Advanced Materials Enable Renewable Geothermal Energy Capture and Generation

Abstract

Geothermal power is a promising renewable energy source able to provide naturally a continuous baseload power. Original exploitation of this technology limited to locations where geothermal heat is easily accessible, such as naturally occurring hot springs, steam vents, or hot fluids at shallow depths. Engineered geothermal systems (EGS) have been developed, which involves deep drilling to exploit the heat from impermeable hot rocks, and could contribute to make geothermal sources more widespread available. To make these incentives also economically viable, innovative materials solutions and an improved understanding of the long-term interaction between the materials and their harsh environment is of key importance. An important contribution comes by researching hard materials for drill bits to extend their lifetime in highly abrasive and corrosive environments at high temperatures and developing site-specific materials for proppants in conjunction with stimulation techniques. Improved monitoring of the downhole requires materials developments to make fiber optic cables and power electronics withstand the hostile environment they should operate in. When assessing the heat reservoir and the subsequent production phase, the accumulated deposition of material inside the pipes (scaling) and the extreme corrosion and temperature problems need to be tackled from a materials' perspective. This involves the development of corrosion resistant materials for the pipes, equipped with protective outer coatings and insulation, and inner liners. Novel polymeric, ceramic, or metallic membranes to separate and reinject gases would make the operation of a zero carbon emission plant possible. During the operation, continuous monitoring of the system should allow for early intervention thus reducing the risk of a fatal breakdown of a well too early in its exploitation life. Also the downtime due to replacement or maintenance of instrumentation such as downhole pumps could be reduced by selecting specific metal alloys. This chapter will provide a brief review on advanced materials that enable renewable geothermal energy capture and generation.