Table 8.9.A. Winter Net Internal Demand, Capacity Resources, and Capacity Margins by North American Electric Reliability Assessment Area,
2002 - 2012, Actual
 

Net Internal Demand (Megawatts) -- Winter
  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 / 2003 42,001 45,980 360,748 84,844 46,159 39,974 -- -- 23,090 -- -- 137,541 29,140 44,719 94,554 588,002
2003 / 2004 36,229 47,850 357,026 86,332 45,625 39,955 -- -- 24,042 -- -- 133,244 27,828 41,988 100,337 583,430
2004 / 2005 41,449 47,859 371,011 91,800 45,565 40,618 -- -- 24,446 -- -- 139,486 29,096 44,010 101,002 605,331
2005 / 2006 42,493 46,328 375,365 -- -- -- -- -- 32,854 -- 151,600 160,054 30,857 46,991 105,670 616,847
2006 / 2007 45,993 48,394 385,887 -- -- -- -- -- 34,582 -- 147,800 173,036 30,469 46,038 107,586 633,898
2007 / 2008 46,093 46,185 383,779 -- -- -- -- -- 34,358 -- 141,200 176,766 31,455 46,068 113,504 635,629
2008 / 2009 45,042 47,151 384,495 -- -- -- -- -- 34,539 -- 142,395 175,199 32,362 46,747 110,977 634,412
2009 / 2010 51,703 44,864 399,204 -- -- -- -- -- 33,983 -- 143,827 188,653 32,741 56,191 106,256 658,219
2010 / 2011 45,954 44,172 389,351 -- -- -- 4,877 80,311 -- 115,535 -- 148,062 40,566 55,917 99,515 634,909
2011 / 2012 39,924 43,806 385,428 -- -- -- 4,443 83,946 -- 110,963 -- 147,454 38,622 50,100 107,568 626,826
2012 / 2013 36,409 45,545 386,359 -- -- -- 4,925 74,430 -- 122,566 -- 149,359 35,079 46,909 101,706 616,927

 

Capacity Resources (Megawatts) -- Winter
  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 / 2003 46,219 68,884 511,642 123,823 66,143 66,694 -- -- 33,224 -- -- 174,925 46,833 73,335 132,278 832,358
2003 / 2004 50,010 73,123 524,995 129,351 68,134 68,942 -- -- 32,769 -- -- 179,810 45,989 77,111 152,158 877,397
2004 / 2005 51,196 74,277 538,041 131,187 69,604 66,414 -- -- 34,371 -- -- 186,784 49,681 71,902 149,360 884,776
2005 / 2006 49,066 76,076 545,850 -- -- -- -- -- 44,620 -- 229,000 224,652 47,578 61,003 152,211 884,206
2006 / 2007 56,896 76,110 547,005 -- -- -- -- -- 46,959 -- 220,930 231,917 47,199 71,451 166,362 917,824
2007 / 2008 57,510 75,772 537,094 -- -- -- -- -- 44,987 -- 212,257 229,627 50,223 75,504 167,770 913,650
2008 / 2009 53,278 79,394 545,843 -- -- -- -- -- 47,343 -- 215,477 234,797 48,226 73,910 167,312 919,736
2009 / 2010 52,751 78,992 567,746 -- -- -- -- -- 46,422 -- 215,700 255,527 50,097 69,490 151,022 920,002
2010 / 2011 57,358 70,557 573,274 -- -- -- 6,941 129,241 -- 167,647 -- 207,558 61,888 77,660 156,413 935,262
2011 / 2012 56,466 72,741 544,706 -- -- -- 4,960 98,329 -- 170,077 -- 212,063 59,276 69,202 150,091 893,206
2012 / 2013 57,431 79,173 576,569 -- -- -- 6,220 110,600 -- 184,185 -- 205,376 70,188 74,107 154,380 941,660

 

Capacity Margin (Percent) -- Winter
  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 / 2003 9.1% 33.3% 29.5% 31.5% 30.2% 40.1% -- -- 30.5% -- -- 21.4% 37.8% 39.0% 28.5% 29.4%
2003 / 2004 27.6% 34.6% 32.0% 33.3% 33.0% 42.0% -- -- 26.6% -- -- 25.9% 39.5% 45.5% 34.1% 33.5%
2004 / 2005 19.0% 35.6% 31.0% 30.0% 34.5% 38.8% -- -- 28.9% -- -- 25.3% 41.4% 38.8% 32.4% 31.6%
2005 / 2006 13.4% 39.1% 31.2% -- -- -- -- -- 26.4% -- 33.8% 28.8% 35.1% 23.0% 30.6% 30.2%
2006 / 2007 19.2% 36.4% 29.5% -- -- -- -- -- 26.4% -- 33.1% 25.4% 35.4% 35.6% 35.3% 30.9%
2007 / 2008 19.9% 39.0% 28.5% -- -- -- -- -- 23.6% -- 33.5% 23.0% 37.4% 39.0% 32.3% 30.4%
2008 / 2009 15.5% 40.6% 29.6% -- -- -- -- -- 27.0% -- 33.9% 25.4% 32.9% 36.8% 33.7% 31.0%
2009 / 2010 2.0% 43.2% 29.7% -- -- -- -- -- 26.8% -- 33.3% 26.2% 34.6% 19.1% 29.6% 28.5%
2010 / 2011 19.9% 37.4% 32.1% -- -- -- 29.7% 37.9% -- 31.1% -- 28.7% 34.5% 28.0% 36.4% 32.1%
2011 / 2012 29.3% 39.8% 29.2% -- -- -- 10.4% 14.6% -- 34.8% -- 30.5% 34.8% 27.6% 28.3% 29.8%
2012 / 2013 36.6% 42.5% 33.0% -- -- -- 20.8% 32.7% -- 33.5% -- 27.3% 50.0% 36.7% 34.1% 34.5%

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 Winter peak period begins October 1 and extends through May 31.
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."