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The 2020 State of the Interconnection (SOTI) is a summary of the past year’s performance and review of trends in the Western Interconnection. The SOTI gathers data from a variety of sources to provide a comprehensive summary of information on the reliability and security of the bulk power system (BPS). 

-How to Use This Report 

The SOTI is a reference tool divided into sections that you can access using the navigation bar on the left. Each section is divided into pages that focus on a specific topic.  


-Interacting with Charts and Maps 

Many pages feature interactive charts that allow you to explore the data presented. In many cases, you can apply custom filters or delve into certain data sets for more detail. Most maps are interactive, with some allowing you to zoom in and out and switch between different layers. 


-Trend Analysis

Where appropriate, the SOTI includes a statistical test of recent trends based on the selections of the user, typically over the last five years.  Trends that are significant at the 0.05 level are indicated. Significance at the 0.05 level means that if there were no trends, the likelihood of seeing results as extreme as those observed would be only 5%. A paper on how the significant trends were calculated can be found here: Statistical Analysis Appendix.docx.