JACKSON HOLE, Wyo. (AP) — A Wyoming utility company had the lowest power rates in the nation in 2017.

Lower Valley Energy, based in Afton, Wyoming, had the lowest rates for residential electricity among 813 cooperatives.

A news release says the annual ranking comes from the National Rural Utilities Cooperative Finance Corporation, which tracks industry trend.

The Bonneville Power Administration is contracting Lower Valley to build the Hooper Springs transmission line that will connect Soda Springs, Idaho, to the Lower Valley system for $65 million.

Lower Valley customers in Jackson Hole will cumulatively save about $600,000 per year for the next 40 years by financing, building and leasing the line back to Bonneville Power Administration.

Lower Valley expects to begin work in August and complete it by late fall 2019.