Replies

First, Carry_Okie, you have a series of excellent observations and points. You may be right and I may have not understood what you were saying. Part of the problem is utility jargon.

I think (and I am speculating) that I understand what you are saying. I also think that maybe I can put a few things in perspective.

There is an article on what Alerts, Warnings and Emergencies mean. It can be found at the following locaction

Cal ISO White Paper PDF

From what I read and understand, the graphs that show the available generation from which you calculated "reserves" are not the "available generation" The graph of available generation from what I understand, has been "artificially reduced or lowered" by 3%. Actually the key definitions are as follows:

Available Resources*: The current forecast of generating and import energy resources available to serve the demand for energy within the California ISO service area. Total Resources is comprised of dependable generation less outages and unavailable OFs, plus the expected imported supply. Available resources is equal to Total Resources less a 3% reserve margin*. (Calculation is detailed below.)

A 3% reserve ensures the California ISO's ability to respond adequately to an unanticipated emergency. In order to protect the integrity of the Grid, the California ISO may declare a Stage Three Emergency when the system's Operating Reserver is forecast to be at or below 1.5% or less than the largest contingency within the service area (estimated to be 3%)..

So during the 3PM hour when the total generation (not discounted for reserves) exceeded load by only 694 MW or 1.6% of total generation, your question is why was only a Stage 1 Emergency declared?

I think we can both agree that probably they were on the ragged edge of a Stage 3 Emergency. The details also show that Total resources increased during the 4 PM hour. Things collapsed pretty quickly and it is clear that the ISO does not have a decent forecasting process.

According to the SOP's, should the ISO have declared Warnings the day before and Alerts the hour before? Yes! However, again, I don't think they have a good enough forecasting process to do that. Does this mean that the ISO shouldn't start a crash course in forecasting techniques. Nope, they should be able to do a lot better.

Could a single large machine fail and exceed 1% (435 MW) or 1.5% (652 MW) of the total generation which was 43504 MW? Yes, there are some large Nuc's that could have dropped that much load in a scram or turbine failure mode.

Does this mean that a Stage 2 or 3 Emergency should have really been called when a Stage 1 Emergency was called instead? That is an excellent question!

If that was your question instead of why wasn't a Stage 2 or 3 Alert called, I think you have a question that should be put to the Cal ISO. I would speculate that the answer they will give is that very early into the 3PM hour they placed an emergency order with the Bonneville Power Administration (or BC Hydro or other large power producer) to provide a significant enough increase in Total and available generation to know that they would not need to declare a Stage 3 Emergency during the 4 PM and later hours. None-the-less, I'll bet somebody was sweeting blood during the last half of the 3PM hour to make sure a power plant didn't go down somewhere in California.

Your point is very well taken, this probably was really on the ragged edge of a Stage 3 Emergency and you are right to raise the question of did somebody fudge the SOP's. I suspect that the answer is tied to the inacuracy of the ISO forecasts and that somebody form outside the region stepped in to help out, big time.

Carry_Okie;
You caused me to send an email to the communications director of the ISO. I'll let you know what I find out.

smccorkle@caiso.com
Dear Ms. McCorkle;

I was hoping that you could help me understand what happened on the afternoon of July 9th.

Specifically, by my calculations from your Ca ISO website for the 3 PM hour had total generation exceeding load by only 694 MW or 1.6% of total generation.

Why was only a Stage 1 Emergency declared? Should not a Stage 2 or Stage 3 Emergency been declared under ISO SOP?s?

I thought that the ISO definition for a Stage 3 Emergency is the lower of 1.5% of generation or a single contingency which ever is less. During the 3PM hour, 1.5% was only 652 MW, which is less than a number of large nuclear plant could have lost in the event of a scram or turbine trip. At 1.6% of generation the ISO was on the ragged edge of Stage 3 if the largest single contingency is not considered.

Therefore, in your explanation of why wasn?t a Stage 3 emergency declared, could you tell me what was considered the Stage 3 criteria and why. Also could you explain why a Stage 2 Emergency was not declared. Finally, could you explain how the ISO went form a Maintenance Warning to and Emergency without any Alerts being issues.

As a concerned Power Industry professional engineer and former Power Manager, I would like to better understand the California ISO and how it operates.

Sincerely,

Thank you for the clarification. The answer regarding my understanding is that I didn't understand the distinction between an Emergency (internal operating procedures) and an Alert (a request for public action). Had I been clear about that difference my question would have been BOTH. There is no doubt in my mind that the State should have both asked for public cooperation and taken action to hold delivery within safe operating margins. Perhaps they did the latter, but there is no indication of that on this thread.

It is now clear to me that socal_parrot's excellent graph represents 100% of available Resources or 97% of Available Generation (what I thought was meant by "Resources," namely what we make plus what we buy). That is certainly not as close as it seemed, but is clearly not an adequate margin for "business as usual."

If the margin below Capacity was but 1.6%, I don't think it shows that on the graph because it would show that the Reserve limit had been exceeded. If that is the case, then the situation I errantly surmised had in fact occurred and the question I raised (and you clarified) indeed applies:

Why only a Stage 1 Emergency?
Why only a Stage 1 Alert?

Thank you for your thoughtful post. There is investigatin' too due.

I got the following response to my email in post 89. I thought you might enjoy the doubletalk answer I got. I do think that the ISO broke their own rules on when a Stage 2 Emergency is declared last Tuesday. They may indeed be playing politics.

The operatives words seem to be ... Stage One provides authority to implement certain mitigating actions, outside of normal operating procedures, that the ISO may take to resolve the deficiency.

Mr (me)

You have described two separate responses to an operating reserve deficiency. One is a typical advisory message issued by one of the Western Electricity Coordinating Council (WECC) Reliability Coordinators to all WECC Control Areas. The other is implementation of the ISO Electrical Emergency Plan. One does not require the other.

The message cited below is a typical advisory issued by the WECC's Reliability Coordinator on the WECC network to all other Control Areas when a reserve deficiency is identified. Responsibility for this message rests with the WECC. This message does not require the ISO to issue a Stage One Emergency notice.

The ISO issues a Stage One Emergency notice in accord with its own Electrical Emergency Plan. Stage One provides authority to implement certain mitigating actions, outside of normal operating procedures, that the ISO may take to resolve the deficiency. Because we receive schedules from all generators in the ISO Control Area, constantly monitor their output, maintain logs to identify their performance limitations and revise load forecasts several times each day, we are uniquely able to identify the necessity of these mitigating actions to correct an operating reserve deficiency. If they are deemed unnecessary to correct the problem, the ISO may not issue the notice.

I hope this helps clarify this for you.

Regards.

Mitchell Ford
Lead Operations Analyst
California Independent System Operator

I didn't like the response so I sent a follow-up set of questions. They are as follows:

Mr. Ford

Thank you. Unfortunately your message did not clarify things for me. Perhaps my second e-mail to Ms. McCorkle confused the matter by my reference to the WECC system summary. If that is the case, I apologize.

Specifically, ISO Procedure E-508C on page 3 of 8 defines the situations under which Stage 1 and Stage 2 Emergency Notices are to be issued. Under the procedure, it states that a Stage 2 Emergency Notice is to be given when reserves are "currently or forecast to be below 5%." To me the word "currently" implies that an instantaneous or relatively short term value is implied in the determination of reserves, not an hour long average value or multiple hour average, and especially not that things should be OK next hour. If the ISO has another meaning for the word "currently" I would appreciate learning its definition.

In your message you state, "Stage One provides authority to implement certain mitigating actions, outside of normal operating procedures, that the ISO may take to resolve the deficiency." This implies to me that what you are terming "...mitigating actions, outside of normal operating procedures..." means that the California ISO may not have been strictly following the procedures within E-508C as I read it. If that is the case, I would like to know more so that I can properly understand the California ISO procedures during such a critical time.

Yes, I recognize that the WECC is a different agency than the California ISO. In the past I have participated in WSCC meetings in Utah so I am aware that WECC is different from the California ISO.

My question for last Tuesday was to find out to what level did the ISO reserves fall (as the limited information I have implies that they fell to less than a "current value of 5%.") So I am specifically asking for the lowest reserve value on Tuesday. If the answer was a number below 5%, (which all information I have appears to be the case) then I would like to know why an E-508C Stage 2 Emergency Notice was not declared by the ISO.

If I can clarify my "Tuesday questions" further, please do not hesitate to ask me to explain.

In summary, I would like to know:

(1) the lowest reserve value for last Tuesday,
(2) how that value is calculated,
(3) if "current reserves were below 5%" why a Stage 2 Emergency Notice was not called,
(4) if the ISO was implementing mitigation that would assure that reserves would not go below 5%, what were those mitigation measures.

For last Wednesday, the ISO declared a Stage 2 Emergency Notice and required certain loads to be interrupted. For Wednesday, I would like to know the lowest reserve value for last Wednesday (there appear to be four clock hours in which reserves may have been "currently" low or "forecast" to be low.). I would further like to know how the value was calculated, if the current or forecast value of reserves was below 1.5% why a "Stage 3 Emergency Notice" or "Stage 3 Emergency Notice of Load Interruption" was not declared, if there were some mitigation measures implemented by the California ISO to keep reserves above 1.5%, what were they.

Thank you

me, P.E.