami is it.
@Albert and others: The conventional generators (gas turbines and other thermal plant) perform frequency regulation and voltage regulation all the time. Their governors are constantly adjusting the mechanical power into the machines to keep the frequency at 50Hz. Wind fluctuations can and do show up as frequency jitter on power systems, but there's not nearly enough wind in Germany to make much difference. Remember that the mainland europe electrical system is massive - its about 500,000MW, and has a huge amount of electrical inertia due to the stored rotational energy in the conventional machines. The issue with wind turbines is that they have no inertia - they feed their power in through power electronic converters that turn the variable frequency coming from the wtg generator into 50Hz electricity. Solar is a different matter and is not nearly as predictable as wind. On wind fluctuations, there is a simple solution to these - you curtail the wind farm so that it produces less than its maximum - this effectively takes wind gusts etc out of the equation. Obviously this has a big impact on the economics of wind, which many of the reports have not addressed.
The frequency is the same everywhere in a synchronous system - the frequency in edinburgh is the same as the frequency in london. Voltages however do change from place to place. These are adjusted by changing the field current on the generators and adjusting the tap ratio of the various transformers in the system, as well as switching in and out capacitors and inductors (that make the voltage higher or lower). Thus as long as there is a reasonable geographical spread of generation, it makes no difference to the overall energy balance where that power feeds in. Obviously you could not have all your generation in Scotland and all your load in the south of England - that would not work. You also cannot much too much generation into distribution systems.
On frequency, all system operators cover for the loss of the largest generator by keeping enough spinning reserve that can pick up the difference within a few seconds. Generally speaking frequency can drop down to 49Hz or up to 51Hz before bad things start happening. Below 49Hz, underfrequency load shedding relays start dropping load all over the system that will help restore the overall energy balance. You need to get down under 48Hz or over 52Hz before conventional machines start dropping off the system.
http://www.guardian.co.uk/environment/damian-carrington-blog/2012/may/23/energy-nuclear-power-germany
http://www.guardian.co.uk/environment/blog/2012/may/28/truth-germany-nuclear-phase-out
Both missed the point .Germany gets rid of its Nuclear Reactors so can Iran have theirs.
One of the big problem with windfarms, together with their lack of predictability and no inertia, is that there output is synthetic AC from frequency converters. That means they put out a waveform that is not a sinewave but a chopped up block form that has been smoothed. They might have smoothing capacitance but this impure waveform needs the rest of the grid to filter.
If a fault happens in a grid line or switchyard near the windfarm, they lose the trigger signal that the windfarm's converters are trying to match. The farm can then put voltage spikes into the grid trying to match the fault. They often have protection that if set correctly, will take the farm off line. This lack of low voltage ridethrough is a known fault.
http://en.wikipedia.org/wiki/Low_voltage_ride_through
They also cannot provide much short circuit current either which is a related fault.
Rolling mills invariably have variable speed drives for their motors. These are also frequency converters. However, they also backfeed spiky signals into the grid, especially if the motors are big. Everyone is supposed to have filters on their kit to try and get rid of the spikes, but these are generally only designed for optimised conditions. When things start going wrong and faults occur, the filtering is no longer effective so plant goes outside its operating parameters so the protection takes it offline.
Easy to predict, very hard to protect from - and it is going to get worse as the grid inertia drops. If you have a big strong interconnected grid with lots of thermal or hydro generators all over the grid, no problems. Move the grid to being long and stringy, with wind generators a long way from load and all hell will break loose. That is what is starting to happen now in smaller grids like NZ.
I doubt Germany will jeopardise Das Autos.
They will secure a reliable and cost effective effective energy supply.
Can't run production lines on intermittent power. Once the political dancing is over they will revert to having a reliable source of energy within their control. If not fissile then it will be fossil.
I used to work for a manufacturing company. When there was a power dip (usually a crispy critter taking out a transformer) a production run was ruined. One of my jobs was to download the event from a data logger so that the company could claim compensation from the elctricity supplier. I can't remember the exact timeframe but if the lights flickered it usually meant I had to drop what I was doing and start downloading.
Greensand said:
"I doubt Germany will jeopardise Das Autos........ Once the political dancing is over they will revert to having a reliable source of energy within their control. If not fissile then it will be fossil."
They have already started. I can't remember precisely how many but they are building several more Lignite and coal
plants.
Lignite by the way makes coal look greener than a green thing.
And we all thought the Germans were obsessed with the environment and nature and stuff. Bless!
Hi Andy: latest figure is 23 supercritical power plants.
At last, the normally reticent, self-deprecating engineers who are the antithesis to the climate science poseurs are at last stirring themselves.
It's a bit like the Ents in the Lord of The Rings, slow to get riled but a deadly force when they take on the equivalent of the Orcs who have almost taken over Science.
"At last, the normally reticent, self-deprecating engineers who are the antithesis to the climate science poseurs are at last stirring themselves."
And once stirred they are very seldom shaken; and never, never, ever removed from the data.
I'll spare you the new book that it would take to support this hypothesis - so just the hypothesis.
The desire by Dr Strangelove types around Germany to move to a green economy set in train the global financial crisis. You can't fool around with global finacial balances and expect all of your models and ideals to turn out 100% correct. Germany started a nosedive that still sees the ground getting closer to its propellor. The zealotry displayed by Merkel in wanting to close down German nuclear is underscored by this aluminium smelter example. Simply, you can't smelt aluminium economically using windmills or solar power. The world's alumina and aluminium industries have been like nomads wandering the world in search of long term, reliable, cheap electricity. There is a huge cost associated with a freeze of a pot line. Windmills on a large grid place demands on more than frequency and load. They add spike noise and play with quadrature.
The financial distortions that allow Germany to muck around with primary aluminium, driven partly by auto making, are severe enough to disrupt other Euepoean economies. If germany cops a huge loss on windmill aluminium, it tries to make it up by taking funds from other EU countries. Those like Spain that also had the solar/windmill dream can least afford the extra imposts. That's a small part of the negative side of the story.
The positive side of the story of German green incompetence is much easier to tell. There is none.
Howerver, Germany might in time learn a little humility and stop hitting beautiful horses with whips to make them do acts never intended for a horse body. Like it was never possible to make a green bodied economy perform without whipping.
If this theme interests you, Google Hans-Joachim Schellnhuber and read some of his outlandish statements. I've never met him, so I can't judge face-to-face, but his writings and videos contain a touch of the manic. He advised Duetsche Bank and was with the Tyndall centre in England, setting policy on global warming and is still doing related harm elsewhere. Please keep him away from the red buttons that fire ICBMs.
On the other hand we could all write to the Energy Select Committee, but with it populated by the likes of Yeo and Gummer , we might be wasting our breath.
This was foretold in the 2005 Eon-Netz Wind Report, http://www.nerc.com/docs/pc/ivgtf/EON_Netz_Windreport2005_eng.pdf
Guaranteed wind power capacity below ten percent – traditional power stations essential
In 2004 two major German studies investigated the size of contribution that wind farms maketowards guaranteed capacity. Both studies separately came to virtually identical conclusions, that wind energy currently contributes to the secure production capacity of the system, by providing 8% of its installed capacity. As wind power capacity rises, the lower availability of the wind farms determines the reliability of the system as a whole to an ever increasing extent.
Consequently the greater reliability of traditional power stations becomes increasingly eclipsed. As a result, the relative contribution of wind power to the guaranteed capacity of our supply system up to the year 2020 will fall continuously to around 4%.
In concrete terms, this means that in 2020, with a forecast wind power capacity of over 48,000MW (Source: dena grid study), 2,000MW of traditional power production can be replaced by these wind farms.
Impact on neighbouring grid operators
Neighbouring European transmission system operators are also increasingly affected by the high wind power feed-in in Germany. The reason for this is that power always flows within the grid according to the laws of physics and seeks out the route of lowest electrical resistance. As a result, sometimes a significant proportion of the wind power infed in Northern and Eastern Germany flows in a loop through the grids of the neighbouring countries of the Netherlands, Poland and the Czech Republic, where it leads to significant loads on the operating resources.
Large thermal power stations do not disconnect from the grid even following serious grid failures, instead they generally trip into auxilliary services supply and until then, "support" the grid. Wind farms, however, have so far disconnected themselves from the grid even in the event of minor, brief voltage dips. Experience shows that this can lead to serious power failures.
Geoff Sherrington:
Re Schellnhuber, he still advises Deutsche Bank, as did Pachauri until recently and as do Lord John Browne, Lord Oxburgh, former UNEP Exec Sec Klaus Topfer and a few more on the AGW gravy train:
https://annualreport.deutsche-bank.com/2011/ar/supplementaryinformation/advisoryboards.html
Lord Stern is on Schellnhuber's Potsdam "Scientific Advisory Board", with Brian Hoskins of Imperial Grantham, Carol Turley, Tyndall Plymouth, Jennifer Morgan, ex WWF, now World Resources Institute, (Al Gore is a board member). Schellnhuber in return is a member of the Grantham Institute Advisory Board, which covers both Stern's LSE and Hoskin's Imperial versions. In 2009, Stern and Potsdam Deputy Director Edenhofer wrote a pamphlet for the G20, "Towards a Global Green Recovery" http://www.pik-potsdam.de/members/edenh/publications-1/global-green-recovery_pik_lse
Edenhofer is the who admitted IPCC was about wealth re-distribution,
http://wattsupwiththat.com/2010/11/18/ipcc-official-“climate-policy-is-redistributing-the-worlds-wealth”/
The Bishop had a post last year about Schellnhuber and the start of the Tyndall Centre, (Mike Hulme)
http://www.bishop-hill.net/blog/2011/11/29/schellnhuber-and-the-tyndall-centre.html. He is still described as a Distinguished Science Advisor for the Tyndall Centre.
The point is, he is not a lone wolf, he is part of the mainstream.
CV here, as he was invited onto yet another academic board, more institutes with the same people, more "consensus": http://www.santafe.edu/about/people/profile/Hans%20Joachim%20(John)%20Schellnhuber
Thank you DennisA. The info on which I relied was several months old. In due course a number of prior global warming mutual admirations will reach the rats/sinking ship stage, so I tend to use 'was' rather than 'is' as a number of post-nup business/banking contracts are being dusted off by lawyers and confusion is rising in international financial circles. Re confusion and nuptials analogy -
"Instead of getting married again, I'm going to find a woman I don't like and giver her a house." Attributed to singer Rod Stewart.
I hear the German right are making accusations that it was a Greek dip. A taramasalata..../coat
Re:Albert Stienstra, "When a windfarm suddenly starts to provide a lot more ore less energy this has to be compensated by the other generators"
Not pointing at you particularly, but why are the windfarms not responsible for providing ballanced power to the grid? Why is it the other grid contributors must compensate for wind farms?
The imballance is caused by the wind farms. Surely it's the wind farms who are equaly responsible for a ballanced grid. And if they do not take responsibility for a ballanced grid, then they should be found reponsible for machinary damages caused by an unballanced grid in a court of law.
My Dear Greg, you forget that the windmills are cash cows for the elite either directly or via carbon trading. They are intended to impoverish the rest of the population in a return to Edwardian aristocratic control.
The other part of the scam was btl. The only way out is to create a new Labour Party to represent the dispossessed [the Marxists have been suborned by the elite-controlled Red-Green Alliance, a cover for the SWP].
@ Greg Cavanagh, Aug 20, 2012 at 3:51 AM \
I completely agree with you, with "other generators" I meant other than windmills. Indeed, windfarms should have local OCGT/CCGT backup, as is the case here in Flevoland, where I live. When the backup is local and the electricity provision constant, the electricity grid will not become instable. Germany currently has a big problem with their offshore and also onshore windfarms, which are mainly located in the north, while most of the industry is located in the south (Ruhrgebiet, Bayern etc.). They do not have local backup.
However, when the OCGT/CCGT gas backup is local, it quickly becomes clear that switching off the windmills and running CCGT at optimum load is more economical with regard to electricity provision as well as CO2 emission.
For more detailed information see http://www.clepair.net/CBS-aug2012nl+eng.html. Unfortunately the English version is aimed at insiders; the Dutch version is much more detailed. The reason for this is that in the Netherlands the politicians are even more backward with regard to these issues than in the UK, where a reasonably large fraction of MPs is already saying that subsidies to windfarms should be curbed. There is more work to be done here; I hope the UK will soon provide a good example.