Muswellbrook Pumped Hydro Project, Australia

The Muswellbrook Pumped Hydro Energy Storage Project is a pumped hydro facility proposed to be developed in New South Wales (NSW), Australia.

The project will have a production capacity of up to 500MW providing up to eight hours of energy storage.

It will be developed by a joint venture between AGL Energy and Idemitsu Renewable Developments Australia.

Initially, the project was conceived with a production capacity of 250MW. Later the planned capacity was increased up to 500MW upon further consideration.

The construction of the Muswellbrook pumped hydro facility is expected to commence in 2026, subject to final investment decision and government approvals. It will be completed in 2029.

The project will create 250 jobs during construction and 20 roles during operations.

The development of the project will support NSW Government in its strategy to transition to energy generation from renewable sources.

Muswellbrook Pumped Hydro Project Location

Muswellbrook Pumped Hydro Plant will be developed in the Muswellbrook Local Government Area, approximately 4km northeast of Muswellbrook town in NSW.

The project components will be located within the Muswellbrook Coal Company (MCC) mine site and Bells Mountain, along with adjoining buffer lands.

The project would be accessible via Sandy Creek Road which intersects with the New England Highway to the southwest of the project.

Background

In September 2022, the joint venture between AGL and Idemitsu Australia signed a A$9.45m funding agreement with the Energy Corporation of New South Wales.

The funding, awarded under the state government’s Pumped Hydro Recoverable Grants Program, enabled the JV to advance with the development studies for Muswellbrook Pumped Hydro Project.

In the same year, the Muswellbrook Coal Mine ceased operations.

In December 2023, the joint venture submitted a Scoping Report for the project to the Department of Planning and Environment of New South Wales for the Secretary’s Environmental Assessment Requirements (SEARs).

In February 2024, the department granted the approval for the project.

Muswellbrook received a Critical Stage Significant Infrastructure status in July 2024 from the NSW Government.

The development of the pumped hydro facility is estimated to cost around A$650-700m ($407m-$438m).

Muswellbrook Pumped Hydro Project Infrastructure

The key components of Muswellbrook Pumped Hydro Energy Storage Project will include an upper reservoir at Bells Mountain, a lower reservoir within an existing MCC mine void, water pipeline (penstock) connecting the two reservoirs, hydroelectric turbines to generate electricity and a connection to the existing Muswellbrook 330kV substation.

Other ancillary supporting infrastructure including water offtake pipeline from the Hunter River, internal access roads, site office and small workshop buildings among others.

The upper reservoir will be developed on freehold land that will be acquired by AGL Energy if the project proceeds. The current plan will impact two separate freehold properties.

The upper reservoir will include an approximate area of 48ha, while lower reservoir will have a footprint of 50ha.

The project will include up to four hydro-electricity generation units along with water and access tunnels, surge tanks and inlet and outlet structures.

Both reservoirs would be connected by a 2.1km of waterway comprising of tunnel and surface penstock.

As part of the project work, construction activity will include switchyard, transformers, auxiliary electrical and mechanical buildings, control room and laydown areas.

A 1.5km transmission line will connect the project switchyard with TransGrid’s existing Muswellbrook 330 kV substation.

The waterway will comprise a tunnel and surface penstocks which will be located above and below ground.

A 5km long pipeline would be constructed to procure water from the Hunter River and use it to fill the lower reservoir during operations.

Operations

At times when there is a surplus renewable energy or electricity supply, the project will transport and store water in the upper reservoir.

During peak demand hours, water will be released from the upper reservoir to flow via a connected pipeline to hydroelectric turbines to produce electricity. The lower reservoir will then collect the water.

The project will be connected to a 1.5km long high voltage transmission line connecting to TransGrid’s existing Muswellbrook 330 kV substation.

The electricity will be fed into Australia’s National Electricity Market (NEM) with direct transmission links to Newcastle and Sydney demand centres.

Contractors Involved

UK-based engineering, management and development consultancy Mott MacDonald was selected as the Owners Engineer for the Muswellbrook Pumped Hydro Energy Storage project in November 2023.

As part of the contract, Mott MacDonald will help in developing the reference design of main components of the project.

Eagle Vision, a 3D visual creator company, took aerial photography and video footage. This was used to montage the 3D model of the mountain, the reservoirs and the power station waterway pipelines.

SMEC, an Australian consultancy firm, prepared the upper reservoir geotechnical investigation report for the project.