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 (Gateway West).

Gateway West is a joint proposal from Idaho Power Company and Rocky Mountain Power to build and operate approximately 1,150 miles of new 230 kilovolt (kV) and 500 kV transmission lines from the planned Windstar substation near Glenrock, Wyoming to the planned Hemingway substation near Melba, 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 as it conducts the environmental review and analysis.

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.