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Texas Rolling Brownouts
4

Texas Rolling Brownouts

Texas Rolling Brownouts

(OP)
What's the scoop with the rolling brownouts statewide on 2/2/11?

=====================================
(2B)+(2B)'  ?

RE: Texas Rolling Brownouts

(OP)
It took awhile to find anything in google. Here are a few tiny details:
http://www.wtaw.com/2011/02/02/rolling-outages-suspended-were-started-after-2-plants-shut-down/

Quote (AP):

Burst water pipes at two coal-fired power plants forced them to shut down, triggering rolling power cuts across the state, the lieutenant governor said Wednesday.  Lt. Gov. David Dewhurst said this is something that "should not happen."  Dewhurst said he was told that water pipes at two plants, Oak Grove and Sand Hill, forced them to cut electricity production. Natural gas power plants that should have provided back up had difficulty starting due to low pressure in the supply lines, also caused by the cold weather.  The lieutenant governor said the demand placed on the Texas grid was nowhere near peak capacity. He said he was frustrated by the situation.  The statewide electricity authority ordered cities across the state to start rolling power outages to cope with the crisis.

=====================================
(2B)+(2B)'  ?

RE: Texas Rolling Brownouts

We lost power 4 times throughout the day at work today in the Galleria area of West Houston.  First outage was right after 7:00 AM.  It was a fruitless day.  It typically took the network about 45 minutes to catch up once the power came back on.  And about that time another black out would occur.

I was sweating bullets when I got on the elevator to go to the parking garage at the end of my shift today.  I could just see being stuck on the elevator on the way out of the building.

There is a certain irony to my company being without power, but I can't be specific.

rmw

RE: Texas Rolling Brownouts

Oh, and by the way, ours wasn't a brownout, it was a pure and unadulterated BLACK out.

rmw

RE: Texas Rolling Brownouts

(OP)
West of Houston... plenty of power traders around there.  

http://www.dallasnews.com/news/community-news/dallas/headlines/20110202-ercot-may-initiate-more-blackouts-wednesday-night-thursday-morning.ece

Quote:

The planned outages, which lasted up to 45 minutes, were triggered when more than 50 power plants, including a few owned by Dallas-based Energy Future Holdings, stopped working Tuesday night because of the cold weather.

The Electric Reliability Council of Texas said 7,000 megawatts of generating capacity tripped Tuesday night, leaving the state without enough juice.
I have a suspicion there is a little more to the story than just a bunch of different power plants (50?) all had problems from the cold weather.

=====================================
(2B)+(2B)'  ?

RE: Texas Rolling Brownouts

(OP)
Underfrequency protection of generators is an interesting proposition where the goals of generator protection and system stability conflict.  I wonder if that played any role in this event.

=====================================
(2B)+(2B)'  ?

RE: Texas Rolling Brownouts

I wonder if we (the public) will ever know.

I wonder if we (those inside the industry) will ever know.

rmw

RE: Texas Rolling Brownouts

ePete,

Gas turbine prime movers usually have a very steep output roll-off as frequency drops because the compressor quickly loses its ability to deliver enough combustion air into the power turbine. They are far from an ideal machine to help the system ride through a major system disturbance. Any idea what the mix of generation is in that area - I suspect there is probably a lot of gas-fired plant.
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: Texas Rolling Brownouts

(OP)
Texas power as many know is separate from the rest of the US (except for small dc tie lines).

I know we have the typical sources: gas, oil, nuke wind.   Maybe someone  knows a link with a summary of power types.

I remember hearing we have the most wind of any state.   Wind I imagine is susceptible to being affected by weather, but I have no info to suggest that was the case.

I can see gas turbines are relatively susceptible to fluctuations in gas supply.  I know a lot of small gas turbines have gone in over the past years.  The older bigger gas plants used gas to fire boilers for steam turbines... all of those have the capability to switch between gas and alternate fuel and I'd think they would switch before a severe weather event that everyone knew was coming for days.

I did read on-line somewhere that in addition to the 7,000MW lost, there was already 12,000MW out for maintenance when things began.

=====================================
(2B)+(2B)'  ?

RE: Texas Rolling Brownouts

My bet is that most of the combined-cycle gas turbine plants in Texas are not equipped for cold weather with adequate heat tracing to keep critical lines and drains from freezing. In the design stage, the design ambient temperature was probably 2C or just above freezing. The plant owner's saved $1.5M-$2M on heat tracing that is not needed if it never gets cold.

Many of the combined cycle plants do not have bypass stacks on the gas turbines, another feature not considered necessary in the North American market. That means if the gas turbine is going to run, the Heat Recovery Steam Generator (HRSG) connected to it has to be able to take the exhaust heat. But the HRSG can't do that if its condensate lines and steam drains are frozen or already split open by the freeze. Or maybe the cooling tower froze up or the lube oil and generator cooler lines froze.

Another factor is the pipeline gas pressure is probably way down.  All houses and business's are using a lot of gas to keep warm.  The pressure may be below the minimum operating pressure at the plant. Or maybe the gas compressors' cooling water lines froze.  Backup fuel oil systems need auxiliary heaters to get the fuel to operating temperature.  Maybe the heaters are undersized for the actual ambient temperature.

When Mother Nature doesn't obey the Design Criteria, stuff happens.
 

RE: Texas Rolling Brownouts

What RCWilson is mostly true, but I heard a report yesterday that it was a couple of coal plants (might have been lignite) in central Texas that precipitated the crisis.  I can't recall their names now, but I did recognize them at the time.

What most plants in the coastal regions are not ready for is temperatues in the low '20's (F).  As RCW has pointed out, not a lot of stuff is heat traced because it is just not normally needed.

While the reports said burst water pipes, I suspect frozen instrument air lines.  It is not necessary either to have instrument air dryers that go much below 32F in this part of the world, so temps in the '20's will get the moisture in them every time.  But that is not so much based on reports as my own personal expernience in many of the typical power plant in the region, gas, coal or nuclear.

Plus the fact that other than one short cold snap last year, for the last several years, global warming has been so bad that it didn't even get cold enough to kill the mosquitos in the region, much less freeze a pipe or air line.

Add to that some of the ice load in the transmission lines in the northern portions of the ERCOT island, and the plants up there that are weatherized are not much help.

Add to that that at least two of the small DC ties outside the 'island' that EP mentions are into regions that have their own share of winter issues, there isn't much relief there either.

All of it adds up to a nasty surprise yesterday morning.  I don't think the emergency generator for our building was ready either.  I sat in the total dark (I was at my desk) for several minutes before the emergency lights kicked in.  I had not docked my laptop yet as I was waiting till the battery depleted completely so the screen was all the light I had.

rmw

RE: Texas Rolling Brownouts

Wind failure - I love it.  They just need to get the Texas Legislature out to a wind farm.

David Castor
www.cvoes.com

RE: Texas Rolling Brownouts

Please say it ain't so!  You mean that the wind isn't always at its max during peak demand periods?

Alan

RE: Texas Rolling Brownouts

(OP)
Interesting links.  

The reuters article points a finger at wind.   I was wondering how 50 plants could have gone down... now it makes more sense if it was a lot of small wind plants forced off by a common factor (ferocious winds) more ubiquitous than inadequate heat tracing.

The Pennenergy articles mentions no fault for wind but instead quotes a wind energy spokesman on how much wind was on-line helping in the time of need.

Which is closer to the truth I think will become clearer over time.

The Pennenergy article mentions someting about 15% of 7000MW out for maintenance initially... that might be in the neighborhood of almost 1200MW.  In contrast a Forbes columnist mentions 12,000MW out for maintenance initially:
http://blogs.forbes.com/christopherhelman/2011/02/03/rolling-blackouts-force-texas-to-import-power-from-mexico/

What's a factor of 10 among friends?

This was a pretty severe event both in terms of actual impact (statewide outages when people needed heat on the coldest day of the year) and potential impact (how close were we to losing a whole bunch of generators on underfrequency... we got to stage 3 which is last resort stage to prevent total system failue).

Given the severity, I was frankly amazed how difficult it was to find basic info about this event, but now I guess it is part of the deregulated competitive environment.  If info was released that allowed people to judge the near-term prospects for generation, it is insider information that gives some a competitive advantage/disadvantage in the electricity market.
 

=====================================
(2B)+(2B)'  ?

RE: Texas Rolling Brownouts

Thanks byrdj!

Alan

RE: Texas Rolling Brownouts

(OP)
"now it makes more sense if it was a lot of small wind plants"
should have been
"now it makes more sense if it included a lot of small wind plants"
i.e. the large number 50 is more easily understood when we consider it includes a lot of small plants. The wind plants explain the large number but not the total losss... wind loss reported as only 1700MW out of 7000 total according to Reuters.  Again I think it will become clearer over time ...I'm trying not to jump to conclusions yet.
 

=====================================
(2B)+(2B)'  ?

RE: Texas Rolling Brownouts

The article above makes a good argument for requiring an IQ test before one is allowed to publish.

RE: Texas Rolling Brownouts

Surely you can believe anything you read on the Internet, right?

Now to this thread.

The wind drop (and I an no big defender of wind) was on Tuesday evening per the article.  The rolling blackouts were Wednesday morning early and through the day.  I read another article on Energy Central that stated that on Wed wind contributed a significant amount of power helping keep it from being worse.  Actually, I kind of believe that because the locale where the wind farms are would then be behind the front when the winds would be strong out of the north.

Of course, I believe everything I read on the Internet then, don't I?

rmw

RE: Texas Rolling Brownouts

and there would not be any operating quirks (especially something like frozen lines on an out door unit) with 3 units during thier first few months of operation   

RE: Texas Rolling Brownouts

rmw - The "Tuesday" wind drop was in 2008.  

RE: Texas Rolling Brownouts

I'm really shocked that the wind power failed for Houston.

I thought that my mother-in-law moving there would sustain the region indefinitely.

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

RE: Texas Rolling Brownouts

wayne440:

Didn't you mean to say that the guy is an idiot?
 

Alan

RE: Texas Rolling Brownouts

I guess an "Individual Decidedly Ignorant Of Technology" could be a reasonable definition.

RE: Texas Rolling Brownouts

2
The following from scientific readers at www.wattsupwiththat.com about the Texas utility crisis, and the wind, coal AND gas distribution problems leading up to the rolling blackouts:

"_Jim says:
February 6, 2011 at 10:45 am (Edit)

I thought I might take this opportunity to post the time line as published in the Dallas Morning News titled:

Freeze knocked out coal plants and natural gas supplies, leading to blackouts
By ELIZABETH SOUDER, S.C. GWYNNE and GARY JACOBSON
Published 06 February 2011 12:56 AM

and do so under the Fair Use provision of the copyright act:

- – - – - – - – - – - – - – - – - – - – - – - –

Texas' power crisis timeline

Monday

Jan. 31 6:08 a.m.: ERCOT control room issues an operational message that says a cold front is approaching. Temperatures are expected to be 18 degrees or lower and remain near or below freezing, affecting half or more of major metropolitan areas, beginning at 9 a.m. Tuesday.

Tuesday

9:07 a.m.: ERCOT repeats its weather warning.

Before midnight: Gibbons Creek coal-fired generating plant near Bryan goes offline. It would be back up at midday Wednesday, off again late that day and up again early Thursday.

Wednesday

After midnight: Four of Luminant's coal-fired units in Central Texas go offline, as does one unit at a CPS Energy coal-fired plant in San Antonio. Officials decline to give specific times. The CPS unit is back up again by 11 a.m.

2:49 a.m.: ERCOT control issues an advisory because it doesn't expect to have enough power generation to meet demand. "Physical Responsive Capability" is below 3,000 megawatts.

3:21 a.m.: ERCOT e-mails that notification to Public Utility Commission Chairman Barry Smitherman and other top regulators. The advisory rates the probability of cutting off customers as "low."

3:30 a.m.: Real-time settlement point price for electricity in North Texas is $80.95 a megawatt hour. Some electricity in Texas trades on an electronic spot market, where retailers and big consumers can buy power each day from wholesalers.

3:45 a.m.: Settlement price jumps to $1,117.60 a megawatt hour. Prices typically spike on the spot market when supplies are tight.

5:08 a.m.: ERCOT control issues "watch" because Physical Responsive Capability is below 2,500 MW.

5:18 a.m.: ERCOT declares Level 2A of Energy Emergency Alert, meaning the grid has less than 1,750 megawatts of available reserves, a thin margin. ERCOT cuts power to customers who agreed to be part of an interruptible load program.

5:20 a.m.: ERCOT CEO Trip Doggett is in the shower when the emergency notification comes in. When he sees the notice, he calls Ken Saathoff, ERCOT's vice president of grid operations, to gather information. He then spends half an hour calling the three PUC members, the PUC executive director and one of the governor's advisers. He then drives to ERCOT's back-up control room in Austin and begins calling legislators.

5:43 a.m.: ERCOT declares a Level 3 EEA, the highest emergency level, meaning the grid is struggling to maintain system frequency at 59.8 Hz or greater. ERCOT instructs power line utilities to use rolling outages to cut demand.

5:52 a.m.: PUC chairman Smitherman gets a call from ERCOT's market monitor, Dan Jones. Smitherman, sick in bed with a sinus infection, doesn't answer. He takes a call from Doggett at 6:23, and heads to the backup control room, canceling a speaking engagement at Texas A&M University. He will spend much of the day coordinating with leaders of other state agencies to move more fuel to power plants.

6:14 a.m.: Austin Energy issues a news release about rolling blackouts statewide.

6:15 a.m.: Settlement price hits $3,001 megawatt hour.

6:54 a.m.: ERCOT issues a news release about rolling blackouts statewide.

8 a.m.: ERCOT asks Oncor to exclude natural gas compressor facilities from the rolling blackouts. Oncor asks for specific customers, but ERCOT isn't able to provide names.

After 8:30 a.m.: A coal unit at NRG Energy's Limestone plant near Jewett goes offline. It comes back just after 2 a.m. Thursday.

9:30 a.m.: ERCOT asks Oncor to exclude from the blackouts five counties in the heart of the natural gas production zone: Jack, Palo Pinto, Wise, Parker and Hood. Oncor does. Half an hour later, ERCOT asks Oncor to exclude areas west of Fort Worth from the blackouts, and Oncor complies. Oncor sends crews to repair lingering outages.

11:04 a.m.: ERCOT sends an e-mail to Atmos and other natural gas companies asking for the location of any facilities affected by the outages. Atmos' pipeline equipment runs on natural gas and is not affected.

Midday: Natural gas supply to Atmos' system drops off as gas well equipment freezes. Producers struggle to get workers to the field to repair the equipment in the cold. Atmos curtails supply to industrial customers between Interstate 30 and the Red River.

Luminant asks Atmos for a large supply of natural gas to fire up the Lake Ray Hubbard natural gas plant. Atmos declines, saying the request would shut off its residential customers and shut down part of Atmos' system, requiring weeks to return everyone to service. Atmos offers to move the large supply to Luminant's DeCordova plant in Hood County, but Luminant doesn't take the offer.

2:13 p.m.: ERCOT calls off rotating blackouts. ERCOT warns it may have to initiate another round of outages that evening or the following day, but it doesn't have to do so."   

RE: Texas Rolling Brownouts

Continuing from that discussion at www.wattsupwiththat.com:

"#
Mike Smith says:
February 4, 2011 at 12:50 pm (Edit)

Hi everyone,

Mike Goggin of the American Wind Energy Assn. is posting both here and at meteorologicalmusings.blogspot.com because he has so far avoided the questions I am posing to him at my blog. Yesterday afternoon (5:21pm), he agreed to provide the wind energy data for Wednesday night (2nd) and Thursday morning (3rd). After now FIVE requests, he still hasn't provided it. This is pertinent because, according to even the pro-wind people the PEAK load was Wednesday evening in Texas, not Wednesday morning! I want to see if wind can be a genuine contributor in extreme weather and load conditions.

I have stated, over and over, that if there was significant wind energy being generated during the time of the peak load I am open to revising my opinion. He keeps avoiding the issue.

There WERE reports of wind turbines doing down Wednesday morning during the blackout period, so my "guess" was correct: http://www.texastribune.org/texas-energy/electric-reliability-council-texas/the-rolling-chain-of-events-behind-texas-blackouts/

There are so many comments, here and at my blog, and so many emails I have personally received it is getting difficult to sort it all out. That said, let me try to reconstruct the "best case" for wind power. Even though there are 10,000MW installed, only 6,800 are possible at any given time due to transmission constraints. Mr. Goggin says that, at best, 3,900 were available from wind during the blackout period. If my math is correct, 39/68 = 57% availability, even though ERCOT had asked for maximum output.

If your car (which is about the physical size of the turbine itself) failed 43% of the time, I do not believe you would tout that fact as a "success."

Finally, valid points about coal plants going offline, etc. If you will read my original post, that very issue IS acknowledged at the end. But here is the problem: Wind energy requires "spinning reserve" from conventional power plants because of its inconsistency. My contention is that if we had simply build more nuclear (or coal) plants with the money spent on wind, the crisis (which interrupted power to hospitals!) could have been avoided.

Again, please come over to my blog if you would like to follow this, although I'm going to shut this topic down soon as there is only so much time and space I'm willing to devote to it.

Mike
#
someoneintheknow says:
February 4, 2011 at 1:27 pm (Edit)

Goggin fails to provide these numbers from Tuesday night to Wednesday morning. The wind output decreased by 2585 MW from 3 pm Tuesday to 6 am Wednesday. That is about the same capacity lost as the two coal plants that tripped offline Wednesday morning. Roark is correct that they were generating 3630 MW at 6 am Wednesday, but that was down 41% from Tuesday. There is a history of this happening in ERCOT: http://www1.eere.energy.gov/windandhydro/pdfs/43373.pdf

"

Note: I strongly recommend the the link to the pdf file about the earlier Feb 2008 ERCOT loss of wind power for its timeline, and the huge loss of wind power available in just minutes during that event, compared to the several hour loss of over 3500 Megawatt of potential wind power this year on Feb 2-3.  

Overall, demand grew from 25,000 Megawatt to just over 50,000 Megawatt in less than 10 hours as teh cold front moved through.  Demand then stabilized at over 50,000 Megawatt for the next two days.   
Theoretically available (nameplate capacity of wind power in the Texas system was 10,000 Megawatts, but apparently only 6800 Meg's can be connected to the grid.  (Boondoogle, anybody, about certain politically-connected "players" building more wind farms using tax money incintives faster than building (non-taxpayer-assisted power lines?????)  
Actual delivered wind power decreased during this time from 3800 Megawatts down to less than 1200 Megawatts, but the wind power associations have consistently not answered questions about how much was actually delivered when during the crisis - other than their initial claims of 3800 Megawatts during the highest wind period/lowest demand period early during the Feb 2 event.

RE: Texas Rolling Brownouts

This repeats my own submittal to that discussion on Feb 2 - Feb 3.  

"racookpe1978 says:
February 3, 2011 at 7:45 pm (Edit)

Too many numbers are not adding up to reality.

The Wind Energy groups are presenting (wild) claims, but have no graphs showing their delivery of actual electricity at actual times of day.

Worse, they appear to be claiming credit for theoretical power generated during the actual arrival of the cold front (very high winds for a short amount of time) but not for the long hours of much, much calmer winds but very cold temperatures over the long hours AFTER the cold front moved through west TX (the Lubbock are and high plains), central north TX (Dallas and Fort Worth, then east towards Texarkana, south to about Austin), nor the different winds but still temperatures that crossed San Antonio, then Houston then (a little) of deep south TX.

Until the wind energy groups release their specific hour-by-hour delivery of power for the full three days, I do not believe the press release represents reality. I could be wrong. But making a claim that "Wind power played a major role in keeping the blackouts from becoming more severe. Between 5 and 7 A.M. this morning (the peak of the electricity shortage) wind turbines was providing between 3,500 and 4,000 MW .." implies that they themselves do not know how power was provided to what region at what time. Further, the newer (largest) wind turbines today are 1 Megawatt at max power.

Varying just their claimed output between 3500 and 4000 Megawatts means that some 500 wind turbines dropped off line. (Or 1000 wind turbines suddenly and without control dropped 50% of their "claimed" nameplate power.) Gee. What reliability.

Now – There are several other troubling indicators. We see a power demand suddenly and rapidly rise (literally overnight) from a seasonal 25,000 Meg's to 50,000 Meg's of power needed. "Nobody" in Texas uses fuel oil for heating homes and workspaces (unlike the northern states where steam heaters, boilers, and home heating oil is more common) – everything is natural gas burners with electric fans to distribute the hot air, or electric-driven heat pumps, or electric resistance heaters.

There were (and still are) limits to how much natural gas can flow through the large pipelines that criss-cross the state. Nat gas shortages (the gas simply can't flow any faster@!@#$%!!!) will limit both home heating AND power plant delivery to power and gas turbine. (Few steam plants are natural gas driven any more – most were converted to coal between the 70′s and early 90′s.)

The "average" gas turbine plant is about 150 Meg's to 200 Meg's. A few new ones are starting construction at 250+ Meg's – but they aren't on line yet anywhere. The most common GT is two 150 Meg GT generators plus a third 150 Meg steam turbine-generator being driven by the waste heat recovery boilers from the GT exhaust. So, if I lose the two GT generators because they can't get natural gas, then the third steam driven unit drops off as well. Result? I lose not one 150 Meg generator, but three.

I don't accept the answer that only 2 large coal plants dropping out caused the rolling blackout either. We saw from the graph loaded above that power demand rose by 25,000 that night from seasonal averages. If the two coal-powered plants were 2700 Meg each – which might be the case, but seems grossly high; then we still need to account for the rest of the shortage. By the way, the largest nuclear plants are "only" 1100 Megawatts – so the claim that a single coal plant is 2700 Meg's needs to be scrutinized. (At least as carefully as the wind energy group's claims need to be verified.) An "average" older coal-powered plant is 250-300 Megawatts. The larger ("newer") coal-power plants built from the mid-70′s through the late 80′s was 500 – 800 Megawatts.

Did 50 large plants go out at the same time? (50 x 500 Megawatts?) Doesn't seem right.

Were the output from 50 "new" plants suddenly and unexpectedly needed in 10 hours? Yes.

Was wind power available to provide that power? No.

Was nuclear available? Yes. All nuclear plants in the TX grid were at 100%.

Could 150 large gas turbines make up the missing 50 large coal plants overnight? No.
1. They were not built -> Could not be built in Obama's regulatory environment, which demands ONLY wind power and does not permit solar.
2. The gas turbines that had been built for summer peak electrical loads were being repaired (Sweeny 2, Magic Valley 3, Magic Valley 2, etc.) or could not get natural gas.

Was the Texas "isolated" national grid to blame? In some ways yes, in some ways no. TX IS an isolated grid system with only AC-DC-AC conversion links at only a few places. (You MUST go back to DC to shift load between grids because of synchronous generation problems. Mess up the synchronous HZ of either grid and you blow up generators with billion dollar electric arcs at 48,000 volts apiece. ) The TX grid is larger than France, or Germany and Eastern Europe, or the UK grid, or the entire Scandinavian-Denamrk-Germany grid. "Hooking it" to the US national grids – Yes, Virginia, there are several US grids – is impossible, impractical, and BAD.

You cannot "ship" electricity further than 900 miles without losing over 70% to heat losses in the power lines. You "can" exchange voltage that far easily, just as you can get water pressure through a 1/2 garden hose 800 feet to a neighbor's garage. But open the faucet to get water "flow" (current x voltage, or power) through that little garden hose? You get a dribble.

TX is larger than most people realize: getting power across the state, getting natural gas across the state reliably is HARD. But getting the politicians – including the wind power propagandists – to deliver the truth may be much harder.

The questions remain:

Who was generating what amount of power where during those hours of the blackouts?
Who was generating what amount of power at what time?
How many plants had mechanical problems?
What were those problems? Frozen coal? Frozen 1/4 inch instrument lines? No gas pressure? Freezing cooling water lines? (The cooling ponds could not have frozen in that short amount of time.)"

The actual Texas power demand curves are ataggering as load ramped up over 25,000 Megawatts in just a few hours - while wind power delivered was ramping down by the equal of two or coal-powered conventional plants, and instantaneous power prices went sharply up:  

See this link from another WUWT writer:  

_Jim says:
February 3, 2011 at 11:53 am (Edit)

Graphical plot of power consumption under ERCOT's supervision for the last five days here in Texas:

http://oi51.tinypic.com/mkhd93.jpg

Data series begins 1-29-2011 and extends through 2-03-2011 1300 CST (Thursday)

Notes:
1) The cold front made it's way through the northern part of the state 2-01-2011 in the AM accompanied by multiple forms of precip
2) The rolling blackouts started somewhere around 2 or 3 AM on 2-02-2011 the next day when overnight temperatures in North Central Texas reached 12 deg F.

.
 

RE: Texas Rolling Brownouts

(OP)
Great analysis Mr Cook. I will have to study that for awhile.

=====================================
(2B)+(2B)'  ?

RE: Texas Rolling Brownouts

Thank you for your research and posting.   

RE: Texas Rolling Brownouts

@racookpe1978

TX grid bigger than France or Germany power grid? You're kidding, right? Rather similar to the UK.

May you grow up to be righteous, may you grow up to be true...

RE: Texas Rolling Brownouts

Everything is bigger in Texas.





 

David Castor
www.cvoes.com

RE: Texas Rolling Brownouts

and very important too!

May you grow up to be righteous, may you grow up to be true...

RE: Texas Rolling Brownouts

Size of the grid in terms of area covered:

Area of France?  Land area (excluding the island of Corsica) : 545630 sq km, or roughly 213,000 sq miles.   

Area of Germany? 137800 square miles

Area of Texas?   268820 square miles.   

RE: Texas Rolling Brownouts

A few years ago, a southern company bought into a large operation in a cold part of Canada. When the southern engineers arrived they had some issues with some hoardings protecting some equipment. When told that the hoardings were needed for protection in the winter, the reply was;
"We get winter in Texas too!"
With the hubris of experts (More than 50 miles from home) they decreed that the hoardings be removed.  
"We get winter in Texas too!" has become a buzz phrase in a cold part of Canada after the plants first shut-down due to cold weather in it's 30 years of operation.
I guess that we have differing expectations.
In Canada we strive to keep the plants going no matter what the weather.
In Texas, winter is short enough that some engineers believe that it's OK to stop for winter.
Now that Texas did get a winter, I wonder if any of the same engineers were involved with the plants that froze up.
Yes I know, these folk were not representative of the majority of the excellent engineers working in Texas.  

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Texas Rolling Brownouts

OK let's just pick France for instance, HV transmission system 100,000 km (62,000 mi), Texas HV transmission 41000 miles, record peak demand around 70000 vs 95000 MW in France.

May you grow up to be righteous, may you grow up to be true...

RE: Texas Rolling Brownouts

Texas megawatts are bigger than French megawatts.  This is well known.   

RE: Texas Rolling Brownouts

This maybe another classic one - politician lead power industry. Wind power is the god in the power generation development in North America. People did not learn the lesson happened in 2008. Politician do not want to hear that wind power can not be produced when the customers really need it.
In Canada, we have been told the same that we have to push wind IPP to the maximum capacity because of its Green.At the very beginning, we put 15-20% maximum penetration limit. It was removed later.
No surprise, all our big bosses are politician.
 

RE: Texas Rolling Brownouts

This has nothing to do with the non dispatchability of wind generation. That's just smoke and mirrors from people trying to deflect attention from their own incompetence and failings. The system was already in crisis when the wind output dropped. It reminds me of British Rail blaming the shutdown of the UK rail system on the "leaves on the line", or the channel tunnel rail link shutdown by the "wrong kind" of snow. You might as well blame the customers for switching the heating on.
Regards
Marmite

RE: Texas Rolling Brownouts

(OP)
http://www.chron.com/disp/story.mpl/business/energy/7427513.html

Quote:

While 8,000 megawatts was the peak outage, over the course of the day 82 power plants with a combined generating capacity of 11,000 megawatts went off line.

Forty percent of the plants that went down were powered by coal, 59 percent by natural gas and 1 percent by wind

....Many shutdowns were due to the failure of equipment monitoring different aspects of the plants, such as temperatures, pressures and water levels, as well as the failure of some control systems.

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RE: Texas Rolling Brownouts

I am still interested to know how the " wind power units ... produced at levels they were expected to" compared to nameplate ratings of the turbines. Since not much wind is expected after a cold front settles in, it might be a matter of living up to some low expectations.   

RE: Texas Rolling Brownouts

The cold front was still marching southward steadily when the blackouts occurred.  Strong winds behind a cold front are a typical weather condition in this area as I think they are in most.   This was a fairly strong front.  I don't have any doubts about the reports of wind performance and I am not a very big fan of wind otherwise.

rmw

 

RE: Texas Rolling Brownouts

Quote <You cannot "ship" electricity further than 900 miles without losing over 70% to heat losses in the power lines>


Wow...when did THAT happen?  I had NO idea that Texas losses are so much bigger than anywhere else.  I find it interesting that Portland General and Puget Sound Energy have had great success with scheduling energy from Colstrip, MT to their respective load centers...last I looked Colstrip was around 900 miles away!

Now, to be fair, I will agree that a 500 kV line with no intermediate stations (with compensation) isn't going to work so well after 300 or so miles...However, a claim of 70% losses (presumably on a transmission line) is a laughable statement.  A typical 500 kV line at 700 miles would have a resistance of around 22 ohms--hardly a scenario where 70% losses would occur.

Just for fun I took a look at a WECC model, and found that no 500 kV line had losses greater than 3%.

RE: Texas Rolling Brownouts

RE: Texas Rolling Brownouts

I was present for the event and a victim too, I might add.

tlrols,

Could this be a semantics problem?  RaCook goes on to comment about power being pushed (exchanged) rather than transmitted.

Now, in the interest of full disclosure, I am an ME.  We just make the stuff - the power that is - then the EE's transmit and distribute it after performing some magic on it out in the switch yard.

But the way it was explained to me years ago is that when power was sold by a gulf coast utility to say, New York for example, that the power wasn't sent from the gulf coast to New York, it was just sent to the next utility north which then sent an equal amount off of their system to the next utility north until some utility delivered an equal amount of power to New York.

Was that over simplified, or did I miss something.  And if it is an adequate description, was the power generated at Colstrip actually transmitted all the way to the west coast or just put on the grid there to be exchanged off the grid in Oregon?

I will still readily admit that about all I know about electricity is that it can kill you.  But I am still teachable.   So go for it if needed.

rmw

RE: Texas Rolling Brownouts

(OP)
Texas is an independent grid and not synchronized to the other grids.  The only power interchange from Texas to East US, to West US and to Mexico is via DC tie lines.  If you tried to put in just one or two long AC lines between Texas and East or West, it could cause stability problems during transients... the stability problems are related to the  to the real power limit of the line: real power transmitted thru an inductance is approx  P = |V^2|*sin(delta) / XL.  When delta hits 90, you can see it's sort of an unstable situation since the line starts losing capacity...causing rapid excursions similar to out of synchronization condition.   You'd need a whole lot of tie lines in parallel for stability.

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RE: Texas Rolling Brownouts

(OP)
As others have pointed out, the distance is not insurmountable...many other grids span much larger areas, but the system has evolved and grown without those rich interconnections, so establishing them now would require a lot of parallel lines.

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RE: Texas Rolling Brownouts

Pete,

What question are you answering?

There are small parts of Texas connected to grids other than ERCOT, so a power plant in Beaumont for example could "ship" power to New York City.

The 3 or so DC connections are fairly inconsequential with respect to the size of ERCOT and on the day in question, the grids that the DC connections are connected to were having their own issues and doubtful that they were a reliable resource for some stand-by power, but that is just a guess, not based on any facts.

I did wonder what the Tenaska units in Rusk County and Gateway were doing that day in that they have the ability to connect on an either/or basis to SWPP or ERCOT.  Either grid at the time was more than likely having the same struggles.

The grids you mention are larger, but they have units spread all over them.  Some units are sited specifically with respect to the grid's needs for real or reactive power as might be the case.  Others are sited for reasons of fuel, water access, etc.

rmw

RE: Texas Rolling Brownouts

(OP)

Quote:

What question are you answering?
racooke made some statements: "You cannot ship electricity further than 900 miles without losing over 70% to heat losses in the power lines".  I took the statement in context of explaining why Texas is  isolated... which is really the question/aspect I was addressing.

trols took exception with that exact same comment.

You responded to trols asking whether it was just semantics.  Perhaps you were addressing a different aspect (beats me), but when you stated "Was that over simplified, or did I miss something", I thought something very important was missing with respect to the reasons the ERCOT grid is separate... hence my response.

I apologize if I misunderstood your comment or told you something you already knew.

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RE: Texas Rolling Brownouts

Electricity CAN be transmitted over great distances using alternating current.  It is simply a matter of voltage and series/shunt compensation.  The assertion that the losses are 70% for a 900 mile long circuit is simply WRONG!!! However, would you build and operate a 900 mile long AC line with no intermediate stations--no.  This is what you do with HVDC lines.  AC lines should be looped into stations for compensation purposes at a minimum.

Texas, or more correctly speaking ERCOT, is not intercoonected to the rest of the United States (at least via AC links) for one simple reason...politics.  FERC has NO jurisdiction over the commerical electrical activities within the ERCOT footprint since ERCOT does not cross state boundaries.  In other words, the commerce clause of the US Consitution is not invoked, therefore, ERCOT (i.e. the State of Texas) defines the laws for doing commerical wholesale electrical business in Texas.  Call it a Texas thing.

Racooke's assertion is not correct.  You can operate an electrical system (note the word system) with the distance between any two points being several hundred miles.  In general, the very rough rule of thumb for transmission distance (without intermediate stations) is 1 kV per mile.  So, if you want to transmit power 500 kV, you would probably start looking at a voltage of at least 500 kV.  

In the WECC northern Mexico is electrically connected to northern British Columbia as well as eastern Montana.  Those distances are huge, approaching 1500 miles from Mexico into northern BC.  This system works just fine by the way, everyday...and it is much, much larger than Texas!

 

RE: Texas Rolling Brownouts

(OP)
I agree the distance is not a huge issue.  I understand that political factors have influenced the evolution of the current system.

I am also under the impression that providing an AC tie to the current system is not simple because of stability issues (you can't interconnect two big systems using only one or two long lines).  To make an ac interconnection work requires several parallel lines like 5 or 6 or more as I heard once (I can't find any reference).

To my knowledge that's why all the interconnections that have been added are DC (east, west and Mexico), and the new interconnection is also planned as DC:
http://en.wikipedia.org/wiki/Tres_Amigas_SuperStation

Am I way off base on this?

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RE: Texas Rolling Brownouts

Just because Northern Mexico is synchronously connected to Manitoba, Canada does that mean that power is transmitted from Northern Mexico to Manitoba, CA?

I'm not much up on WECC.  Beaumont, TX (the part of the Entergy system not in ERCOT) is electrically and synchronously connected to points way north of anything I know to mention in Eastern Canada, but I can't picture that they "ship" power that far even though I know that they sell power that far.  I have been in plants in the Entergy system when they took on the contracts to supply the power.  I can picture them putting power on Entergy's system (SWPP) and Entergy putting power on TVA at its NE corner on the way to points north and several grids later.

Isn't that what the term "wheeling" power means?

I'm not being argumentative, just asking.

rmw

RE: Texas Rolling Brownouts

(OP)
I agree, for the most part, power flows where it wants within the grid.  We can identify precisely the power flow along a given line. But in a grid, who's to say which MW is going to which load.    It is subjective, although there is plenty of bookkeeping that goes with it.  It is certainly possible with proper bookkeeping to put power in at one location and take power out at another location and treat it as a transaction.  Such transaction may or may not have a cost to the grid and may or may not be passed on the the people involved in the transaction.  

Setting the bookkeeping aside, it is in my understanding an unstable situation to interconnect two large systems with one or two weak (long) ac transmission lines because transients can force large power flow through those lines which can exceed their stability limits.   Most grids tend not to have that feature (2 large blocks connected by a weak connection of few lines), instead they are much more interconnected which generally improves stability.  

Sorry if I have brushed aside your issue. Two different issues. Both interesting.

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