Rethinking EGS: The Single-Well System Challenging Geothermal Limits

In this episode of Geothermal Unleashed, host Elizabeth Cambry interviews Jeff Spray, co-founder of DTS, about his company’s innovative single-well enhanced geothermal system (EGS). Spray explains that unlike conventional EGS which typically requires two or three wells, DTS uses a single vertical well with massive hydraulic fractures extending up to half a mile on either side. The well acts as both injector and producer, with inner tubing returning heated fluid. Key features include flow-diverting barriers to control fluid movement, high sweep efficiency, and reduced parasitic losses. Spray claims the system can deliver up to 30 MW of baseload power from a single well, with potential for seasonal storage. He discusses how the design addresses heat recharge issues by spacing fractures over 1,000 feet apart. The system aims to use flash turbines instead of ORC, eliminating cooling costs. Spray emphasizes that the technology leverages existing oil and gas techniques, such as water conformance, and is ready for commercial deployment pending funding. The conversation highlights potential cost advantages and scalability, though no field demonstrations are mentioned.