Idaho Power has been, for several years, planning to pull out as a partner from the 3 coal power plants it has an ownership share in: North Valmy in NV, Jim Bridger in WY, and Boardman in OR [2]. Jim Bridger will have soon been due for an expensive upgrade because of environmental regulations, Boardman has seen consistent pressure from Oregon activists and regulators to bring the shutdown date closer, and North Valmy has seen less and less use because the other owner has succeeded meeting most of the Northern Nevada demand with a robust mix of natgas and solar, but also has fresh interconnects with Southern Nevada and Idaho.
In 2018, Idaho Power also joined [3] the Western Energy Imbalance Market, which streamlines realtime energy trading in the WECC interconnect. As time goes on and coal plants are retired, coal's share will decline in the energy mix, and there will be an increasing amount of quasi-'baseload' solar available to buy in the energy market. And for the times in the day when the solar generation drops off and natgas plants would often be the next sellers, Idaho Power has plenty of its own hydro it can deploy to compensate. But note that despite their well-situated position with renewables, their target for 100% renewables is still 2045 -- relatively far off.
[1] (PDF) https://oemr.idaho.gov/wp-content/uploads/3.6.18-Energy-Land... [2] http://www.spokesman.com/stories/2017/sep/16/power-company-m... [3] https://www.idahopower.com/news/idaho-power-customers-will-b...