Table 8.8.A. Summer Net Internal Demand, Capacity Resources, and Capacity Margins by North American Electric Reliability Assessment Area,
2002 - 2012, Actual
 

Net Internal Demand (Megawatts) -- Summer
  Eastern Interconnection ERCOT Western Interconnection All Interconnections
Period FRCC NPCC Balance of Eastern Region ECAR MAAC MAIN MAPP MISO MRO PJM RFC SERC SPP TRE WECC Contiguous U.S.
2002 37,951 55,164 430,396 101,251 54,296 53,267 -- -- 28,825 -- -- 154,459 38,298 55,833 117,032 696,376
2003 40,387 53,936 422,253 98,487 53,566 53,617 -- -- 28,775 -- -- 148,380 39,428 59,282 120,894 696,752
2004 42,243 51,580 419,349 95,300 52,049 50,499 -- -- 29,094 -- -- 153,024 39,383 58,531 121,205 692,908
2005 45,950 57,402 455,594 -- -- -- -- -- 38,266 -- 190,200 186,049 41,079 59,060 128,464 746,470
2006 45,345 60,879 469,639 -- -- -- -- -- 40,661 -- 190,800 196,196 41,982 61,214 139,402 776,479
2007 46,434 58,221 465,229 -- -- -- -- -- 40,249 -- 177,200 205,321 42,459 61,063 135,839 766,786
2008 44,660 59,896 447,629 -- -- -- -- -- 38,857 -- 169,155 196,711 42,906 61,049 130,916 744,151
2009 46,263 55,730 424,714 -- -- -- -- -- 35,849 -- 161,241 186,507 41,117 63,518 122,881 713,106
2010 45,522 56,232 453,436 -- -- -- 4,493 100,963 -- 135,142 -- 160,896 51,942 64,378 126,944 746,513
2011 44,798 62,313 466,360 -- -- -- 4,641 98,290 -- 146,443 -- 161,995 54,991 68,416 117,755 759,642
2012 44,338 58,319 469,273 -- -- -- 4,967 96,769 -- 156,319 -- 158,041 53,177 66,548 130,465 768,943

 

Capacity Resources (Megawatts) -- Summer
  Eastern Interconnection ERCOT Western Interconnection All Interconnections
Period FRCC NPCC Balance of Eastern Region ECAR MAAC MAIN MAPP MISO MRO PJM RFC SERC SPP TRE WECC Contiguous U.S.
2002 43,342 66,208 504,357 119,736 63,619 67,025 -- -- 34,259 -- -- 172,485 47,233 76,849 142,624 833,380
2003 46,806 70,902 513,382 123,755 65,897 67,410 -- -- 33,287 -- -- 177,231 45,802 74,764 150,277 856,131
2004 48,579 71,532 526,454 127,919 66,167 65,677 -- -- 35,830 -- -- 182,861 48,000 73,850 155,455 875,870
2005 50,200 72,258 532,917 -- -- -- -- -- 46,792 -- 220,000 219,749 46,376 66,724 160,026 882,125
2006 50,909 73,095 534,270 -- -- -- -- -- 50,116 -- 214,693 223,630 45,831 70,664 162,288 891,226
2007 53,027 73,771 543,608 -- -- -- -- -- 47,259 -- 213,544 234,232 48,573 75,912 168,080 914,397
2008 51,541 75,894 539,936 -- -- -- -- -- 48,180 -- 215,477 228,169 48,110 74,274 167,860 909,504
2009 49,239 78,639 559,823 -- -- -- -- -- 47,529 -- 215,700 247,400 49,194 76,280 152,467 916,449
2010 53,370 67,569 570,396 -- -- -- 7,210 131,691 -- 167,647 -- 200,511 63,337 73,857 158,407 923,599
2011 54,340 72,277 549,067 -- -- -- 5,244 110,611 -- 170,066 -- 201,103 62,044 69,595 147,147 892,426
2012 53,475 76,525 576,314 -- -- -- 5,981 112,085 -- 187,305 -- 198,140 72,802 73,219 147,527 927,060

 

Capacity Margin (Percent) -- Summer
  Eastern Interconnection ERCOT Western Interconnection All Interconnections
Period FRCC NPCC Balance of Eastern Region ECAR MAAC MAIN MAPP MISO MRO PJM RFC SERC SPP TRE WECC Contiguous U.S.
2002 12.4% 16.7% 14.7% 15.4% 14.7% 20.5% -- -- 15.9% -- -- 10.5% 18.9% 27.3% 17.9% 16.4%
2003 13.7% 23.9% 17.8% 20.4% 18.7% 20.5% -- -- 13.6% -- -- 16.3% 13.9% 20.7% 19.6% 18.6%
2004 13.0% 27.9% 20.3% 25.5% 21.3% 23.1% -- -- 18.8% -- -- 16.3% 18.0% 20.7% 22.0% 20.9%
2005 8.5% 20.6% 14.5% -- -- -- -- -- 18.2% -- 13.5% 15.3% 11.4% 11.5% 19.7% 15.4%
2006 10.9% 16.7% 12.1% -- -- -- -- -- 18.9% -- 11.1% 12.3% 8.4% 13.4% 14.1% 12.9%
2007 12.4% 21.1% 14.4% -- -- -- -- -- 14.8% -- 17.0% 12.3% 12.6% 19.6% 19.2% 16.1%
2008 13.4% 21.1% 17.1% -- -- -- -- -- 19.3% -- 21.5% 13.8% 10.8% 17.8% 22.0% 18.2%
2009 6.0% 29.1% 24.1% -- -- -- -- -- 24.6% -- 25.2% 24.6% 16.4% 16.7% 19.4% 22.2%
2010 14.7% 16.8% 20.5% -- -- -- 37.7% 23.3% -- 19.4% -- 19.8% 18.0% 12.8% 19.9% 19.2%
2011 17.6% 13.8% 15.1% -- -- -- 11.5% 11.1% -- 13.9% -- 19.4% 11.4% 1.7% 20.0% 14.9%
2012 17.1% 23.8% 18.6% -- -- -- 17.0% 13.7% -- 16.5% -- 20.2% 27.0% 9.1% 11.6% 17.1%

Notes:
NERC region and reliability assessment area maps are provided on EIA's Electricity Reliability web page: http://www.eia.gov/cneaf/electricity/page/eia411/eia411.html
Net Internal Demand represent the system demand that is planned for by the electric power industry`s reliability authority and is equal to Internal Demand less Direct Control Load Management and Interruptible Demand.
Capacity Resources: Utility and nonutility-owned generating capacity that is existing or in various stages of planning or construction, less inoperable capacity, plus planned capacity purchases from other resources, less planned capacity sales.
Capacity Margin is the amount of unused available capability of an electric power system at peak load as a percentage of capacity resources.
The Summer peak period begins on June 1 and extends through September 30.
Historically 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.
ECAR, MAAC, and MAIN dissolved at the end of 2005. Many of the former utility members joined RFC. Reliability First Corporation (RFC) came into existence on January 1, 2006. RFC submitted a consolidated filing covering the historical NERC regions of ECAR, MAAC, and MAIN.
N/A - Not Available
Source: U.S. Energy Information Administration, Form EIA-411, "Coordinated Bulk Power Supply and Demand Program Report."