Goal
Access deep geothermal heat by vaporizing basement rock with high-power millimeter-wave (gyrotron) radiation.
Problem
Conventional mechanical drilling cannot economically reach the hard basement rock at depths > 5 km where temperatures are high enough for supercritical geothermal energy.
Concept Summary
A gyrotron generates high-power millimeter-wave radiation that is guided down a metallic waveguide into the borehole. The waves dielectric-heat and vaporize the rock, creating a melt front that advances the borehole. A circulating gas flushes the resulting ash to the surface. The system is used after conventional rotary drilling through the sedimentary layer, enabling drilling to depths of up to 20 km and temperatures of ~500 deg C, vastly increasing geothermal energy density.
Principles
- Dielectric heating of rock (microwave oven principle)
- High-power millimeter-wave (gyrotron) radiation
- Waveguide transmission of electromagnetic energy
- Gas-flushed ash removal
Scientific Domains
Materials
- Metallic waveguide (copper/steel)
- Gyrotron vacuum tube components
- Inert flushing gas (e.g., argon, nitrogen)
- Basement rock samples (granite, basalt)
Mechanisms of Action
- Absorption of millimeter-wave energy by rock -> rapid heating and vaporization
- Creation of a melt front that propagates downhole
- Circulating gas transports vaporized material to the surface
Energy Sources
Applications
- Deep geothermal power generation
- Supercritical steam production for electricity
- Mining of high-temperature geothermal resources
Claimed Performance
Drilling depths up to 20 km, temperatures up to 500 deg C, ten-times the energy density of conventional geothermal, and a 100x increase in penetration rate compared with baseline tests in 2023-2024.
Experimental Evidence
Field test outside the lab in 2023-2024 demonstrated the first open-sky millimeter-wave drilling operation, reaching the 100x target penetration rate. Laboratory experiments at MIT's Plasma Science and Fusion Center vaporized granite and basalt blocks using a gyrotron. Multiple patents (US2024254838, WO2024144961, US2025067171, etc.) describe the apparatus and monitoring methods.
Replication Status
Field testing performed by Quaise Energy; no independent third-party replication reported.
Limitations
- Requires very high electrical power input
- Less effective in softer sedimentary formations (hybrid approach needed)
- Waveguide durability at extreme temperatures and pressures not yet proven
- Economic cost of gyrotron system at commercial scale remains uncertain