Unlocking deep superhot rock resources through millimeter wave drilling technology

Super Hot Rock (SHR) represents a renewable energy resource with a power density comparable to fossil fuels, an order of magnitude improvement relative to typical geothermal systems. The overwhelming majority of SHR resources are stored in deep continental crust, accessible to 80% of the world's major population centers at depths ranging from 10 - 20 km. Accessing this Deep SHR resource requires a novel drilling approach that can leapfrog the current limitations to deep mechanical drilling: Millimeter-Wave (MMW) Drilling. Pioneered at MIT and leveraging technology developed for nuclear fusion research, MMW Drilling represents a non-contact, direct energy drilling approach that replaces mechanical drilling with a full bore vaporization approach. High-powered Radio Frequency energy is efficiently transmitted downhole to result in a dielectric heating interaction, rapidly sublimating the rock before the quenched vapors are conveyed up-hole by a circulating purge gas in a manor analogous to air drilling. MMW Drilling can avoid the high temperature, high pressure limitations on current drilling technology while improving drilling rates of penetration for deep formations by an order of magnitude, enabling Deep SHR at a global scale. In this paper, we explain the MMW drilling concept and why it's an optimal approach to access Deep SHR, provide justification through simple economic models, and demonstrate the technical feasibility by presenting recent results from a lab experimental campaign at Oak Ridge National Laboratory (ORNL).