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September 2012  PDF | previous editions
Release Date: September 27, 2012

Table 8.12a Electric Noncoincident Peak Load and Capacity Margin: Summer Peak Period, 1986-2011 (Megawatts, Except as Noted)
Table 8.12a  Electric Noncoincident Peak Load and Capacity Margin:  Summer Peak Period, 1986-2011
                         (Megawatts, Except as Noted)






Year
Noncoincident Peak Load 1 by North American Electric Reliability Corporation (NERC) 2 Regional Assessment Area 



Capacity
Margin 21
(percent)
Eastern Interconnection

ERCOT 4
Western
Inter-
connection
All
Inter-
connections


FRCC 5


NPCC 6
Balance of Eastern Region 3
ECAR 7,8 MAAC 8,9 MAIN 8,10 MAPP 11 MISO 12 MRO 13 PJM 14 RFC 8,15 SERC 16 SPP 17 Subtotal TRE 18 WECC 19 Total 20
1986 - - 39,026 69,606 37,564 35,943 - - - - 21,029 - - - - 105,570 47,123 316,835 39,335 81,787 476,983 NA
1987 - - 42,651 72,561 40,526 37,446 - - - - 23,162 - - - - 109,798 47,723 331,216 39,339 82,967 496,173 NA
1988 - - 45,245 79,149 43,110 41,139 - - - - 24,899 - - - - 115,168 49,356 352,821 40,843 90,551 529,460 NA
1989 - - 45,031 75,442 41,614 39,460 - - - - 24,336 - - - - 117,729 49,439 348,020 40,402 90,657 524,110 NA
1990 - - 44,116 79,258 42,613 40,740 - - - - 24,994 - - - - 121,943 52,541 362,089 42,737 97,389 546,331 21.6
1991 - - 46,594 81,224 45,937 41,598 - - - - 25,498 - - - - 124,716 51,885 370,858 41,870 92,096 551,418 20.9
1992 - - 43,658 78,550 43,658 38,819 - - - - 22,638 - - - - 128,236 51,324 363,225 42,619 99,205 548,707 20.5
1993 - - 46,706 80,930 46,494 41,956 - - - - 24,396 - - - - 135,704 57,106 386,586 44,255 97,809 575,356 19.9
1994 - - 47,581 87,165 46,019 42,562 - - - - 27,000 - - - - 132,584 56,035 391,365 44,162 102,212 585,320 18.7
1995 - - 47,705 92,619 48,577 45,782 - - - - 29,192 - - - - 146,569 59,595 422,334 46,618 103,592 620,249 18.9
1996 - - 45,094 90,798 44,302 46,402 - - - - 28,253 - - - - 145,650 60,072 415,477 47,480 108,739 616,790 17.5
1997 35,375 49,269 93,492 49,464 45,887 - - - - 29,787 - - - - 137,382 36,479 392,491 50,541 110,001 637,677 16.2
1998 38,730 49,566 93,784 48,445 47,509 - - - - 30,722 - - - - 143,226 37,724 401,410 54,666 115,921 660,293 14.3
1999 37,493 52,855 99,239 51,645 51,535 - - - - 31,903 - - - - 149,685 38,609 422,616 55,529 113,629 682,122 14.6
2000 37,194 50,057 92,033 49,477 52,552 - - - - 28,605 - - - - 156,088 40,199 418,954 57,606 114,602 678,413 15.7
2001 39,062 55,949 100,235 54,015 56,344 - - - - 28,321 - - - - 149,293 40,273 428,481 55,201 109,119 687,812 14.5
2002 40,696 56,012 102,996 55,569 56,396 - - - - 29,119 - - - - 158,767 39,688 442,535 56,248 119,074 714,565 16.4
2003 40,475 55,018 98,487 53,566 56,988 - - - - 28,831 - - - - 153,110 40,367 431,349 59,996 122,537 709,375 18.6
2004 42,383 52,549 95,300 52,049 53,439 - - - - 29,351 - - - - 157,615 40,106 427,860 58,531 123,136 704,459 20.9
2005 46,396 58,960 - - - - - - - - - - 39,918 - - 190,200 190,705 41,727 462,550 60,210 130,760 758,876 15.4
2006 45,751 63,241 - - - - - - - - - - 42,194 - - 191,920 199,052 42,882 476,048 62,339 142,096 789,475 12.9
2007 46,676 58,314 - - - - - - - - - - 41,684 - - 181,700 209,109 43,167 475,660 62,188 139,389 782,227 16.1
2008 44,836 58,543 - - - - - - - - - - 39,677 - - 169,155 199,779 43,476 452,087 62,174 134,829 752,470 18.2
2009 46,550 55,944 - - - - - - - - - - 37,963 - - 161,241 191,032 41,465 431,701 63,518 128,245 725,958 22.2
2010 R 45,722 R 60,554 - - - - - - 4,598 108,346 R - - 136,465 R - - R 164,058 R 53,077 466,543 R 65,776 R 129,352 R 767,948 R 19.1
2011F 46,091 60,262 - - - - - - 4,810 98,068 - - 148,941 - - 164,510 53,084 469,412 63,770 130,962 770,497 22.2
1Noncoincident peak load is the sum of two or more peak loads on individual systems that do not occur
at the same time interval.  Peak load represents one hour of a day during the associated peak period.  See
"Noncoincident Peak Load" in Glossary.
14PJM Interconnection (PJM).
2See "North American Electric Reliablility Corporation (NERC)" in Glossary.  Data include the U.S.
portion of NERC only.
15ReliabilityFirst Corporation (RFC).
3Historically, the MRO, RFC, SERC, and SPP regional boundaries were altered as utilities changed
reliability organizations.  The historical data series for these regions have not been adjusted.  Instead, the
"Balance of Eastern Region" category was introduced to provide a consistent trend of the Eastern
Interconnection.
16SERC Reliability Corporation (SERC).
4Electric Reliability Council of Texas (ERCOT). 17Southwest Power Pool (SPP).
5Florida Reliability Coordinating Council (FRCC). 18Texas Reliability Entity (TRE).
6Northeast Power Coordinating Council (NPCC). 19Western Electricity Coordinating Council (WECC).
7East Central Area Reliability Coordination Agreement (ECAR). 20United States excluding Alaska and Hawaii.
8ECAR, MAAC, and MAIN dissolved at the end of 2005.  Many of the former utility members joined
RFC, which came into existence on January 1, 2006.  RFC submitted a consolidated filing covering the
historical NERC regions of ECAR, MAAC, and MAIN.
21Capacity margin is the amount of unused available capability of an electric power system at peak load
as a percentage of capacity resources.  Data are for the United States excluding Alaska and Hawaii.
9Mid-Atlantic Area Council (MAAC). R=Revised.  F=Forecast.  NA=Not available.  - - =Not applicable.  
10Mid-America Interconnected Network (MAIN). Notes:  -  The summer peak period is June through September.  -  Totals may not equal sum of
components due to independent rounding.
11Mid-Continent Area Power Pool (MAPP). Web Page:  For related information, see http://www.eia.gov/electricity/.
12Midwest Independent Transmission System Operator (MISO). Sources:  U.S. Energy Information Administration (EIA), Electric Power Annual 2010 (November 2011),
Tables 4.1.A., 4.1.B., 4.3.A., and 4.3.B.; and EIA, Form EIA-411, "Coordinated Bulk Power Supply and
Demand Program Report," and predecessor forms. 
13Midwest Reliability Organization (MRO).  
U.S. Energy Information Administration (EIA)