The landscape of Australia’s electricity network is undergoing significant transformation, largely driven by the importance to decarbonise and the closure of aging coal-fired power plants. This shift entails a greater reliance on variable electricity generation sources – solar energy output varies with the intensity of sunlight, while wind turbines only produce electricity when the wind blows.

Pumped Hydro Energy Storage enables the ability to store renewable electricity generated from these sources and utilised during periods when the Australian population would have typically depended on coal fired generation – facilitating a smoother transition towards renewable energy utilisation.

There are two main types of pumped hydro:

• Open-loop: with either an upper or lower reservoir that is continuously connected to a naturally flowing water source such as a river.
• Closed-loop: an ‘off-river’ site that produces power from water pumped to an upper reservoir without a significant natural inflow.

Both of our projects will be using a Closed-Loop system.  Water is borrowed from the lake to fill the upper reservoir, charging the battery, and then returned to the lake during energy production.

No, the projects operate as closed-loop systems, continuously utilising and replenishing the existing dam water without any net loss or addition to the water source.

Yes, and like all forms of energy storage, there are inherent efficiency losses.  But electricity is not the same value at all times of the day. However, pumping water offers us the capability to absorb surplus energy during off-peak periods, storing it in the upper reservoir, and subsequently releasing it to generate power when needed.

For instance, during the height of solar generation in the midday when electricity prices are low, or even negative, and many are away at work or school, we can store the excess solar energy by pumping water to the upper reservoir. Then, as the sun sets and demand surges in the early evening when people return home, water can be released downhill again so the stored energy can be utilised to meet this peak demand.

Ensuring electricity availability on demand, often referred to as baseload, is a universal priority. Historically, Australia has relied heavily on coal-fired power generation to meet its baseload electricity requirements. However, with many coal-fired power stations nearing the end of their operational life, there’s a pressing need to compensate for these losses with alternative sources.

Environmental, social, and economic considerations have all underscored the importance of transitioning to renewable energy generation. Supporting these variable generation sources necessitates energy storage solutions capable of capturing and releasing energy to the electricity grid as per the needs of the Australian population, rather than solely relying on when it can be generated.

During periods of high energy production but low demand within the National Electricity Market (NEM), generators are often constrained by the network operator due to the lack of capacity for surplus electricity. Our projects are specifically designed to address this issue by absorbing excess energy, enabling wind and solar generators to maintain their electricity generation.  Subsequently, this stored energy can be reintegrated into the NEM when demand rises.

The upper reservoir will represent about 1% of the capacity of Glenbawn and 3% of the capacity of Lake St Clair and for that reason it is expected that the projects will have a minimal impact on the water levels of the lakes, Furthermore, no adverse effects on recreational activities on the lakes are currently anticipated.

There will be a detailed preliminary design phase that will consider the concept in greater detail. This may include engineering design, geotechnical investigations and developing a greater understanding of environmental and social dimensions of the design. The preliminary design will consider matters that will be required by the NSW government under the Environmental Planning and Assessment Act 1979 (EP&A). As the level of detail and knowledge increases, the UHH team will engage with the broader community to gather social information and views; these will be key inputs into the EP&A process.