Idemitsu Australia and AGL are preparing to embark on a huge construction project at the former Muswellbrook Coal site.
The Muswellbrook Pumped Hydro project has been in the planning since 2019, and in July received Critical State Significant Infrastructure status (CSSI). The project will be located on the former Muswellbrook Coal site where mining ceased in late 2022 after 115 years of operation in the Upper Hunter.
Through a joint venture, AGL and Idemitsu Australia are proposing to create 400 megawatts of energy generation with 8 hours of storage utilising an existing mine void for the lower reservoir and Bells Mountain for the upper reservoir.
Also included in the proposal for the former mine site is the Muswellbrook Solar Farm. Company OX2 has joined Idemitsu Australia for that venture and proposes a large-scale solar facility at the site.
The pumped hydro project is by far the more ambitious of the two. It works by circulating water from a lower reservoir into an upper storage reservoir. Upon demand, water is released from the upper storage site and uses gravity to turn turbines and generate electricity.
The project would be located within the Hunter Central Coast Renewable Energy Zone and has been awarded $9.45 million in funding under the NSW Government’s Pumped Hydro Recoverable Grants Program.
Idemitsu Australia’s Head of Renewables Serge Radojevic said the construction of the project will be a huge undertaking.
“You’re building a 100-year asset, so everything must be built to a high specification to stand the test of time.
“The works at Bells Mountain will be a huge undertaking. We have to excavate and build a large reservoir at the top of the mountain and do the tunnelling and building of underground pipelines to connect the upper and lower reservoirs. Then the turbine powerhouse needs to be connected to those pipelines and installed in a cavern-like structure deep underground.
“So, the length of tunnelling and the excavation and civil works will be tremendous.”
The goal is to start construction in 2026, with first generation targeted for 2029.
Serge said the pumped hydro project is being designed to minimise impact on the community.
“The pipelines and turbines are all underground so the visual impact will be minimal as it essentially ends up being two water reservoirs, one at the top of Bells Mountain and one at the former mine site.
“From an investment perspective, there is a huge opportunity for investment into post mining land use for the community’s benefit that wouldn’t have happened otherwise.
“Long duration energy storage like pumped hydro presents a really good opportunity to put downward pressure on electricity prices and help make access to affordable electricity a reality.”
The Muswellbrook Solar Farm is closer to its final investment decision and if achieved construction would start in 2025 to be operational in 2026.
The hydro project will create 250 construction jobs over four years and when it’s operational will support around 20 ongoing jobs. While the solar project will peak at 200 construction jobs and once complete will maintain about six operations jobs.
Serge said there are still plenty of approvals to work through, but they are confident in both projects.
“The CSSI is a good win for the Muswellbrook Pumped Hydro project, it streamlines your pathway and makes your timelines and approval processes clearer.
“The CSSI is also good for the public to see. They can see the project has the support of the Government that is reserved for a very select number of projects and is being taken seriously.”
