IA-98-272, Forwards Summary Assessment of Capacity Situation for Mid-American Interconnected Network.Combination of Projected Unavilability Likely to Result in Electricity Supply Shortages,Particularly in Listed Areas
| ML20236S670 | |
| Person / Time | |
|---|---|
| Issue date: | 06/12/1997 |
| From: | Calvo J NRC (Affiliation Not Assigned) |
| To: | Sheron B NRC (Affiliation Not Assigned) |
| Shared Package | |
| ML20236S659 | List: |
| References | |
| FOIA-98-272 NUDOCS 9807270161 | |
| Download: ML20236S670 (14) | |
Text
.- .
g V FROM: .
Jos6 A. Calvo, Chief (Original /s/ by J. Calvo)
Electrical Engineering Branch
! Division of Engineering
SUBJECT:
MID-AMERICA INTERCONNECTED NETWORK (MAIN) -- 1997.
( SUP9tER CAPACITY ASSESSMENT Attachment I presents a summary assessment of the capacity situation for the Mid-America Interconnected Network (MAIN). The combination of the projected l unavailability of 4,700 to 6,500 MW of nuclear generation and limited j transmission import capability is likely to result in electricity supply-shortages, particularly in the Northern Illinois, Wisconsin-Upper Michigan, and South Central Illinois Subregions.
MAIN is prepared to implement significant load management actions including 4 controlled interruption (rotating blackouts) of loads. These actions should make available sufficient capacity margin to ensure that the backbone of the transmission network remains energized following major disturbances, and barring unforeseeable circumstances, this would ensure the availability of offsite power to the nuclear power plants. i
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In view of the sensitive situation in the MAIN Region and the high potential for voltage perturbations in the electric grid that may lead to the f loss-of-offsite power to nuclear power plants, EELB suggests that the NRR Division of Reactor Projects III and IV and/or the Region III communicate l . with the licensees to assure that precautionary measures are being taken and
! are prepared to mitigate safely the consequences of the loss-of-offsite power l including the prompt restoration of it if such an event should occur. Further l / details on these recommendations are presented in Attachments I and 2.
l Attachments:
- 1. MAIN 1997 Summer Capacity Assessment - Summary
- 2. MAIN 1997 Summer Capacity Assessment - Background
- 3. Table - Scenario 1, "4,606 MW Total Inoperable Capacity"
- 4. Table - Scenario 2, "6,125 MW Total Inoperable Capacity" l S. Table - Scenario 3, "7,179 MW Total Inoperable Capacity" l
L CONTACT: Narinder K. Trehan, NRR/DE 415-2777 DISTRIBUTION w/ attachments
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- MID-AMERICA INTERCONNECTED NETWORK (MAIN)
, 1997 SUMMER CAPACITY ASSESSMENT .
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SUMMARY
Mid-America Interconnected Network (MAIN) is one of the ten regional councils under the North American Reliability Council (NERC). MAIN is a voluntary association of electric utilities, encompassing subregions of Northern Illinois (NI), Wisconsin-Upper Michigan (WUMS), Eastern Missouri (EMO), and South Central Illinois (SCIL).
The MAIN Region does not have facilities for regional control of generating capacity or major switching stations rather there are 13 control areas and each controls its own generating capacity in accordance with procedures set in the MAIN operating guides and procedures established by NERC. The MAIN Coordination Center, located in inabard, Illinois, ensures that the region will meet its load requirements with the interconnected network. To accomplish this, the Center coordinates the scheduled outages of transmission and generation facilities, provides infomation regarding generating capacity reserves, analyzes system operation, and assists members during critical
' conditions. In the event of an emergency, such as a severe generating shortage or the sudden loss of power in a neighboring region, individual control areas of MAIN have the authority to shed load independently. The control areas in the MAIN Region are operated as separate entities.
During severe generation shortage situations, MAIN has an Emergency Load Conservation Procedure in place that implements actions such as voltage reductions, exercise interruptible demand agreements and customer appeals to
( reduce the use of electricity to ensure that the load demand matches the available power generation. When all load demand side actions have been exhausted and there is still a need for further reduction, load shedding or controlled rotating blackouts would be used in MAIN only when it is necessary to protect against a widespread failure of the power system.
MAIN has established a reliability goal of I day in 10 years for loss of load.
The-installed generating capacity, which includes non-utility generators in MAIN, is approximately 52,000 MW. There are 16 nuclear power plants that provide about 25 percent of the total generation of the MAIN Region.
The MAIN Region, particularly the Northern Illinois, Wisconsin-Upper Michigan, r
and South Central Illinois Subregions will need to take extraordinary measures this summer to ensure an adequate supply of power to meet expected load demands. This situation is due mainly to the expected unavailability of l 4,700 to 6,500 MW of nuclear generation in Northern Illinois rnd Wisconsin.
t ATTACHMENT 1 k l L
MAIN has analyzed a range of capacity scenarios that consider the 1
- unavailability of power, mostly nuclear generation, during the summer of 1997.
In the most optimistic scenario (Zion I and 2, LaSalle 1 and 2, and 372 W of 3 fossil generation out of service) and with full-responsibility firm '
( transactions included (purchase of imported power), the capacity margins in v' MAIN during peak periods could be as low as 11.5 percent. In the most l pessimistic scenario (Zion I and 2, LaSalle 1 and 2, Point Beach I and 2, Kewaunee, Clinton, and 465 W of fossil generation out of service), the ) l capacity margin in MAIN during peak periods could be as low as 6.6 percent. 1 In both scenarios, the worst deficiencies are in the Northern Illinois l
. Subregion (2.6 percent capacity margin for the Subregion). The utilities of MAIN are taking extra measures to deal with these situations. .
t Utilities in the three affected Subregions are contracting for supplemental firm capacity with firm transmission service to replace the i unavailable generation.
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- The actual and potential outage, particularly, of nuclear generating i
units, create voltage-level control problems as a result of the unavailability of tiie excitation systems for these units to control MVAR.
Therefore, significant additions of reactive support are being installed i to ensure that adequate transmission system voltage levels are maintained at all times. NI and WMS are adding about 3,000 MVARs. l The transmission network capability both within and exterior to MAIN is not designed to import electricity into the Region at the levels expected to be necessary this summer. Implementation of several transmission operating procedures is expected to be required to import sufficient replacement resources even for the optimistic scenario.
i MAIN appears to be ready to meet the challenges for 1997 summer operating i
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conditions which include ensuring that the backbone of the transmission network remains energized following the major grid disturbances, and barring unforeseeable circumstances, this would ensure the availability of offsite power to the nuclear power plants.
Recommendations Despite the extensive preparations and planning by MAIN and its members, the combination of generator unavailability and limited transmission capability coupled with unanticipated circumstances such as extreme weather conditions j could result in electricity supply shortages.
In view of the sensitive situation in the MAIN Region and the high potential for voltage perturbations in the electric grid that may lead to the
. loss-of-offsite power to nuclear power plants, EELB suggests that the NRR Division of Reactor Projects III and IV and/or the Region III should communicate with the licensees of nuclear power plants operating in the MAIN Region to inform them that discretionary emergency diesel generator maintenance should not be scheduled for June through late September 1997.
This action would help to maximize the number of emergency power sources available in the event of a loss-of-offsite power.
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i The Division of Reactor Projects III and IV and/or the Region III should also comunicate with the licensees to request that operators of nuclear power plants should place special emphasis on refreshing their knowledge of procedures related to response to loss-of-offsite power to the plant. In addition, the plant should closely comunicate with the corresponding MAIN
-Region control area to be aware of particularly critical situations as they occur. {
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MID-AMERICA INTERCONNECTED NETWORK (NAIN) 1997 $UMMER CAPACITY ASSESSMENT BACKGROUND Following the 1965 blackout in the northeastern United States and southeastern Ontario, Canada, electric utilities formed the North American Reliability
-Councti '(NERC) in 1968 to promote the reliability of the electricity supply in North America. NERC consists of ten regional reliability councils and one affiliate, whose members account for virtually all the electricity supplied in the United States, Canada, and a portion of Baja California Norte, Mexico.
The members of these councils are from all segments of the electricity supply industry, including investor-owned, Federal, rural electric cooperative, State / municipal, provincial utilities, independent power producers, and power marketers.
NERC develops planning principles and guides that describe good practices for bulk electric system planning. The regional councils, subregions, pools, and individual systems, w)ich have the primary responsibility for the reliability i
of bulk electric supply, develop the following: q
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Reliability criteria applicable to their region or area for use in planning and constructing bulk electric systems.
Criteria dealing with the application and coordination of automatic underfrequency load shedding, load forecasting considerations, .and system parameter recording.
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- Arrangements to ensure that interregional effects on reliability are reviewed and encouragement of regional planning coordination.
The planning principles and guides developed by NERC, along with criteria developed by the regional councils, serve as a basis on which the utility industry performs self-monitoring in providing a reliable supply of electricity.
One of the ten Regional Councils is the Mid-America Interconnected Network l (MAIN), which is the subject of this report.
l llMH MAIN encompasses four subregions: Northern Illinois (NI), Wisconsin-Upper Michigan (WUMS), South Central Illinois (SCIL) and Eastern Missouri (EMO).
ATTACHMENT 2 1
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- The MAIN Coordination Center located in Lombard, Illinois ensures that the
' region will meet its load requirements with the interconnected network. To accomplish this, the Center coordinates the scheduled outages of transmission and VMeration facilities, provide information regarding generating capacity
( reserves, analyze system operation and assist members during critical conditions.
The MAIN Region does not have facilities for regional control of generating i
capacity of major switching stations rather there are 13 control areas in MIN and each controls its own generating capacity in accordance with operating guidance and procedures established by MAIN and NERC. In the event of an emergency, such as a severe generation shortage or the sudden loss of power in a neighboring region, individual, control area of MAIN have the authority to l shed load independently. The-control areas in the NAIN Region are operated as separate entities.
MAIN and its four subregions has reported the, following installed capacity for the month of June 1997.
Canacity Resources in MW E gg1 jgt gg gig iTotal)
Owned Capacity 22,307 10,778 10,509 8,072 51,666 Independent Power 37 253 47 2 339 Producers TOTALS: 22,344 11,031 10,556 8,074 52,005 The actual capacity resources available to meet load demand projected during this summer for three scenarios of inoperable capacity (which are reasonably expected - see definition of " Adequacy" Summer 1997 Capacity Assessment section)of this report.are addressed under MA The total nuclear generation capacity available in the States of Illinois and Wisconsin is approximately 13,620 MW, which represents about 25 percent of the total installed capacity resources of approximately 52,000 MW assigned to MAIN. A breakdown of the nuclear generation capacity is presented below.
Illinois Station / Unit $117 fMW) 9MD8E Braidwood 1 1,090 Commonwealth Edison Co.
Braidwood 2 1,090 Commonwealth Edison Co.
Byron 1 1,090 Commonwealth Edison Co.
Byron 2 1,090 Commonwealth Edison Co.
Clinton 1 930 Illinois Power Co.
Soyland Power Cooperative, Inc Dresden 2 773 Com anwealth Edison Co.
i Station / Unit Size fMW) Owner Dresden 3 773 Commonwealth Edison Co.
. LaSalle 1 1,048 Commonwealth Edison Co.
f LaSalle 2 1,048 Commonwealth Edison Co.
(' Quad Cities 1 577 Commonwealth Edison Co.
MidAmerican Energy Co.
Quad Cities 2 577 Commonwealth Edison Co.
MidAmerican Energy.Co.
Zion 1 1,040 Commonwealth Edison Co.
Zion 2 ,
1,040 Commonwealth Edison Co.
Total ' 32,166 Wisconsin Kewaunee 520 Wisconsin Public Service Corp.
Wisconsin Power & Light Co.
Madison Gas & Electric Co.
Point Beach 1 493 Wisconsin Electric Power Co.
Point Beach 1 441 Wisconsin Electric Power Co.
Total 1,454 ;
t GRID OPERATING CRITERIA AND SPECIAL OPERATING PROCEDURES f NERC addresses electrical system reliability by considering two basic and t functional aspects of the electrical system -- adequacy and security.
Adecuacy: The ability of the electric system to supply the aggregate electrical demand and energy requirements of the customers at all times, taking into account scheduled and reasonably expected unscheduled outages of system elements.
Security: The ability of the electric system to withstand sudden disturbances ,
such as electric short circuits or unanticipated loss-of-system elements. l MAIN's operating criteria state that the power pool should, at all times, have i sufficient generation available to meet demand plus maintain an. operating reserve large enough to cover major disturbances such as the sudden loss of a major generating or transmission facility. These criteris address both the adequacy and security aspects of electric system reliability.
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MAIN will implement their " Emergency Load Conservation Procedure" whenever !
operating reserves are running low due to insufficient available generation.
This would help preserve a portion of the required reserves and thus would ensure uninterrupted service to continue for most customers throughout the l
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- MAIN Region. Typical sequence of Emergency Load Conservation Procedure actions that can be taken by MAIN and member utilities during a generating' shortage are listed below.
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- Bring spinning reserve from peaking units and all fossil-fuel generators to maximum output. ;
Purchase emergency power from neighboring regions.
Implement region-wide five-percent voltage reduction. l
- Curtail coal handling loads.
Request neighboring spinning reserve.
Request load curtailment by utilities.
Request outputs above environmental limits.
Exercise interruptible demand agreements.
Make radio and TV appeals to the general public for voluntary conservation.
While these actions normally apply to MAIN as a whole, they can be selectively 1 implemented in any one of the 13 control areas.affected by a generating I shortage. In the event that these actions are not sufficient to keep operating reserves from being further depleted, load shedding would be required. When the transmission system cannot deliver sufficient generating
[ ' capacity to meet the load demand, system security will be maintained by disconnecting load as necessary to balance the remaining demand with the generating capacity that the transmission system can deliver reliably at any particular moment.
Load shedding or controlled rotating blackouts would be implemented by MAIN :
member utilities after the other load demand side actions have been exhausted.
Services would be cut off to groups of customers on a rotating basis so that ,
no one group would be out of electricity for a prolonged period. Load ;
shedding or controlled blackouts would be used in MAIN only when it is necessary to protect against a widespread failure of the power system. MAIN l has established a reliability goal of I day in lo years for this loss of load.
MAIN REGION SUMMER 1997 CAPACITY ASSESSMENT l The Mid-America Interconnected Network (MAIN) Region, particularly NI, WUMS,
- 'and SCIL Subregions, will need to take extraordinary measures to ensure an
' -adequate supply of power to meet expected load demands while also ensuring the security of the electric system. This situation is due mainly to the expected unavailability of 4,700 to 6,500 MW of nuclear generation in Northern Illinois and Wisconsin. The following discussion addresses a range of capacity deficiency scenarios.and resulting capacity margin for each scenario during each summer month in 1997 for each of the four subregions of MAIN.
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, Supply Adequacy MAIN has analyzed a range of capacity scenarios that consider the unavailability of power, mostly nuclear generation, during the summer of 1997.
.These scenarios are as follows:
- Scenario 1. The expectation is that only two units at both the Zion (2,080 W) and LaSalle (2,096 W) nuclear generating stations and one fossil steam unit (372 W) will be out of service this swmer.
- Scenario 2. In addition to the units identified in Scenario 1, assumes that-two additional nuclear units, Clinton (930 MW) and Point Beach 1 ,
(493 W for serv) ice this summer.and one additional fossil steam un1t (96 MW
- Scenario 3. In addition to the units identified under Scenario 1, assumes that four additional nuclear units will remain out of service during the summer period. These units are Point Beach I and 2 (934 MW),
Kewaunee (520 MW), and Clinton (930 MW). Also, two additional fossil units (93 MW) are assumed to be unavailable.
In the most optimistic scenario (Scenario 1), and with full-responsibility firm transactions included ~(purchases of imported power), the capacity margins in MAIN during peak periods could be as low as 11.5 percent. In the most pessimistic scenario (Scenario 3), the capacity margin in MAIN during peak periods could be as low as 6.6 percent. In both scenarios, the worst deficiencies are Tii~the NI Subregion (2.6 percent capacity margin for the Subregion). Further details about the resulting available capacity margins for each of the four MAIN Subregions are presented in Attachments 3, 4 and 5.
( Utilities in the three affected Subregions are contracting for supplemental firm capacity with firm transmission service to replace the unavailable generation.
Transmission System Limitations The transmission systems in MAIN were designed to deliver the generation resources to the demand centers as an integrated system, with generating' units supportin However,the g the voltage network integrated and adjusting flows designed was never on the transmission system. into to import electricity the Region at the levels expected to be necessary this summer.
Therefore, use of several omergency transmission operating procedures is l expected to be required to import sufficient replacement resources even for the optimistic Scenario I situation. Incremental transmission import capability is generally adequate for Scenario 1, but mostly inadequate to import sufficient replacement resources during peak demands for Scenarios 2 l and 3.. However, the impact is not uniform throughout the MAIN subregions.
Specifically, import transfer capabilities are:
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. o adequate in EMO fer all three sc2narios; '
' adequate in WUMS for Scenario I, but only marginally adequate for -
Scenarios 2 and 3;
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marginally adecluate in SCIL for Scenarios 1 and 2, but inadequate for Scenario 3; anc f
adequate in NI for Scenario 1, but inadequate for Scenarios 2 and 3.
Operational Readiness .
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MAIN has made extensive preparations for 1997 summer operating conditions, {
including:- significant additions of reactive support (NI and WUMS Subregions '
are adding about 3,000 MVARs), replacement of transformers, accelerated transmission line inspection and maintenance, rights-of-way maintenance (including tree trimming), and additional relay testing.
Utilities in the NI Subregion have analyzed voltage stability for a variety of contingency conditions and found that the voltage stability margin criteria will be met. Additionally, the MAIN Coordination Center is upgrading its system security analysis capability and is preparing to run daily voltage stability analyses. Generation and transmission outages are being coordinated
-within MAIN and with utilities in adjoining Regions. Additional emergency operating procedures are being developed and system operators will be trained on the new procedures. System operators are also reviewing system restoration procedures. MAIN is planning for increased communications among its members and control areas.
Overall Assessment Despite the extensive preparations and planning by MAIN and its members, the combination of generator unavailability and limited transmission capability l coupled with unanticipated circumstances such as extreme weather conditions !
could result in electricity supply shortages. If the nuclear generation is not returned to service as scheduled,- above-average temperatures occur, or l
other unanticipated equipment problem arise, utilities in portions of the NAIN Region'will' have to take such actions as public appeals, voltage reductions, and exercise interruptible demand agreements to reduce overall customer demands. They may have to curtail supply to firm customers (load shedding or i l rotating blackouts).to maintain the overall integrity of the interconnected i electric. network. i l 1 REC 0lWlENDATIONS i
( In view of the sensitive situation in the MAIN Region and the high potential !
l 'for voltage perturbations in the electric. grid that may lead to the l
- i. loss-of-offsite power to nuclear power plants, EELB suggests that the ;
j NRR Division of Reactor Projects III and IV and/or the Region III should ;
l communicate with the' licensees of nuclear power plants operating in the MAIN j Region to inform them that discretionary emergency diesel generator !
maintenance should not be scheduled for June through late September 1997. !
( l
This action would help to maxialze the number of emergency power sources available in the event of a loss-of-offsite power.
The Division of Reactor Projects III and IV and/or the Region III should also j- communicate with the licensees to request that operators of nuclear power
\' plants should place special emphasis on refreshing their knowledge of procedures related to response to loss-of-offsite power to the plant. In addition, the plant should closely communicate with the corresponding MAIN l Region control area to be aware of particularly critical situations as they i occur.
ZEFERENCE North Amer.ican Electric Reliability Council - 1997 Summer Assessment, Reliability of Bulk Electricity Supply in North America l
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t Scenario 1 - 4,606 MW Total Inoperable Capacity South Wimmsin-Eastern Northern Central Upper MAIN hourt Blinois Blinois Michigan
, Jan Available Resources (MW) 47,206 8,419 18,772 9,497 10,518 Net internal Demand (MW) 40,496 6,739 17,238 7,778 8,741 Avallable Margin (%) 14.2 20.0 8.2 18.1 16.9 July Available Resources (MW) 50,339 8,862 19,441 9,959 12,077 Net Internal Demand (MW) 44,533 7,694 18,928 -
8,516 9,395 Available Margin (%) 11.5 13.2 2.6 14.5 22.2 August Available Resources (MW) 50,339 8,845 19,441 9,956 12,137 Net Internal Demand (MW) 44,189 7,421 18,928 8,286 9,554 Available Margin (%) 12.2 16.1 2.6 16.8 21.3 September Available Resources (MW) 50,818 3,712 20,556 9,820 11,730 Net Internal Demand (MW) 38,282 6,141 15,308 7,663 8,670 Available Margin (%) 24.7 29.5 23.1 22.0 26.1 1
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ATTACMENT 3
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scenario 2 - 6,125 MW Total Wble Capadty
. South Wisenesin-Bastara Northern Cameral Upper MADi nGussert Mainees Iniasis Michigan June -
Available R: :+-e (MW) 45,660 8,419 18,745 8,471 10,025 Net laternal Demand (MW) 40,496 6,739 17,238 7,778 8,741 Avallsbie :.:-sin (%) 11.3 20.0 8.0 8.2 12.8 Jah Available Resources (MW) 48,820 8,862 19,441 8,933 11,584 Net laternal Demand (MW) 44,533 7,694 18,928 8,516 9,395 Available Mart in (%) 8.6 13.2 2.6 4.7 18.9 August Available Resources (MW) 48,860 8,845 19,441 8,930 11,644 Net Internal Demand (MW) 44.189 7,421 18,928 8,286 9,554 Available Marsin (%) 9.6 16.1 2.6
- 7.2 18.0 Opember Available Resources (MW) 49,299 8,712 20,556 8,794 11,237 Net laterna1 Demand (MW) 38,282 6,141 15,808 7,663
' 8,670 Available Martin (%) 22.4 29.5 23.1 12.9 u
22.8 t
ATTAQ#ENT 4
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Scenado 3 - 7.179 MW Total Inoperable Capacity' South Wisemasin-samars Northern Cened MAIN hanourt U- *
- Bunois M aois nachigan June Available Resources (MW) 44,606 4,419 18,745 8,378 9,064 Net latemal Demand (MW) 40,496 6,739 17,238 7,778 Avallable Margin (%) 8,741 9.2 20.0 8.0 l ,34 7.2 3.6 Available P :_ e(MW) 47,766 4,862 19,441 3,840 10,623 Net latema! Demand (MW) 44,533 7,694 18,928 8,516 Available Margin (%) 9,3 95 6.6 13.2 2.6 3.7
-A - _-- - 11.6 Avallable R4Enes(MW) 47,806 4,845 19,441 ,
8,817 10,683 Net InternalDemand (MW) 44,189 7,421 18,928 Avallable Margin (%) 8,286 9,554 7.6 16.1 s.,ie.be, 2.6 6.2 10.6 Avallable Resources (MW) 44,245 4,712 20,556 8,701 '
[ 10,276 Netlatemal Demand (MW) 38,282 6,141
- 1 Avellable Margin (%) 15.808 7,663 8,670 20.7 29.5
, 23.1 11.9 15.6 9
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ATTAC M ENT 5 .
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