The Big-T Pumped Hydro Energy Storage (PHES) Project is a proposed renewable energy project located at Lake Cressbrook, approximately 45km north-east of Toowoomba.

The Project has a planned generating capacity of 400MW (megawatts) of hydroelectricity, with 10 hours (which is 4GWh) of storage.

The Project also includes a first of its kind co-located 200MW/1 hour Battery Energy Storage System (BESS).

PHES projects are large-scale water batteries that store energy. PHES systems pump water uphill to an elevated reservoir when electricity demand is low, usually in off-peak periods. When electricity demand is high, water is released from the upper reservoir to power a turbine to generate renewable electricity.

Closed loop PHES systems such as the Big-T Project do not consume water, they operate by recirculating water between the lower and upper reservoirs.

The Project was declared a Coordinated Project by the Coordinator-General in September 2022 under the State Development and Public Works Organisation Act 1971.

Primary consultation has occurred with Toowoomba Regional Council as Lake Cressbrook’s primary landowner, and the Project has progressed to Stage 3 of Council’s Invitation to Tender (ITT) process for development of commercial terms.

A reference design has been completed in Q3 2024 accompanied by a further feasibility assessment.

As at Q2 2025 An Environmental Impact Statement (EIS) is being prepared for lodgement, and stakeholder and community consultation and engagement activities have commenced. The draft EIS will be publicly notified and the public (including government agencies) will have an opportunity to have their say on the project and its impacts (positive and negative).

Engagement with representatives of the Western Wakka Wakka community has occurred throughout the project development process. An Aboriginal Cultural Heritage Due Diligence Assessment Study has been completed, and a Cultural Heritage Management Plan (CHMP) has also been completed and is in place.

The Big-T Project has a funded cost of over $1.65 billion and will bring significant social and economic benefits to the Toowoomba and Somerset regions such as:

• Potential savings for QLD power customers of up to $1.2 billion (based on 2022 electricity trading data).
• Commitment to utilizing up to 70% local Australian content.
• Creation of 250-500 construction jobs and 30+ permanent operational roles.
• Local employment and investment boost in the Toowoomba and Somerset Regional Council areas.
• Economic uplift for local businesses through supply chain and procurement opportunities.
• Infrastructure enhancements, including local utilities and road upgrades.
• Strengthened economic support for local entities, boosting patronage for sports, recreation, and cultural clubs.
• Positive branding of the city, aiding in regional growth.
• Contribution to achieving the Queensland Renewable Energy Target

A variety of initiatives to reduce environmental impact, protect native flora, fauna and local vegetation, reduce visual impact, and negate bush fire risk have been introduced, including relocation of the upper reservoir to lower ecological value land, and the power plant and associated infrastructure to be underground.

In accordance with the Environment Protection and Biodiversity Conservation Act 1999 and Queensland Biodiversity Offset Policy guidelines, the project proposes to implement an associated biodiversity offset project, meaning it will create replacement habitat of three to five times the area impacted by the project.

Maintaining the integrity of Lake Cressbrook reservoir infrastructure and the safety in design of project infrastructure is critically important; the Project is designed fit-for-purpose to industry best practice and to all  Australian standards for a minimum engineering life of 80+ years.

The project will involve an upper reservoir being constructed on privately owned land, with the lower reservoir using Lake Cressbrook.

The electricity connection involves construction of buried electrical cables from the project’s underground power station to Powerlink’s Tarong to Middle Ridge transmission line. The electricity connection is to be partly built under the existing road easement of Sebastapool and Three Mile Roads.

Water usage will adhere to a commercial bulk water agreement to be established with TRC.

We are currently conducting an assessment to determine the baseline water quality in Lake Cressbrook. Should the water quality be affected, either during construction or operations, the project commits to compensating TRC for any extra water treatment costs.

The operational levels (both upper and lower) proposed by TRC for the power plant will be incorporated into the relevant agreements.

The Big-T Project is located in the Queensland Government’s Southern Renewable Energy Zone (QSREZ), identified by the Australian Energy Market Operator (AEMO) in its 2022 Integrated System Plan (ISP) as one of the the preferred location for future renewable development for southern Queensland.

The Project is one of the lowest-cost PHES opportunities available in Australia and has the capacity to power the equivalent of 288,000 homes.

The Project will connect to the National Electricity Market (NEM) through a 15km high voltage transmission line.

Once operational the Project will be an enabler of new renewable energy projects (wind and solar) of 3,000–5,000MW  within the QSREZ, and will assist the Queensland Government to achieve its target of 50% renewables by 2030.

• BE Power is the principal project originator and developer who have partnered with GE Renewable Energy to develop, construct, and operate the project. BE Power develops, finances and operates renewable energy power plants and also undertakes electricity trading and retailing activities.
• GE Vernova is the co-development partner who will develop, construct, and operate the project. GE Vernova is a $15 billion business with one of the broadest portfolios in the renewable energy industry including onshore and offshore wind, blades, hydro, storage, utility-scale solar, grid solutions, hybrid renewables, and digital services offerings.
• Tractebel/Lomabardi are the reference design and EPC documentation contractors. Lombardi and Tractebel are engaged internationally with major pumped hydro schemes and within Australia on the Snowy 2.0 Project.
• Toowoomba Regional Council (TRC) is Lake Cressbrook’s primary landowner. The project is a submission as part of TRC’s New Energy Generation Project Invitation to Tender (ITT) process, which has progressed to Stage 3 for development of commercial terms.

The Project will create approximately 250-500 jobs during the construction phase, and approximately 15-30 ongoing jobs during operation. To accommodate the construction workforce, a temporary accommodation camp is proposed to be established at 7572 New England Highway Crows Nest, with access from Hirning Street (the existing caravan park access road) and approximately 900 metres from the entrance to the Project access road via Albert Street, off the New England Highway.

Bordering the Crows Nest Tourist and Caravan Park, the proposed temporary accommodation camp will feature:

• Temporary self-contained camp accommodation facilities for up to 200 workers
• Access to power and water from existing established services
• Onsite parking
• Septic grey water waste system.

No, the project will not take water from Lake Cressbrook.
Additionally, Toowoomba Regional Council will always have priority access to the water in Lake Cressbrook.
The pumped hydro project would operate by recirculating water daily between the lower and upper reservoirs. This means that during the pumping mode, water would be pumped up-hill from Lake Cressbrook to the upper reservoir, and during the generation mode, water would be released back to Lake Cressbrook through underground hydroelectric turbines to generate electricity.
Modelling indicates there may be small operational losses, with any operational water losses subject to a commercial arrangement with Toowoomba Regional Council.

No. The upper reservoir water would always be available for Toowoomba Regional Council water requirements. It is a key requirement of Council that the project is designed and operated so as not to compromise Toowoomba Regional Council water security or objectives or impact the ability of Council to utilise Lake Cressbrook for drinking water supply at any time.
Lake Cressbrook has a full supply capacity of around 81,000 megalitres (81 gigalitres) with a fluctuation range of approximately 30 metres between minimum operating level and full level supply. The maximum fluctuation from the operation of Big-T is 1 to 2.5 metres. Moreover, the design of the inlet lip height of the upper reservoir limits water usage.

A summary of long-term baseline water quality has been measured at Lake Cressbrook and Cressbrook Creek recording temperature, pH, electroconductivity, dissolved oxygen and turbidity levels, with Lake Cressbrook achieving all recommended guideline levels.
The operation of the project will result in more frequent water level changes in the lake, but it will operate so that the water level stays between agreed operating parameters with the dam owner.
Monitoring programs to assess water quality and aquatic ecological changes in Lake Cressbrook will be implemented during the construction and operational phases of the project with results used to effectively manage and maintain water quality. If it is impacted the project owners will be required to pay for additional water treatment.

The project has been designed to protect the environmental values of the land and associated flora and fauna and would operate in a way to ensure the sustainable, long-term conservation of biodiversity.
A variety of initiatives in the project design will minimise environmental impact; protect native flora, fauna and local vegetation; reduce the project’s visual impact; and negate bush fire risk. These include:

• Locating the power station and water tunnels underground to avoid vegetation clearing
• Using existing tracks where possible
• Relocating the lower intake structure on Lake Cressbrook to minimise the need for new access tracks
• Locating the site office and some logistic laydown areas near the temporary workforce accommodation camp at Crows Nest to minimise the number and size of laydown areas required
• Purchased land at Milford Rocks, Anduramba, for biodiversity offsets, creating replacement habitat that is almost five times the size of the impacted area, as determined under the Environment Protection and Biodiversity Conservation Act. Comprehensive biodiversity offset management will be provided over 20 years. The environmental offset would become a protected area where conservation, sustainability, and growth will remain for future generations.

Independent analysis confirms the proposed Big-T project will deliver significant economic benefits to the Toowoomba, Lockyer Valley and Somerset regions.
During construction, it is estimated the project will contribute an average of $90.7 million per year to the regional economy, create an additional 291 full time jobs across construction, trade and business services sectors, and increase total employee income across the region by an average of $99.7 million per year.
Over its first 40 years of operation, the project is anticipated to create an additional 114 full time jobs, contribute $163.8 million per annum to the regional economy and increase Queensland’s Gross State Product by $7.6 billion.
The project would also deliver approximately $3 billion in additional state and federal government tax revenue and generate approximately $10.1 billion in revenue.
In operation, the project has the potential to lower electricity prices for consumers and will accelerate the region’s transition to renewable energy.

BE Power has made legally binding commitments to cover Council’s costs to manage the ongoing Invitation to Tender process so that the Project will be cost neutral to Council. To date, BE Power has met all of Council’s third-party costs for the ITT process since November 2023 and has committed to meet the costs of the next stage of the process.
In addition, once the Project is operating, it will provide substantial economic benefits to Council through confidential commercial arrangments.

The Big-T is one of the most advanced pumped hydro energy storage projects being developed in Australia. It has been declared a Coordinated Project by the Queensland Office of the Coordinator-General (OCG) under a bilateral assessment with the Commonwealth Department of Climate Change, Energy, the Environment and Water DCCEEW).
The draft Environmental Impact Study (EIS) has been lodged with the OGC and DCCEEW for their review.
Independent technical reports have been completed for the EIS and drafts provided to Toowoomba Regional Council (Social Impact Assessment, Community Engagement and Consultation Report, Economic Impact Assessment).
BE Power and Toowoomba Regional Council have finalised a Project Water Quality Management Plan.
Approval for connection to the electricity grid has been approved by the Australian Energy Market Operator and Powerlink.

As of April 2025, Stanwell Corporation is currently in the process of potentially purchasing the Big-T pumped hydro energy storage scheme from BE Power. The project is well advanced through the Toowoomba Regional Council Invitation to Tender process.