Renewable energy and geology in Arizona

I had the privilege of giving the keynote address to the Shlemon Specialty Conference in Tempe this morning on "Opportunities for Alternative Energy Development in Arizona and the Southwest– Geologic/Hydrologic Considerations." The event was organized by the Association of Environmental and Engineering Geologists (AEG) and the Arizona Land Subsidence Group. The technical conference drew about 110 attendees from geotechnical companies, utilities, and energy developers.

I offered an overview of the types and locations of proposed renewable energy projects or areas of potential development, along with a summary of the types of geologic hazards that occur in Arizona and surrounding states, that need to be factored in construction.

There was a strong focus in subsequent presentations during the day on subsidence and Earth fissures and their potential impacts. Ralph Weeks, with GeoSouthwest, LLC, listed 25 solar energy projects in various stages of development in Arizona, noting that 17 of them, or about 70%, are located in areas subject to subsidence and fissures. [right, solar energy potential. Credit, National Renewable Energy Lab]

Among the impacts Ralph identified as possible impacts on solar energy projects include:

• roads, power conveyances, and buried utilities
• structural foundations
• solar collectors (which have to be carefully aligned to focus their light onto the central tower)

He also talked about additional information needed to identify and characterize Earth fissures:

• basin shape and alluvium thicknesses
• timing, magnitude, and distribution of past subsidence
• mechanics of Earth fissure formation and activity
• future groundwater declines
• anthropomorphic impacts
• soft shallow soils concealing buried Earth fissures