Expansion and Repowering of Mammoth Geothermal Resource: Selection of Generation Cycle and Expander Technology

Abstract

In 2010, Ormat Technologies, Inc. became the sole owner of the land, power plants and associated equipment comprising the Mammoth Geothermal complex. The Mammoth complex is located near Mammoth Lakes, California and includes three binary plants, which were completed in 1985 and 1990 and have a generating capacity of approximately 29 MW. The Mammoth complex sits on a high-quality geothermal reservoir and has been identified as being capable of significantly increased production. As the sole owner of the complex, a plan to move quickly to increase well field production and expand the generating facility with a goal to significantly increase generation capacity was set in place. Additional production and injection wells were identified and developed. Based on successful experience gained in repowering and expansion of the Steamboat complex, a plan has been developed to replace the existing aging generating plants with two new higher efficiency Ormat plants. The new Ormat units will utilize multi-level binary ORC technology.