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Generation Reserves: The Grid Security Question

A cost-benefit study shows the value of adding synchronized generating reserves to prevent blackouts on the scale of Aug.14.
Fortnightly Magazine - January 2004
  1. to meet all the constraints and fulfill the security requirements as specified by contingencies. UPLAN also models remedial action schemes to mitigate contingencies by taking appropriate remedial actions specified by ISOs and RTOs. UPLAN-NPM uses an Optimal AC/DC Power Flow algorithm with an embedded full-fledged contingency analysis package for real-time generator dispatch to manage congestion and determine LMP. The real-time dispatch algorithm is compatible with the programs used by most of the ISO/RTOs in the United States.
    In UPLAN-NPM, a multi-area, multi-commodity Nash equilibrium algorithm simulates the day-ahead market and determines the forward electricity prices as well as ancillary service prices such as regulation, spinning, reserve, and capacity prices.
  2. As reported by the International Transmission Co., Aug. 17, 2003,
  3. Anne D'Innocenzio, , Wednesday, Aug. 28, 2003, estimates the cost of Aug. 14, 2003, outage to be more than $4 billion.

Generation For Reliability: Seven Recommendations

  • Optimize the operating reserve, using more flexible generators with quick response.
  • Increase the synchronized (on line) operating reserves.
  • Select on line reserve units, taking into consideration location, response time, and frequency of loop flow in the system.
  • Improve interregional coordination among different control areas so as to determine the quality, quantity, and strategic location of the reserves
  • Encourage investment in transmission.
  • Conduct integrated generation-transmission studies on a regular basis across the entire grid for a large number of contingency scenarios, using a model that realistically represents the system, such as UPLAN, over a period of time, over the operating horizon of the system.
  • Reduce the cost of improving reliability by conducting integrated generation-transmission optimization over the planning horizon of the system.


Security Constrained Unit Commitment (SCUC): The commitment of sufficient amount of generation resources to meet sufficient demand while meeting all transmission constraints, reserve requirements, and generator operating constraints.

Synchronized Operating Reserve: Operating reserves provided by synchronized resources such as regulation or spinning reserves that can respond immediately to dispatch instructions.

Security Constrained Economic Dispatch (SCED): The determination of the generation dispatch that incorporates all transmission security constraints such as flow limits, interface limits, and contingency constraints necessary for reliability. SCED assures that the units committed by SCUC are dispatched across the entire network to minimize the total dispatch cost and provide additional security by committing out-of-schedule units to meet unforeseen requirements at the dispatch time.

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