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Declaring Emergencies in California: The Realities of ISO Operation

An independent system operator's view on the energy crisis and the realities of maintaining reliability.
Fortnightly Magazine - October 15 2001

boiler tube leaks, casing problems, turbine seal leaks and turbine blade wear, as well as valve and pump motor failures. The higher outage levels are expected to continue until the much-needed repairs are made. In addition, in-area facilities are exhausting their allowed operating hours or are consuming their allowed nitrogen oxide (NO x) emission credits due to unprecedented duration of operation. 9 Due to the need for increased operation to avert rolling blackouts, some power plants in the CAISO control area have jeopardized future operation of their facilities.

Moreover, planned outages can no longer be deferred; these units must be readied for the upcoming summer. For the example dates, total outages have ranged from 3,000 to over 15,000 MW, with forced outages during the summer well above the 2,500 MW the CAISO typically experienced.

Figure 4 provides a brief history of in-state generation capacity (MW) that was curtailed (including planned and unplanned outages) for various reasons in year 2000 and the beginning of 2001.

While there has been considerable effort to reduce the number of outages, significant capacity that has been returned to service resides in the southern part of California and is not always available, due to congestion, to alleviate conditions in Northern California. To that end, there is and will continue to be for the foreseeable future a large amount of California generation unavailable due to outages.

Avoiding Blackouts:
Changes California should Consider

  • Greater coordination of generator outages across California and the West,
  • Improved market design which adheres to the engineering principles and laws of physics,
  • Increased coordination between state and federal regulators and their perspective roles,
  • Clearly defined roles and responsibilities for the CAISO: obligation to serve and resource/transmission planning,
  • Established demand response programs,
  • Streamlined environmental policies,
  • Firm rules to resolve market power, and
  • Well-practiced conservation and use of renewable energy sources.


Special thanks to Kevin Graves and Clyde Loutan, Kristen Kelley, Eddie Dehdashti and many others at the CAISO for their valuable contributions.

Given the limitations previously addressed, the actual generation capacity available to the CAISO to meet system demand is well below the values reported to the media by the WSCC, observers and industry professionals who base their calculations on the system nameplate generation capacity. Using nameplate ratings and assumptions about planned and unplanned outages leads to erroneous conclusions that a surplus of capacity exists in California, and thereby only hinders the efforts of all involved to effectively deal with California's energy crisis.

Furthermore, there are a few other components that actually assist in meeting CAISO system load. These include net interchange volume (imports), dynamics, demand reduction programs, and UDC Interruptible load and firm load curtailments. But before we introduce the other generation resource components, it is important to understand the information regarding other resources the system operators rely on in analyzing emergency situations. System operators estimate additional resource capacity (other than internal generation resources) by the volume of pre-scheduled imports into the control area.

Disappearing Imports: Being Forced To Go It Alone

The pre-scheduled net interchange represents imports that have been scheduled through the