For more than three decades, Dr. Mark White has been developing numerical simulators, termed STOMP, for modeling multiphase subsurface flow and transport processes across a spectrum of application areas at Pacific Northwest National Laboratory. Recent modeling developments have been directed at embedded fracture and borehole capabilities, with direct applications in enhanced and closed-loop geothermal systems. Dr. White previously led the GTO Code Comparison Study, and is currently serving as the lead for the Modeling and Simulation Working Group of the EGS Collab project and as the lead for the Closed Loop Geothermal Working Group. Dr. White’s first modeling presentation was in 1980 and addressed the performance of a passive solar Trombe wall.