Friday, February 10, 2017

USA: Successful Code Comparison Study for Geothermal

Two Brains are Better Than One: How the Geothermal Community Upped the Game for Computer Codes (PNNL)

Modeling an underground world of uncertainty requires collaboration

The GTO-CCS team brought 11 research institutions together to collaborate on coupled thermal, hydrologic, geomechanical, and geochemical numerical simulators. These codes have the potential to help facilitate widespread geothermal energy development. (Courtesy PNNL)
High upfront installation costs create a barrier to fast, widespread deployment of geothermal power plants. The initial cost in U.S. for a large field and power plant is around $2,500 per installed kW and upwards of $5,000/kWe for a small (<1Mwe) power plant. Most of the cost comes from drilling the geothermal wells and creating a successful geothermal reservoir. Since it’s difficult to “see” below the earth’s surface, geothermal developers rely on computer codes called numerical simulators. These codes reduce the uncertainty around where production geothermal wells should be drilled and the flow and thermal recovery characteristics of the reservoir. They also prove to be extremely valuable because of their ability to simulate how a reservoir can be created and sustained, how flow will change over time, the impacts of stimulation and circulation, and ultimately may predict a reservoir’s power generation capability.

Several computer codes exist, but not all codes are created equal. To better understand discrepancies between the codes and improve geothermal models, the DOE’s Geothermal Technologies Office (GTO) initiated a Code Comparison Study. Led by Pacific Northwest National Laboratory (PNNL) engineer Mark White, the GTO Code Comparison Study brought together 11 research institutions to test, compare, improve, and discuss their codes. For more information check out the Benchmark Problems of the GTO Code Comparison Study (PDF).

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