Summer reserve margins predicted to be adequate in most regions; ERCOT below reserve capacity targets

Most of North America has sufficient resources available to meet summer peak demands, the North American Electric Reliability Corporation’s (NERC) 2012 Summer Reliability Assessment finds.

However, planning reserve margins in the Electric Reliability Council of Texas (ERCOT) assessment area are projected to be below the NERC Reference Margin Level, the threshold by which resource adequacy is measured. In California, reserves are projected to be tight, but manageable, through the summer months.

“Reduced planning reserves in certain areas will challenge operations this summer,” said Mark Lauby, vice president and director of Reliability Assessment and Performance Analysis. “NERC has reviewed the operating procedures and preparations in the assessment areas, and in most areas they appear to be sufficient to meet these challenges.”

Since summer 2011, capacity resources have grown across North America by approximately 12,310 megawatts, most notably within the SERC Reliability Corporation and the Northeast Power Coordinating Council areas. Compared to the 2011 projections, NERC-wide total peak demand forecast is 3,700 MW lower. The largest increase in peak demand is expected in ERCOT, where a 1.7 percent increase is projected.

“With continued growth in peak demand and only a small amount of new generation coming online, resource adequacy levels in ERCOT have fallen below targets,” said John Moura, manager of Reliability Assessment at NERC. “If ERCOT experiences stressed system conditions or record-breaking electricity demand due to extreme and prolonged high temperatures, system operators will most likely rely on demand response and emergency operating procedures, which may include initiating rotating outages to maintain the reliability of the interconnection.”

Key highlights for summer 2012:

  • Extreme weather could lead to stress conditions in Southern California and Texas; planned interruptions of firm load may be necessary
  • The unanticipated outage of San Onofre Nuclear Generating Station reduces available summer capacity; transmission ties critical to the reliability of Southern California
  • Enhanced operations and planning approaches instituted in response to 2011 Southwest outage
  • Variable generation continues to increase in most assessment areas
  • Demand-side management key to maintaining reliability this summer
  • Extreme weather events will challenge bulk power system operators
  • Lower global liquefied natural gas supply may impact generation in New England; ISO to implement proactive measures.