Renewables Experiment in Oz - keep watching

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Another milestone in Australia this week with the last coal fired power station in South Australia closed down. Going to be an interesting experiment moving forward as some are claiming that it's bright light news, others looming disaster. Have been accused of bias before (Tasmania discussion), so will try to even out the spread of information from a couple of directions, however I'm leaning towards the latter outlook. First off, how that place is situated in the Australian grid. Oldish pic below, but it's not really changed that much except in capacity. For reference, Oz is about the same size as the US (excluding Alaska), so you should have a mental frame of reference. South Australia is that bit in the lower middle (capital Adelaide), and is connected to the eastern Seaboard by two interconnector paths. (the dotted line to Tasmania is THEIR interconnector, it's still broken, after nearly 6 months, and they are running diesel gen sets to keep the lights on). South Australia has been installing masses of wind turbines, more than enough nameplate capacity to keep the state running when the wind is blowing. When the wind IS blowing there's often export to the RHS of the country. Wind, being bid in at $0 as it's harvesting energy, and not able to react to the market pushes the prices down when it's blowing. Under very high wind conditions, the prices go negative, with the traditional generators having to pay money to generate (takes about $50-$100k of fuel to fire up a coaler, so brief negatives will be ridden through)...funnily, the wind has been blowing too hard lately at times and they have to get shut down. AC power is a funny thing. Voltage can be raised and lowered through transformers, or generator excitation. Different loads shift the link between voltage and current, the "power factor" is the percentage of the theoretical power that you can actually get out of the volts and amps that you have due to the "phase shift" between them...get the phase shift way out, and the volts and amps available can be completely out of phase and the available power is zero...the big generators (hydro, nuke, coal, big gas) have VAR (volts Amps Reactive) import and export capabilities to fix the power factor locally...can be done grid side with capacitor banks (Static VAR compensation), or synchronous condensers (generators run without a power source). AC does some crazy things over long distances, with things like the Ferranti effect meaning that the voltage at the far end of an energised line can be significantly higher then the voltage at the power end...system design is crucial. Every synchronised generator runs in lock step with each other. Load goes up, and frequency drops, and the generator governors initially compensate and then the controls systems load up and follow. Load drops, frequency rises, governor drops off load, and the control system follows. These wind and solar systems are "asynchronous", they aren't regidly connected to the grid like the big gens are, they are akin to electric induction motors that are driven faster than the grid frequency and thus pump POWER into the grid, but not any of the other things. They require the grid to be there in order to generate anything. Like a "reverse" load, when they power up, the generators see that like a load drop, frequency goes up, and the synchronous machines compensate. Their load drops, frequency drops and the synchronous machines bump their gen up a bit to compensate...Again, these asynchronous machines provide no grid stability features other than power. Sitting in the control room, you can see how this influx of power affects the grid...Units are being ramped up for say the evening peak, then a gust comes through the system and the governor responds down to a frequency event, only to have leave the machine short of target once the gust is gone...same with clouds over the solar farms etc. Now back to South Australia...as can be seen, it's at the end of two long transmission lines that link it to the main Eastern Seaboard of Australia. S.A. had a mix of power sources, gas thermal (I used to fish around their outfall when I was a kid), gas turbine, coal (brown, and a little black) and increasingly now wind. There's been an emergence of diesel generators as the wineries need a reliable supply for their operations, and have installed diesel gens for security, which do get called on at times. Due to the disruption of wind, and the Oz gas price hikes (we are exporting our gas to improve the greenhouse performance of other countries), the gas and coal have become non-viable, and there are mothballed plant all over the place. Northern closed last week. Torrens Island A (gas thermal) is slated for next year, leaving Torrens Island B as the only big machines, mostly on line. The wind blows, and supplies the state with power, it doesn't and they get it from the brown coalers, which include Hazelwood (google Hazelwood power station, it's another story). Go up a few paras on what grids need for stability. The state is losing that capacity at their end of the line. Late last year, the southern most of the two lines was scheduled for maintnance, leaving only a single contingency. The regulator considered the risk of separation of S.A. from the grid was a "credible" contingency, and started to make arrangements with the generators to be able to supply "FCAS" (Frequency Control Ancillary Services with the generators who were able to provide it...bidding war erupted which made those services massively expensive (it's a free market, and opportunity was there, so why not). State DID get disconnected, and frequency was berserk, as the synchronous machines were required to counter the variability in the isolated grid, while being a much smaller part of it...balancing a broom on your finger. (Funnily enough one of the Eastern seaboard generators got slammed financially for the costs of controlling that event even 'though they weren't connected to it). Here's the regulator's report on the event. and to provide balance, an alternate view of the event from a totally unbiased source. . Well last week they've lost another 500+MW of schedulable power at their end. To compensate, another 500+MW of wind is being installed, and one of the interconnectors to the eastern seaboard is getting a 190MW upgrade. Why post all this ? a) to show that it's not as easy as plugging another wind turbine into the grid in Iowa. b) it's actually an interesting experiment happening in real time as to how to decarbon the grid and keep it running. Personally, I see South Australia heading for virtually a state wide blackout at some point in the not too distant future.... Happy if they don't, happy if I'm wrong, but that state already has the highest cost, least reliable electricity in the market.
 
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They have decided to let our last 2 coal burners run until 2022 now. One of the providers is paying to keep them online. Auckland...it's where the money is. I can tell when they are on by steam vents, most days one is on, sometimes both. It's like a ghost town there now, the carpark is almost empty, and we don't do any work for them anymore.
 
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Great news because when everyone quits using coal around the planet it should be cheap for us to use, since it won't be a demanding market. Which equals cheap power.
 
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Have they been installing NGK's massive system batteries with inverters for off-wind times? Seems that is the wave of the future. Solar and wind to battery to inverter to grid. Let the batteries and inverters isolate the grid from direct effects of "green energy" spikes and lulls ...
 

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Originally Posted By: BrocLuno
Have they been installing NGK's massive system batteries with inverters for off-wind times? Seems that is the wave of the future. Solar and wind to battery to inverter to grid. Let the batteries and inverters isolate the grid from direct effects of "green energy" spikes and lulls ...
There is talk that they will have to. One of the main problem with these things is "capacity factor". We can run a 500MW power station at 90-95% nameplate rating for months on end, generating an average of 450MW, with 90%+ reliability. To supply a grid reliably with the big machines needs about 20-30% more machines to cover breakdowns, trips and shutdowns. Wind has a capacity factor of about 20%, solar (obviously) much less than 50%. Here's S.A. for May. That big peak to the left of the chart is nearly enough to run the state...the greens make much publicity on those couple of days when the state was "fully supplied by wind"...in spite of the grid stability control provided by the coal/gas at the remote end. Problem is look at the large periods of time that the 1,600(ish) Mw isn't being met. So in a carbon free (and nuke and hydro free, as the Greens accept neither of them either) you need to install 4 times as many panels/wind turbines as the load that you need, and Gigawatt Days worth of storage to suck up the peaks and spread it out. I've got no problem with a healthy mix of traditional/new tech, but the debate is overly simplistic, and one sided in the media.
 
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Originally Posted By: Shannow
These wind and solar systems are "asynchronous", they aren't regidly connected to the grid like the big gens are, they are akin to electric induction motors that are driven faster than the grid frequency and thus pump POWER into the grid, but not any of the other things. They require the grid to be there in order to generate anything. Like a "reverse" load, when they power up, the generators see that like a load drop, frequency goes up, and the synchronous machines compensate. Their load drops, frequency drops and the synchronous machines bump their gen up a bit to compensate...Again, these asynchronous machines provide no grid stability features other than power.
Shannow, can you explain the purpose of synchronous condensers being installed at the wind farms? Is it to alleviate this problem or is it unrelated? I'm just an accountant in the power generation energy and have started getting more exposure to renewables this year. A couple of the winds farms I have some exposure to are supposed to have some of GE's latest technology for synchronous condensers.
 

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czbrian, I'm not sure on what and why yours are being installed, I will make some guesses 'though. Your metering (revenue) is based on real power, whereas the limitations of the power lines are based on voltage and current. In AC, voltage and current are able (always are) out of phase. In the extreme example of out of phase, you can have the volts/amps so far out of phase that you can reach the transmission line voltage and heating (current) for little to no actual power flow. Long 3 phase lines do bad things to power factor. Wind is usually installed in somewhat remote/difficult areas making long lines necessary. A synchronous condenser can ensure that the site is operating in true power, and thus have the least capital cost for the extension lead back to the grid. Just a guess, but have read of a case study in Canada where a locale had an oil fired power station, and it was replaced by an underwater cable to the hydro. Due to the length of run, the cable capacity was limited by heat (current) to a certain power flow, and the voltage was depressed at the town end. By converting one of the turbogenerator sets to synchronous condenser (cut the turbine off), they were able to increase the power flow by 20%+, and keep the voltage stable at the town end.
 
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Even though a lot of this is beyond what I know, this is fascinating stuff; it's the future of power generation for the planet.
 
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Is the synchronous condenser basically functioning as a big flywheel (motor) to stabilize the voltage/current spikes, like a giant AC capacitor? Wonder if they could just put them at the wind farms to control spikes at the source? I have just enough knowledge to know what I don't know...
 

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bullwinkle, they are pretty big, and carry a lot of inertia so do provide some instantaneous power when the frequency drops...that's the inertial effect. But synchronous machines have an electro magnetic field applied to the rotor and a stator that is hooked to the grid, so they can do clever stuff like pushing the power factor around locally, and that flows onto and back into the grid.
 

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There could be a not inconsiderable death toll... http://www.smh.com.au/national/south-aus...928-grqpks.html
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Energy generation in South Australia is an issue that's never too far from the headlines. The state gets around 40 per cent of its energy from wind turbines, however in the current extreme weather the wind is too strong so the turbines aren't turning. In December, Premier Jay Weatherill hosted an energy crisis meeting after the state's commitment to renewable energy sparked a spike in the prices of fossil-fueled energy, in some cases by as much as 10 times. This July, the state government asked the owner of a gas-fueled power station to turn it back on. South Australia is connected to the National Electricity Market via an interconnector with Victoria, however it is believed this connection is currently down.
 
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Leaving aside the potential for tragedy, this is a fascinating watch. I can't wait to read the final report once it's all done and dusted. Plenty of theory right now, and all of it (if my interpretation is correct) appears to point to a lack of base load frequency control, but the Premier would tell me to stop playing politics and point out that this would happen anywhere else. Oddly enough it happened in Western Australia about 22 years ago, but for different reasons. That was a manual full grid shutdown to deal with a catastrophic fault and the re-start was relatively rapid and complete. We were out for about 6 hours from memory (after all, it was 22 years ago). I was in my second week home alone with chicken pox, so 6 hours without telly or a computer got pretty boring fast.
 

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Originally Posted By: Brad_C
Leaving aside the potential for tragedy, this is a fascinating watch. I can't wait to read the final report once it's all done and dusted.
Too true, it's a once in a lifetime event (well two if it's you)...I was watching the state come back in real time (not that it's completely back yet). *25MW of dieseels * which allowed 50-95MW of wind to come in (political move ???) * then 90MW of Simple GTs * then the gas thermals started coming in. (watching it in real time, wind had to be taken out to allow the state to be reconnected, was moving 60-90+MW over a few minutes)
 
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Originally Posted By: Shannow
Originally Posted By: Brad_C
Leaving aside the potential for tragedy, this is a fascinating watch. I can't wait to read the final report once it's all done and dusted.
Too true, it's a once in a lifetime event (well two if it's you)...
Oddly enough it wasn't the entire State in WA back in the 90's, it was only the South Western Interconnected System (SWIS). All the stuff up North is completely independent, so apparently the last full state blackout was Sydney in 64.
Originally Posted By: Shannow
I was watching the state come back in real time (not that it's completely back yet). *25MW of dieseels * which allowed 50-95MW of wind to come in (political move ???) * then 90MW of Simple GTs * then the gas thermals started coming in. (watching it in real time, wind had to be taken out to allow the state to be reconnected, was moving 60-90+MW over a few minutes)
The ABC report (which is necessarily dumbed down) stated the grid was kicked over first by a gas unit at Pelican Point. Not knowing the grid over there I can't interpret that further. Again, the reports seem to indicate it was a protected grid shut down by the inability to adequately load-shed to maintain frequency control. Surely that's directly a result of the lack of rotating machinery. Prior to the shutdown they quoted the wind units as supplying 70% of the states power due to the massive wind load available. I guess as bits of the grid start to pop for whatever reason, the sudden drop in load will see a spike in frequency from all the uncontrollable power sources forcing a disconnect as the only available option. A couple of good quotes at the bottom of one of the articles : Rushing to renewable energy targets puts sector's reputation at risk "Renewables are the future but, today, they present serious engineering problems. To deny that is to deny the science." "Those problems can be sorted in time, but rushing to a target to parade green credentials exposes the electricity network to a serious security risk and, in the long run, risks permanent reputational damage to the renewable energy cause." "The grid is being transformed, and that transformation needs to be managed sensibly, or the entire nation might go to black."
 
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Auckland Central had a major power cut in 1998 when 4 ancient cables supplying the CBD failed one by one. My shop was out for about 4 hours, but my industrial street was out for several days...I was on the corner, and power supply came from the other direction. The CBD was down for 5 weeks, there were huge generators sitting on the footpath all over the city. Lessons were learnt.
 
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."Again, these asynchronous machines provide no grid stability features other than power." Overall not a bad narrative for a management person. I could beat you up about your statement above. But m too lazy right now to type it all out. Technical sheit
 
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Could Wind Emerge As a Major Provider of Frequency Regulation?
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In an analysis, the National Renewable Energy Laboratory (NREL) showed that wind farms can quickly change their output to provide frequency regulation, a service grid operators rely on to ensure reliable power delivery. The finding could change how regulators, grid operators and wind-farm owners view wind energy. Today, natural gas power plants are often used for frequency regulation. They ramp up output to maintain a balance between power supply and demand, which keeps the grid’s frequency signal stable. Wind turbines can perform the same function by lowering their output, according to NREL wind analyst and study co-author Erik Ela. By changing the pitch of their blades slightly, wind turbines can make second-by-second curtailments that allow grid operators to keep the power supply and demand balance, he said. Normally, a wind farm operator would not want to curtail a wind farm, since they earn money based on how many megawatts-hours are sold. And because the fuel is free, wind power is typically tapped before other forms of power generation in wholesale energy markets. But in certain situations, a wind farm can earn more money by providing frequency regulation services, said Ela. "Because the grid values these services so much, [wind farms] can actually earn more money by curtailing and providing services than if they’re providing energy," he said.
 

Shannow

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SHOZ...per your quote...CAN (not DO, as there's a big difference). You can put in super duper controls and storage on Solar to do the same thing...but they don't, as the "cheapest" istallation (you know the ones that are "cheaper than coal") do no such thing. As I've said ad nauseum, WHEN renewables are required to do the heavy lifting, , i.e. when their disruptive technologies have pushed out traditional, then THEY will have to provide this regulation. For every 1,000MW of thermal, you will need 4,000MW of wind/Solar to harvest the same daily energy, and curtailment and storage to provide these essential functions. So the cost per MWh of the "cheap" technologies gets multiplies rapidly...that's all I've ever been saying.
 
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If the problem is hardware control and it can be dealt with. Europe requires frequency control of their wind farms. Regulation via rotor speed & pitch control [1] “Wind Generation Interconnection Requirements,” Technical Workshop, November 7, 2007, available at www.bctc.com/NR/rdonlyres/13465E96-E02C-...onWorkshop.pdf. [2] [North American Electric Reliability Corporation, “Special Report: Accommodating High Levels of Variable Generation,” April 2009, available at http://www.nerc.com/files/IVGTF_Report_041609.pdf.Review of the websites from TSOs (in Europe), reliability councils (i.e., NERC and regional organizations) and ISOs (in North America) suggest that there are no hard requirements regarding use of primary frequency control in wind turbines.There are soft requirements [1]: •BCTC will specify “on a site by site basis,” •Hydro Quebec requires that wind turbines be “designed so that they can be equipped with a frequency control system (>10MW)” •Manitoba Hydro “reserves the right for future wind generators” NERC [2], said, “Interconnection procedures and standards should be enhanced to address voltage and frequency ride-through, reactive and real power control, frequency and inertial response and must be applied in a consistent manner to all generation technologies.” [1] “Wind Generation Interconnection Requirements,” Technical Workshop, November 7, 2007, available at www.bctc.com/NR/rdonlyres/13465E96-E02C-...ionWorkshop.pdf [2] [North American Electric Reliability Corporation, “Special Report: Accommodating High Levels of Variable Generation,” April 2009, available at http://www.nerc.com/files/IVGTF_Report_041609.pdf Regulation via rotor speed & pitch control [15] Draft White Paper, “Wind Generation White Paper: Governor Response Requirement,” Feb, 2009, available at www.ercot.com/content/meetings/ros/keydo...ENT_draft.doc.. ERCOT says [1], “…as wind generation becomes a bigger percentage of the on line generation, wind generation will have to contribute to automatic frequency control. Wind generator control systems can provide an automatic response to frequency that is similar to governor response on steam turbine generators. The following draft protocol/operating guide concept is proposed for all new wind generators: All WGRs with signed interconnect agreements dated after March 1, 2009 shall have an automatic response to frequency deviations. …” [15] Draft White Paper, “Wind Generation White Paper: Governor Response Requirement,” Feb, 2009, available at www.ercot.com/content/meetings/ros/keydo...EMENT_draft.doc
 
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