Overview of Southwest Colorado Power System

The power system in Southwest Colorado relies on a limited network of generation and transmission infrastructure to maintain reliability and meet member load. In 1995, Tri-State and other regional utilities recognized that the transmission system was becoming stressed and new lines needed to be built and existing lines needed to be replaced or upgraded. Tri-State studied multiple ways to address the aging infrastructure, improve reliability and meet significant new demand in the region. Among other things, the studies showed the need to rebuild the existing Nucla-Sunshine transmission line and upgrade the Montrose-Nucla-Cahone (MNC) infrastructure from 115kV to 230kV to increase capacity. In 2012, Tri-State completed the Nucla-Sunshine line.

In 2011, Tri-State formally began the process to make infrastructure improvements to MNC and upgrade the capacity from 115kV to 230kV. Tri-State continues to work through the process, which includes review by several state and federal agencies.