TO: Any interested party.
FROM: Kevin
RE: Mr. Davis Presentation on the Almost Rolling Blackout of August 18, 1995.
DATE: August 25, 1995
Note: This was not the usual board meeting in that Mr. Davis did a fantastic job
of giving a special presentation on the big picture of what did and did not
happen last Friday, August 18. Keep in mind that rolling blackouts are relatively
rare in the United States. When they occur they are national news-type
stories. We can all be thankful this was only an exercise.
I. The Southwest Power Pool (SPP - See North American Reliability Council)
A. Reserves are determined politically - not by needs. Currently SPP’s planning reserve is 18 percent.
B. The Planning Reserve is determined by the surplus capacity of private
utilities.
1. Decisions are made by financial types - not by operating people.
2. Since 1972 power plant construction decisions are made based on the cost of
capital, not by need.
C. Regulation
1. Regulation is the amount of capacity required to serve your Control Area.
2. Control Areas are determined by choice - not by state and/or other boundaries.
a. Associated Electric Cooperative, Inc. (AECI) - loads AECI must have generation on line to serve.
b. West Plains - in AECI’s control area, but generated in Sikeston. AECI has generation on line any
way - in their control area.
D. Riding the Ties
1. All loads and resources go into the pool, with everyone responsible for their
own control area.
2. When a company uses all available capacity, they call on other utilities and
their reserve capacity.
3. A company can Ride the Ties for up to ten minutes, free of charge. During that ten minute period they
must make arrangements to pick up the deficiency. If they can’t find resources they must cut off customers (though, sometimes the rules are
bent a little).
II. The Week of August 14 in General
A. The SWPP was heavily loaded, with units in the south running day after day
with no break. Night-Time Temperatures were running too high to schedule even minor maintenance.
B. As a unit runs day after day without interruption the odds greatly increase
that it will develop tube leaks. A tube leak is a small hole in the Metal Boiler tubes containing steam (See Figure #1, hot Gases (see States Of Matter) from burning Coal flow over the outside of the tubes, creating steam. The boiler circulation
system is constructed of tubes, headers and drums joined in such a way that Water flow is provided to generate steam while cooling all parts.). When a plant
develops a tube leak operators will lower production, which lowers steam Pressure, in an attempt to keep the problem from worsening. As more plants are
de-rated it becomes more difficult to meet the system Peak Demand.
C. As a plant continues to develop tube leaks, or existing leaks worsen, the
operator de-rates the unit further and further. Eventually you reach the point
where the plant has to be shut down.
III. Thursday, August, 17.
A. Early on Thursday morning AECI went out and purchased all available Power. This is their common practice on hot summer and cold winter days when there
is any chance of a tight power market. Once they have control of the power
wrapped up they are in a position to sell at a premium if any other power
companies develop problems. Of course there are days when AECI loses money on the
deals they make, but over the course of a year they will come out significantly
ahead.
B. The table at the right shows several important things.
1. AECI’s system load is their Native-load, which is the firm requirements of a company. In AECI’s case that is the power sold to the G&Ts and Noranda.
2. AECI’s capacity on line was their coal-fired plants at Thomas Hill and New Madrid.
3. Hydro available is the generator units at Table Rock, Bull Shoals and other
Corp of Engineer (see Engineer - You Might Be One If ... ) Projects AECI has ready to go at a moments notice. Since a hydro unit can
come on line almost instantaneously it is considered Spinning Reserves. There are two basic types of reserves a power company has at its disposal.
Spinning reserve is ready instantaneously and includes hydro plants, units
actually spinning but not generating, and off-system sales made with the
understanding they can be dropped instantaneously. Spinning reserve in the form of off-system sales is a concept most people
around the state find hard to understand. Because of this AECI does not have to have idle generators standing by.
Cold reserves are coal-fired, Oil-fired and even combustion Turbines that take many minutes or even hours to get up and running.
4. Purchases are coming in from outside the system and sales are being made
outside the system. Sales are considered non-native load and can be interrupted
instantaneously.
5. At 2:30 p.m. AECI’s total source of power is the sum of capacity on line (2098), hydro available
(623) and purchases (1610) for a total of 4,331 MW. AECI’s total use of power was the system load (2,600) and sales (1,626) for a total
of 4,226. The amount leftover, 105, is called regulation. Regulation is available power AECI uses to handle instantaneous system
fluctuations. On a system the size of AECI’s, load can fluctuate 20 to 30 MW in a Second. This is because Air Conditioners around the state are turning on and off, Lights are being turned on and off, etc. When regulation goes negative, AECI is
riding the ties and has ten minutes to correct the situation. Computers handle regulation through a load-following scheme.
Thursday, August 17, 1995
Purchases 2:30 P.M. 330 P.M. Sales 2:30 P.M. 3:30 P.M.
Western
Farmers 50 50 IP&L 150 0
GRDA# 130 90 TVA 340 0
MSS 1000 0 GRDA 50 0
EPI 280 280 Columbia 19 0
MPS 100 0
LG&E 50 50
C. Basically, AECI had 1626 in spinning reserve (off system sales), which
normally would be very good considering their system Peak Demand is in the 2,700 range.
D. Within an eight minute period Thursday afternoon Entergy lost an 800 MW unit
and immediately stopped selling AECI 1,050 MW and the 600 MW unit at New Madrid
tripped off. AECI sales went to zero with 11 MW of regulation.
IV. Friday, August 18, 1995
A. The eighteen percent reserve of the SWPP was completely gone.
B. By law AECI had to prepare for the next catastrophe, the loss of the other 600
MW unit at New Madrid or the loss of the 630 MW unit #3 at Thomas Hill.
C. At approximately 8:00 a.m. Jim McNabb told Jim Jura they were in an emergency
condition. Jura immediately notified the G&T managers.
D. At approximately 10:00 a.m. McNabb notified the G&Ts and gave them the amount
of load they would be responsible for dropping. AECI had to prepare to lose
600 MW, the approximate size of New Madrid #2 and Thomas Hill #3. Sho-Me’s share was 150 MW and this amount would have been off from approximately 2:00
p.m. to 7:00 p.m.
E. There are two basic types of outages.
1. Loss of a Transformer, line, etc. This is usually pretty easy to handle.
2. Loss of a generator which creates a situation where the load exceeds available
generation.
a. The system becomes unstable and the results are erratic.
b. The system frequency will start falling.
c. There is a possibility that as the frequency falls a generator will try to act
like a motor. If that would occur the unit may try to run away. In this
situation the unit would increase its speed from 3,600 RPM to say, 10,000 RPM. At
this point the generator will self-destruct.
F. When an outage occurs that results in the system load being greater than the
system generation, load must be shed immediately. On Friday, the 18th, Sho-Me
would have only been given two to three minutes notice to start the rolling
blackouts.
V. How are communications handled?
A. AECI operating people forgot to tell their PR people. The PR people found out
when one of the cooperatives called in.
B. Press-type releases handled through AECI.
C. Frank Stork was ready with a Missouri-NET, Brownfield Network release.
D. Later in the day a state-wide peak alert was issued.
E. A press release about rolling blackouts will be issued after they occur.
Maybe.
VI. Other Utilities
A. Other utilities were hurting as bad or worse than AECI.
B. UE’s peak is approximately 8,000 MW. When word got out that AECI was in trouble
UE dispatchers got on the phone and begged AECI not to shut off 50 MW they were
buying at 100 mills (10.0 cents per kilowatthour).
C. Approximately one-half of Empire’s 700 MW peak was in jeopardy. Their own system was going to go down.
Instead of preparing for the blackouts their people were in their lawyer’s office in Jefferson City arguing about how to handle the potential liability.
VII. How did Sho-Me do?
A. According to AECI, Sho-Me was head and shoulders above the other G&T’s. This is something all of us should be proud of.