| Title | Department of Energy DOE Low Temperature Geothermal Mineral Recovery Program |
|---|---|
| Authors | Holly THOMAS, Timothy P. REINHARDT, Brittany SEGNERI |
| Year | 2015 |
| Conference | Stanford Geothermal Workshop |
| Keywords | Geothermal, geothermal minerals, critical materials, rare earth elements, US Department of Energy, Geothermal Technology Office |
| Abstract | While geothermal power is an attractive potential source for sustainable electricity generation, the high heat temperature requirements (typically greater than 150°C) of most geothermal power systems constrain the geographic distribution and economic viability of geothermal production. At lower temperatures, the thermal conversion efficiency (converting heat to electricity) of geothermal systems is lessened, making successful developments more technically and economically challenging. The US Department of Energy Geothermal Technologies Office (GTO) has funded research to address this limitation by advancing a more non-traditional aspect of geothermal systems - strategic material or mineral recovery. By partnering with geothermal and mineral industry stakeholders to develop additional revenue streams from brines, the economic viability of geothermal projects will increase while also allowing for expanding geographic diversity of this base-load energy resource. Geothermal fluids dissolve minerals and metals from rock formations as they flow through the Earth’s subsurface. Extraction and purification of these materials recovered from geothermal brines can be viewed as “solution mining by nature.” GTO issued a Funding Opportunity Announcement (FOA) in February 2014 focused on Mineral Recovery associated with these geothermal brines. This research seeks to further the development of technologies aimed at extracting and refining these materials for beneficial purposes. GTO's objective in this FOA is to promote the advancement of thermal energy conversion processes capable of converting geothermal heat sources into power, in conjunction with the development or exploitation of technologies capable of capturing, concentrating, and/or purifying valuable materials contained within geothermal brines to economically extract resources that can provide additional revenue streams to geothermal operators. During the summer of 2014 selections for this FOA were completed and nine awards were negotiated to begin in October 2014. These nine projects cover a broad range of approaches to determine the potential mineral value-streams associated with geothermal fluids. The ongoing work will examine the feasibility of extracting rare earth or critical elements and metals using a number of different approaches, and the economic potential for the various approaches. This paper reviews the intentions behind the GTO announcement and introduces the nine projects that are now in progress and their project goals. |