High-Potential Working Fluids for Next Generation Binary Cycle Geothermal Power Plants Geothermal Project

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Last modified on July 22, 2011.

Project Title High-Potential Working Fluids for Next Generation Binary Cycle Geothermal Power Plants
Project Type / Topic 1 Recovery Act: Enhanced Geothermal Systems Component Research and Development/Analysis
Project Type / Topic 2 Working Fluids for Binary Power Plants
Project Description GE Global Research, in partnership with AltaRock Energy Inc., (ARE) and the National Institute of Standards and Technology (NIST), propose to identify working fluids for supercritical and trilateral cycles that, when utilized in a binary power block that has been appropriately engineered for a given geothermal site, enable marked increases (20 – 50%) in energy conversion efficiency as compared to currently utilized isopentane, isobutane or refrigerants in a subcritical Organic Rankine Cycle.

Enabling working fluids for trilateral and supercritical cycles will help realize economically viable geothermal power generation from a broader range of resources temperature. Economic power generation from lower temperature source streams will allow development of geothermal energy from larger areas of this ubiquitous renewable resource. Advancements in drilling technology and reservoir engineering will make higher temperature source streams more commonly available.

State New York
Objectives Identify high potential working fluids for any source temperature in the range anticipated for next generation geothermal plants.
Awardees (Company / Institution) GE Global Research
Awardee Website http://www.ge.com/research/
Partner 1 AltaRock Energy, Inc
Partner 2 National Institute of Standards and Technology

Funding Opportunity Announcement DE-FOA-0000075
DOE Funding Level (total award amount) $3,000,000.00
Awardee Cost Share $750,000.00
Total Project Cost $3,750,000.00

Principal Investigator(s) Helge Klockow

Targets / Milestones - Phase I of the program is the identification of a group of fluids with potential, based on available thermodynamic and thermophysical property data, to increase power generation efficiencies in EGS applications when used as working fluids in trilateral and/or supercritical cycles. In the process of identifying this group of high potential fluids, a cycle performance model will be built based on thermodynamics and expertise in hardware selection for cycle design.

- Phase II results in the development of an economic model that predicts the costs of a next generation geothermal power plant. A next generation plant utilizes one of the high-potential working fluids in an advanced binary cycle using heat mined from an EGS reservoir. Costs of reservoir engineering and management will be captured in the cost estimate. The cost model will be integrated with the performance model developed in Phase 1. In parallel to the development of an integrated thermoeconomic model, the impact of uncertainty in fluid property data on the design of the pump, heat exchangers, and expander will be gauged. Specifications on the required accuracy of fluid property will be determined.

- Phase III is largely experimental. The most promising combination of fluid and cycle will be selected based on the anticipated range of resource temperatures at the chosen EGS site. Thermodynamic and thermophysical property data of the chosen working fluid will be measured with required accuracy and used to design hardware components of the corresponding cycle. A pilot-scale power block will be designed, constructed, and used to validate performance predictions of the chosen working fluid in the corresponding advanced cycle. Completion of this validation phase concludes the program.

Location of Project Niskayuna, NY

Impacts If successful, new working fluid could increase energy conversion efficiency in binary power plants.
Funding Source American Recovery and Reinvestment Act of 2009
References EERE Geothermal Technologies Programs[1]


  1. EERE Geothermal Technologies Programs