Play Fairways Geothermal Resource Analysis, Washington

Results of the resource potential model developed by Boschmann and others, 2014, showing the three target areas, Mount Baker, Mount Saint Helens, and the Wind River Valley.

AltaRock Energy, in cooperation with the Washington Division of Geology and Earth Resources (WADGER), is conducting a detailed exploration study of Washington State as part of the Play Fairway grant funded by the DOE Geothermal Technologies office. WADGER recently created a Washington State geothermal resource potential model that incorporates numerous variables to assess heat and permeability using existing data and data developed for the National Geothermal Data System, which was used to select three promising plays along the central axis of the Cascade Range central magmatic arc: Wind River Valley, Mount Saint Helens and Mount Baker.

In the Pacific Northwest region of the U.S., geothermal resources of the Cascades Range are largely undeveloped. The challenge of finding and developing geothermal resources in the Cascades is related to the complexity of crustal deformation in this region, as well as dense vegetation, glacial veneers, and extreme precipitation that erodes heat at very shallow depths. Therefore, as part of Phase I of the Play Fairway project, AltaRock Energy has developed an innovative geothermal exploration technique that specifically models crustal deformation in this region, and how it produces favorable geothermal resources. The results of Phase I provided the basis for an exploration plan at the three plays that is focused, cost-effective, and low-risk.

Phase II field activities will include high-resolution ground-based geophysical surveys within areas of interest at the three plays to be incorporated into favorability and risk models developed during Phase II. During Phase II, work will focus on clear drilling targets within developable geothermal lease areas and lead to a Go/No Go decision based on levelized cost of energy studies for each area. Phase III will include drilling for geothermal resources at sites identified and studied during Phase II.

Successful completion of the project will be a large step toward advancing geothermal energy development in Washington State, a task that AltaRock Energy is well-positioned to lead. AltaRock has strong relationships with Snohomish County Public Utility District, Weyerhaeuser who holds geothermal leases at Mount St Helens, and CYRQ Energy, a geothermal company with leaseholds at Mount Baker. In addition to the exploration advances made at the three plays themselves, the methodology developed over the course of this work will be applicable to similar play-types in the Cascades of the Pacific Northwest in three states.