2.2.2 Fossil-Based Generation

and blades, increasing the output and useful life of about 1,000 MW of existing generating capability from the same wind source.

Due to Wyoming’s high average wind speeds, PacifiCorp has already procured more than 1,900 MW of new wind generation capacity, which will be delivered to load centers through the approved Energy Gateway transmission projects. More specifically, the Gateway South line, originating at the Aeolus Substation, will be the primary means of delivering the wind energy to the northern Utah load center. Additionally, in its 2021 cluster window, PacifiCorp received interconnection applications into or near Aeolus Substation totaling nearly 1,400 MW.

PacifiCorp’s IRP compared the costs of wind energy resources over the wide range of its multi-state service territory. The cost of wind energy from an area designated as “Medicine Bow”, the location of the Aeolus Substation into which the Project would connect, is shown as being lower in cost than wind from any other region. An additional 3,628 MW of new wind energy capacity is planned by 2040 (PacifiCorp 2021). Given this portfolio preference, the lower cost of Wyoming wind, and the number of specific wind projects in development, it is likely that a significant amount of new wind capacity will be built in the vicinity of the proposed Project.

From a transmission perspective, accommodating this additional wind capacity will be challenging, even with planned new transmission lines, such as Gateway South. This challenge is exacerbated in that wind-only transmission utilization will be inefficient. The proposed Project will increase utilization of existing and new transmission capacity in the region by shifting peak wind generation to times when transmission capacity is available which otherwise would have been curtailed due to limited transmission capacity. It will also increase grid reliability and load access for the intermittent and non-dispatchable wind resource to serve load more effectively.

PacifiCorp is anticipating nearly 3,250 MW of new, low-cost, clean energy resources by 2024 (PacifiCorp 2021). The Project is well positioned to support this increased generation growth in Wyoming and Utah.

Coal-fired steam generation provides large-scale baseload energy, serving a different function in an energy supply portfolio than pumped storage. As a major source of greenhouse gas emissions, coal-fired generation in the market region for the Project is being phased out and there are no plans for new coal-fired capacity additions. Therefore, coal is not a viable alternative to the Project.

Gas-fired power plants include simple-cycle combustion turbines (SCCT), combined-cycle combustion turbines (CCCT), and internal combustion reciprocating engines. Gas-fired generation has provided most of the peaking and intermediate capacity in the western market since the 1990s. CCCT plants are used for intermediate-to-baseload service. SCCTs, including frame turbines and aeroderivatives, are used for peaking power and have a lower capital cost than pumped storage. They, along with CCCT plants, are