A $1.8 billion clean energy hub proposed for the site of a former Gloucester coal mine could be operating as early as 2029.
An environmental impact statement for the The Stratford Renewable Energy Hub says the project would create 350 construction and 10 ongoing jobs.
Mining company Yancoal first outlined plans for the hub earlier this year following the completion of operations at the Stratford Mining Complex.
The hub would include a 300 megawatt / 3600 megawatt hour pumped hydro energy storage system, which would use the mine's existing dams and water supply.
It would also feature a 300 megawatt solar farm, which would provide a portion of the energy to recharge the pumped hydro during daylight hours when there is excess renewable electricity already in the grid.
The renewable energy generated by the project would be the equivalent to the daily consumption of approximately 140,000 to 180,000 households.
"The project would add to the supply of renewable energy in the electricity grid, and contribute to state and national emissions reduction targets to address climate change," the environmental impact statement summary says.
"With the scheduled closure of NSW's existing coal-fired power stations, long duration storage projects have been identified as being critical to complement variable renewable energy sources (such as solar and wind) and address electricity reliability standard shortfalls forecast by the Australian Energy Market Operator."
All freehold land required for the project is owned by Yancoal or its subsidiaries.
About 60 per cent of the proposed solar farm footprint is on land previously disturbed as part of the Stratford Mining Complex, with 36 per cent outside the Stratford Mining Complex on land mapped as non-native vegetation due to prior clearing for agriculture.
The project would utilise existing mine infrastructure, including existing car parks, roads, offices, workshops, laydown areas, services and utilities and upgrade the existing Stratford East Dam for the pumped hydro lower reservoir.
"Locating the project at the Stratford Mining Complex has a number of strategic advantages as the project can use and repurpose existing Stratford Mining Complex disturbance areas, infrastructure and water stored in mine voids," the environmental impact statement summary says.
In addition, the project is close to existing transmission infrastructure and established transport routes.
"These strategic advantages of the project site avoid and minimises environmental impacts, particularly when compared to alternative large-scale renewable energy projects located in remote locations."
A company, owned by former prime minister Malcolm Turnbull and his wife Lucy, recently won a tender to develop plans for two pumped hydro projects in the Upper Hunter.
WaterNSW has awarded a development agreement to Upper Hunter Hydro (UHH) to explore the feasibility of the projects using WaterNSW land and reservoirs in the Hunter Valley.
The pumped hydro projects, which would deliver long duration storage totalling more than 1.4 gigawatts for eight to 12 hours, could power a million homes.
UHH has been granted access to the Glenbawn Dam and Glennies Creek Dam as part of its investigation.