May 29, 2023

EnergyAustralia, owner of the Mt Piper Power Station, confirmed it is seeking approval for an extension of geological exploration work at the site of its proposed Lake Lyell Pumped Hydro Project to support the technical and environmental feasibility assessment of the project. 
In addition, the company has made a separate development application for subsurface site investigation works as part of the proposed grid scale Mt Piper battery project.  These works will help inform the project’s approach to suitable siting, design and environmental management.  

Both projects are at an early stage. Feasibility investigations for the Lake Lyell project will continue throughout 2023 and 2024 before a final decision is made on the project's advancement. This will include a period of extensive community consultation on the proposed project. 
Energy storage projects are an important part of New South Wales clean energy transformation providing reliable energy at times of high energy demand or when there is little sun or wind to power renewable energy generation.
Over the past six months, the Lake Lyell project team has drilled eight exploratory geological boreholes to better understand if ground conditions will suit potential development. 13 additional boreholes are now needed to gather further geotechnical information and to establish a comprehensive groundwater monitoring program.
Project Director Virginia Burns said: “Large civil projects require careful planning. Accurate geological data will be critical to understanding if Mount Walker’s geology would allow a pumped hydro energy storage to be built on the land owned by EnergyAustralia. 
“The proposed new drilling works will be substantially the same as works originally approved by the Lithgow City Council and will result in minimal environmental impact. 
“The drilling program will be subject to regular environmental compliance audits including regular inspections at all drill sites. The work undertaken so far has meant roadway works for site access and a small area of bush being cleared at the drilling sites. There have been no impacts on waterways.”
If approved by Council, new geological exploration works will commence in June and take three to five months to complete.  
Data collected throughout the full drilling program will be used to assess the technical and environmental feasibility of the project. Information on the geotechnical investigation will be incorporated into the project’s detailed Environmental Impact Statement which is expected to be released for public review and comment in 2024.
If approved, the Lake Lyell Pumped Hydro Project would utilise water from the existing purpose-built Lake Lyell dam and a new purpose-built upper reservoir on the southern flank of Mount Walker to produce a nominal 350 megawatts (MW) of clean energy – enough power to supply over 150,000 NSW households for up to 8 hours1
For further information on the project, visit the project website at
1Based on a POE10 demand of 1.97kW for EnergyAustralia’s portfolio of NSW residential customers at 350MW of generation.