Project Phoenix Pumped Hydro Energy Storage Project – Successful implementation of the Engineering Geological Model approach in support of the energy transition

ACEN Phoenix Pty Ltd (ACEN Phoenix) engaged GHD to complete prefeasibility and feasibility investigations on Phoenix Pumped Hydro, a proposed pumped hydropower project in regional NSW. The aim of these works was to develop a thorough understanding of site-related geological and geotechnical hazards early in the project, to guide design and enable more accurate cost estimation, whilst reducing, where possible, the need for intrusive on-site investigations. The Engineering Geological Model (EGM) approach can be used to effectively identify and assess geological relationships and geotechnical properties and provides an important framework to enable thorough understanding of geomechanical behaviour and potential hazards (Schofield and Roberts, 2024). On this project, the conceptual geological model was refined in near real-time as the detailed geological mapping identified and delineated an unmapped complexly folded and faulted dolerite sill intruded prior to regional deformation. The investigations were rescoped to provide confidence in the interpretation and hence allowing design optimisation to exploit more favourable geotechnical conditions.

This project demonstrates the benefits of the use of fundamental geological skills as part of the Engineering Geological Model approach in large civil engineering projects to optimise design and deliver both time and cost savings through appropriate and scientific targeting of intrusive investigations.