Demand for electricity continues to grow and the existing transmission grid across the West is aging and increasingly operating at its full capacity during peak periods of customer electric use. In order to meet future energy needs of their customers, Idaho Power and Rocky Mountain Power are working together to ensure adequate supply and enhance reliability of electric service with the Gateway West Transmission Line Project.

This project is jointly proposed by Idaho Power and Rocky Mountain Power to build and operate approximately 1,150 miles of new high-voltage transmission lines between the Windstar Substation near Glenrock, Wyoming and the Hemingway Substation near Melba, Idaho. The project would include approximately 300 miles of 230 kilovolt (kV) lines in Wyoming and approximately 850 miles of 500 kV lines in Wyoming and Idaho. This project will help supply energy to customers and improve electric system reliability by enabling delivery of electricity from existing and new generating resources, including renewable resources such as wind.

Idaho Power and Rocky Mountain Power are working with the Bureau of Land Management (BLM) as it conducts the environmental review and analysis. Our current schedule estimates line segments will be completed in phases between 2014 and 2018. We continue to work with landowners along the corridor to minimize effects as we route and design the lines.

Under many conditions, the existing high-voltage transmission lines in the West are already at full capacity. Residential customers are using more electricity now than they have in the past. In Idaho Power’s service area in the summer of 2007, there were 14 days when energy use was at capacity, where a transmission line outage would have forced Idaho Power to implement rotating customer outages. The added capacity of the Gateway West Transmission Line Project will alleviate this situation.