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

Table 8.12b Electric Noncoincident Peak Load and Capacity Margin: Winter Peak Period, 1986-2011 (Megawatts, Except as Noted)
Table 8.12b  Electric Noncoincident Peak Load and Capacity Margin:  Winter 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 - - 37,976 64,561 32,807 28,036 - - - - 18,850 - - - - 101,849 33,877 279,980 28,730 76,171 422,857 NA
1987 - - 41,902 68,118 35,775 30,606 - - - - 19,335 - - - - 105,476 34,472 293,782 31,399 81,182 448,265 NA
1988 - - 42,951 67,771 36,363 30,631 - - - - 20,162 - - - - 108,649 35,649 299,225 34,621 82,937 459,734 NA
1989 - - 42,588 73,080 38,161 33,770 - - - - 21,360 - - - - 121,995 42,268 330,634 38,388 84,768 496,378 NA
1990 - - 40,545 67,097 36,551 32,461 - - - - 21,113 - - - - 117,448 38,949 313,619 35,815 94,252 484,231 NA
1991 - - 41,866 71,181 37,983 33,420 - - - - 21,432 - - - - 119,575 38,759 322,350 35,448 86,097 485,761 NA
1992 - - 41,125 72,885 37,915 31,289 - - - - 21,866 - - - - 121,250 39,912 325,117 35,055 91,686 492,983 NA
1993 - - 42,063 81,846 41,406 34,966 - - - - 21,955 - - - - 133,635 41,644 355,452 35,407 88,811 521,733 NA
1994 - - 42,547 75,638 40,653 33,999 - - - - 23,033 - - - - 132,661 42,505 348,489 36,180 91,037 518,253 NA
1995 - - 42,755 83,465 40,790 35,734 - - - - 23,429 - - - - 142,032 44,624 370,074 36,965 94,890 544,684 NA
1996 - - 41,208 84,534 40,468 37,162 - - - - 24,251 - - - - 143,060 49,095 378,570 38,868 95,435 554,081 27.7
1997 33,076 41,338 75,670 37,217 34,973 - - - - 25,390 - - - - 122,649 27,437 323,336 37,966 94,158 529,874 26.0
1998 39,975 44,199 84,401 36,532 37,410 - - - - 26,080 - - - - 127,416 27,847 339,686 41,876 101,822 567,558 25.7
1999 40,178 45,227 86,239 40,220 39,081 - - - - 25,200 - - - - 128,563 27,963 347,266 39,164 99,080 570,915 26.7
2000 38,606 43,852 84,546 43,256 41,943 - - - - 24,536 - - - - 139,146 30,576 364,003 44,641 97,324 588,426 29.5
2001 40,922 42,670 85,485 39,458 40,529 - - - - 21,815 - - - - 135,182 29,614 352,083 44,015 96,622 576,312 28.9
2002 45,635 46,009 87,300 46,551 42,412 - - - - 23,645 - - - - 141,882 30,187 371,977 45,414 95,951 604,986 29.4
2003 36,841 48,079 86,332 45,625 41,719 - - - - 24,134 - - - - 137,972 28,450 364,232 42,702 102,020 593,874 33.5
2004 44,839 48,176 91,800 45,905 42,929 - - - - 24,526 - - - - 144,337 29,490 378,987 44,010 102,689 618,701 31.6
2005 42,657 46,828 - - - - - - - - - - 33,748 - - 151,600 164,638 31,260 381,246 48,141 107,493 626,365 30.2
2006 42,526 46,697 - - - - - - - - - - 34,677 - - 149,631 175,163 30,792 390,263 50,402 111,093 640,981 30.9
2007 41,701 46,795 - - - - - - - - - - 33,191 - - 141,900 179,888 31,322 386,301 50,408 112,700 637,905 30.4
2008 45,275 46,043 - - - - - - - - - - 36,029 - - 142,395 179,596 32,809 390,829 47,806 113,605 643,557 31.0
2009 53,022 44,864 - - - - - - - - - - 35,351 - - 143,827 193,135 32,863 405,176 56,191 109,565 668,818 28.5
2010 R 46,135 R 45,712 - - - - - - 5,069 86,728 R - - 115,535 R - - R 152,030 R 41,226 400,589 R 57,315 R 101,668 R 651,418 R 33.7
2011F 47,613 46,788 - - - - - - 5,118 79,052 - - 130,711 - - 154,150 41,138 410,168 51,642 106,717 662,928 33.1
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 winter peak period is October through May of the following year.  In this table, data years
correspond to the beginning of the winter peak period; for example, data year 2011 represents October
2011-May 2012.  -  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., 4.4.A., and 4.4.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)