Chiyoda and Sage Geosystems to study high‑pressure surface facilities for commercial EGS

Agreement and study scope

Chiyoda Corporation and Sage Geosystems have signed an MOU to carry out a technical and commercial feasibility study of high‑pressure surface facilities required for a commercial‑scale power generation system using Sage's proprietary enhanced geothermal systems (EGS) approach. Chiyoda will assess major equipment configuration, power and energy balances, and provide indicative capital, operating cost and power generation cost estimates using wellhead pressure, temperature, fluid properties and operating conditions supplied by Sage.

Technology

Sage's EGS injects water into an engineered underground reservoir in hot rock and leverages both subsurface heat and the reservoir's stored pressure energy. Produced fluid flows back to surface while limiting pressure and water loss, which increases plant efficiency and project economics. The approach is also being advanced for long‑duration energy storage by using surplus electricity to store pressure energy underground for later recovery.

Applications and advantages

Unlike conventional geothermal that depends on naturally occurring steam or hot water and is geographically limited, EGS applies drilling, well construction and reservoir management techniques from the oil and gas sector to broaden deployable locations. The technology is positioned to provide stable, low‑carbon baseload power for data centers, industrial facilities, microgrids and critical infrastructure.

Support and next steps

The Study has been selected for support under Tokyo's TIB CATAPULT program and aligns with the Zero Emission Tokyo Strategy. Chiyoda and Sage will continue technical and business evaluations to progress toward commercial‑scale deployment and realise gigawatt‑scale power generation and long‑duration storage.