The Role of Out-of-Market Corrections in Day-Ahead Scheduling

In order to ensure a reliable and continuous supply of electric energy, operators must manage hundreds to thousands of generators with complex operating requirements, maintain synchronism, and manage thousands of transmission assets. Further complications arise due to stringent reliability standards, resource uncertainty, and limited economical energy storage. With advances in algorithmic performance and hardware, such optimization problems still require an engineered and simplified market structure. Market operators must therefore adjust the proposed market solution in order to obtain a valid solution. An overview of existing industry practices related to such market adjustments, referred to as out-of-market corrections, is presented. This paper also analyzes the market implications and required out-of-market corrections for the day-ahead scheduling process. Multiple out-of-market correction algorithms are created and used to analyze the potential impacts on market solutions and settlements. Finally, such solutions are compared against an extensive form stochastic unit commitment solution.