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Independent review of the IESO's Dispatch Scheduling and Optimization, and Day-Ahead Calculation Engine

September 13, 2018

A 2018 review of the IESO's Dispatch Scheduling and Optimization (DSO), and Day-Ahead Calculation Engine (DACE) processes and procedures was completed without qualifications. During the review period, nothing material came to the attention of the audit firm, PricewaterhouseCoopers (PWC), which would indicate that the dispatch algorithms were not operating in accordance with the relevant market rules. The full reports are available at DACE Review and DSO Review.

The review included an examination of both the DACE and DSO tools. The DACE tool is the software program that runs the day-ahead dispatch algorithm and is used to optimize day-ahead schedules over a 24-hour period for energy and operating reserves. The DSO tool is the software program that implements the dispatch algorithms, calculates market clearing prices and formulates dispatch instructions for generators and loads. The DSO tool finds an optimal outcome every five minutes by integrating market and reliability priorities, which is crucial to serving all Ontario electricity consumers.

The PWC review approach was extensive and included, but was not limited to:

  • Understanding applicable market rules and related processes and procedures

  • Control Room observation

  • Development and execution of automated screening tests

  • Base case and save case testing

  • Comparison of DSO tool input/output data to DSO save case and IESO website

This is the seventh independent review of the DSO since the market opened in Ontario and the second review of DACE.


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