As the world transitions towards renewable energy sources and pathways toward net zero, Idemitsu Australia is conducting feasibility assessments and developing renewable power projects to provide a variety of renewable energy power sources and energy storage options.
Idemitsu Australia recognises the role it must play in helping the world achieve its decarbonisation ambitions and the part it plays in its parent company’s, Idemitsu Kosan’s, medium-term decarbonisation plans as well as its overarching long-term target to reach net zero CO2 emissions from Idemitsu Kosan Group’s operations (Scope 1 and 2) by 2050.
We are proud to invest in sustainable energy development in Australia and are currently advancing our investigations and developments in solar, biofuels and e-fuels, green hydrogen and ammonia.
Our global renewable energy expertise will help us to deliver projects that create domestic and export energy opportunities, and our current projects include:
- Pumped Hydro Energy Storage (PHES) project providing up to 400MW with 8hrs of energy storage (3,200MWh) in Muswellbrook in partnership with AGL.
- Muswellbrook Clean Industries Precinct which will incorporate pumped hydro and solar, and continuing investigations into green hydrogen, energy storage technologies and co-locating clean industry users of these energy sources.
- Merriown solar farm, a 6.5MWp/4.95MWac behind the meter solar farm completed in 2025 and will supply green electricity to Boggabri Coal Mine, sufficient to meet 100% of the daytime load requirements.
Muswellbrook Pumped Hydro
As Australia transitions to include more renewable energy sources, hydroelectric energy storage can provide large amounts of long duration storage to keep electricity running and is shaping up to be a critical part of our future energy system.
The proposed Muswellbrook Pumped Hydro Energy Storage (PHES) facility, in partnership with AGL, is exploring an innovative model whereby an existing mine void at Idemitsu Australia’s Muswellbrook coal mine acts as the lower reservoir and nearby Bells Mountain is proposed as the location for the upper reservoir. The pumped hydro system will provide capacity of up to 400MW with 8hrs of energy storage (3,200MWh).
The project is located within the Hunter-Central Coast Renewable Energy Zone and is being developed to provide deep energy storage to underpin the reliability of the NSW electricity grid and support the transition to low emission generation technologies, such as wind and solar PV.
In 2022, Muswellbrook Pumped Hydro Pty Ltd, was awarded $9.45 million funding under the NSW Government’s Pumped Hydro Recoverable Grants Program to advance development studies to a stage where the project is ready for investment. The grant funding is being used to complete a targeted geotechnical due diligence program, detailed project design and connection studies to prepare the project for an investment decision.
In 2024 the Project was declared a Critical State Significant Infrastructure project by the NSW Government. This recognises the critical role that Muswellbrook Pumped Hydro could play in providing essential long-duration storage for the NSW electricity grid.
Muswellbrook Clean Industries Precinct
After 115 years of continuous operation, the Muswellbrook Coal Mine completed mining and entered rehabilitation, creating an opportunity to transition the site to a future beyond mining.
Going beyond closure requirements, Idemitsu is developing the Muswellbrook Clean Industries Precinct as a hub for clean energy and industrial activity, supporting long-term jobs and economic growth in the Upper Hunter Region.
The precinct includes development-phase projects such as the Muswellbrook Solar Farm and the Muswellbrook Pumped Hydroelectric Storage project, with capacity to host additional energy generation and storage technologies, as well as research, training and industrial facilities.
A significant proportion of the site will be dedicated to Biodiversity Stewardship Areas, ensuring environmental outcomes are embedded alongside regional development.
Muswellbrook Solar Farm and Battery
The Muswellbrook Solar Farm and Battery (BESS) was developed by Idemitsu Australia in partnership with OX2. The project includes a 135MWac solar farm and a 100MWac, 2-hour (200MWh) BESS, designed to generate enough electricity to power approximately 52,310 homes.
Located on former coal mine buffer land, the project serves as an early example of the energy transition in the Upper Hunter Region. The Muswellbrook Solar Farm and BESS is currently progressing to the construction phase following a NSW State Significant Development (SSD) approval.
Merriown Solar Farm and Battery
Idemitsu Australia has installed a solar farm at the Boggabri Coal Mine on the Merriown property. Owned and operated by Boggabri Coal Operations, the solar farm supplies up to 5MW of renewable electricity for use on site.
Construction commenced in Q4 2024, With the project successfully commissioned in September 2025, the solar facility now generates up to 5 MW of renewable energy during daylight hours, enabling the mine to operate on renewable power during the day and supporting future electrification initiatives. In its first year of operation, the project is expected to reduce CO₂ emissions by approximately 5,000 tonnes.
To further strengthen energy reliability, Idemitsu Australia is developing a 12.6 MWh vanadium redox flow battery system to be co-located with the Merriown Solar Farm. The battery will provide up to 6.3 hours of energy storage and is scheduled for completion in late 2026.
Once operational, the battery will optimise solar generation, reduce reliance on the grid, and support more sustainable, low-emissions mining operations.
