Tuesday (two days ago):
[KHOU] Texas now under level 1 emergency; Residents asked to conserve more electricity
HOUSTON – ERCOT put out a notice at 2:30 p.m. Tuesday afternoon saying the state’s reserve levels dropped below 2,300 megawatts, putting into effect an Energy Emergency Alert level 1.
“We are requesting that consumers and businesses reduce their electricity use during peak electricity hours from 3 to 7 p.m. today, particularly between 4 and 5 p.m. when we expect to hit another peak demand record,” said Kent Saathoff, vice president of system planning and operations. “We do not know at this time if additional emergency steps will be needed.”
More blackouts this afternoon (i.e. Thursday):
[Reuters] Texas grid warns of rolling outages on heat
Extreme heat and soaring power demand may force the Texas power grid operator to impose rolling outages on Thursday afternoon to prevent a wider blackout as residents struggle with a record-breaking heatwave.
The Electric Reliability Council of Texas, ERCOT, moved to curtail power to some industrial customers Thursday afternoon as a way to boost surplus power to keep residential air conditioners running over the hottest part of the afternoon.
The state -- broiling under a relentless streak of 100-plus degree temperatures and drought -- has set three power consumption records this week, straining power plants.
And where are Texas' 9,727 MW of wind turbines in this crisis? Out to lunch. One picture says it all (note the distinct scales):
http://www.ercot.com/gridinfo/generation/ (August 2011)
Note how wind power is strongly anticorrelated with the afternoon demand peak! Wind power "reliably fails" whenever electricity is most needed.
The American Wind Energy Association is here to give us their "spin" on the situation:
[AWEA blog] Wind helps meet new Texas record for electricity demand
Commented American Wind Energy Association Manager of Transmission Policy Michael Goggin, "At a time when the extreme heat prevailing in Texas is pushing the utility system close to its limits, wind generation is making a valuable and much-needed contribution to system reliability."
At the risk of revisiting the obvious, these were the operating power levels of Texas' four nuclear power reactors over the same week, according to the NRC:
| power reactor | capacity (net) | 7/27 | 7/28 | 7/29 | 7/30 | 7/31 | 8/1 | 8/2 | 8/3 |
| Comanche Peak #1 (PWR) | 1,209 MWe | 100% | 100% | 100% | 100% | 100% | 100% | 100% | 100% |
| Comanche Peak #2 (PWR) | 1,158 MWe | 100% | 100% | 100% | 100% | 100% | 100% | 100% | 100% |
| South Texas #1 (PWR) | 1,280 MWe | 100% | 100% | 100% | 100% | 100% | 100% | 100% | 100% |
| South Texas #2 (PWR) | 1,280 MWe | 100% | 100% | 100% | 100% | 100% | 100% | 100% | 100% |
| 4,927 MWe |
[NRC] Power Reactor Status Reports for 2011
[IAEA] United States of America: Nuclear Power Reactors - Alphabetic
Update (8/11): One week later, more of the same:
Informative article in WSJ:
I'm sorry uvdiv, but that's a horrible graph. Not only is the scale off, the left hand scale with total grid demand also has no 0 axis (cut axis on 20,000 MWe). That's one of the worst graphs I've ever seen. Close to propaganda. Now I can get that, in order to compare the correlation, the right axis must be smaller, but using inconsistent axe-cutting is, well, axe-grinding stock market dishonesty. Grid demand in ERCOT is a lot more stable than this graph would make you believe! Its always between 34 and 68 GWe.
ReplyDeleteIf ERCOT doesn't even know basic graph-lore, its hardly a suprise that they've gotten themselves into this mess; the graph makes just as much sense as wind turbines.
Cheers but don't drink to that graph, Cyril.
Cyril, to be fair to Ercot, that graph is the last in the pdf, after a series of other graphs that are more like you (and I) would prefer.
ReplyDeletePick any pdf from the "ERCOT Wind Integration Report August 2011" zip file at uvdiv's link.
Too bad ERCOT only provides this info in running 7-day histories in a pdf, and not in a historical .csv or excel format.
ReplyDeleteThe comments on the AWEA blog post are quite incredible. Firstly, there is a pro-wind post that cautions trumpeting the 8% figure because it's really low. Next, another pro-wind commentator accuses the last one of being hired by the fossil fuel industry.
ReplyDeleteThis, in spite of the fact that the post 2,000 MW, which is more than the 8% "reliable" 800 MW, which it just fell below, to 300-something MW early morning 8/3.
So the message was "yay, we are delivering more power than our assured output", even though they drop below the assured output about half of the days in the week shown in the graph here. And then someone cautions that the assured output is too low and doesn't look very good because of that. And someone else tells that person they work for the fossil fuel industry.
It doesn't actually matter what scale the y-axes have. The message is the same, that is power generation by wind turbines is cyclical and doesn't necessarily correlate with the demand for power.
ReplyDeleteERCOT says:
ReplyDeleteWind generation contributed approximately 2,000 MW during the peak hour.
http://www.ercot.com/news/press_releases/show/416
With wind power generating 2000 MW at the peak power demand. That means the the utility saved 4000 MW of fossil fuels from being burned.
Saving fossil fuels from being burned everyday is pretty good money in the pocketed for the utility.
Too bad ERCOT
Ok, fair enough on the comments... but he does point out the different scale... also, to me, the way this looks is actually good for wind... at first glance anyway... it makes it look like a huge percentage of the demand is being met by wind... until you look closer
ReplyDelete@Cyril -- I agree that the axis offset (non-zero) is bad presentation. But the different scales are clearly necessary, since the two datasets are of very different magnitude. On a common scale, the wind data would be flat and hard to compare. It's more important (I think?) to depict the fluctuations and their timing, not the relative size of wind power (which everyone should get by reading the labels anyways).
ReplyDeleteI get the reasoning of using different scaling for the second Y axis. It's the cutting of the graph that's true 'graph-junk' here, as it is applied inconsistently between the two Y axis. The total grid demand is cut but the wind output is not! Now, if they cut the second Y axis the same as they did the first, it wouldn't be half as terrible. But the way they do this graph makes wind looks double way better than it is. What people miss here is the consistency of demand. They've made the demand look almost as inconsistent as wind, which is nonsense: this type of demand matches very well with baseload. It bothers me that people make graphs like this. It could be sheer stupidity, ie letting the computer zoom in on auto mode and then use that standard setting.
ReplyDeleteDon't get me wrong though Uvdiv, great work on this post. It's just that this graph is screaming the label "how not to make a graph". This is what you see in school books as typical bad examples! Anyways, just saying, I'll stop ranting and wining about it now...
By the way, the link to Ercot doesn't work anymore (for me at least). Perhaps they're trying to cut power by shutting down their server capacity? ; )