Simon Pollock
Technical Director - Planning | Sector Lead - Renewables
Pumped hydro: the missing link for clean energy success
RPS National Renewables Lead, Simon Pollock explains why Australia should be paying more attention to pumped hydro.
Simon Pollock
Storage solutions for renewable energy
We all know that the success of a fully renewable energy system rests on a guarantee of supply, and resilience. In the past, this was rarely a problem as coal-fired generation operates on a baseload power model. But as we move into the era of renewables where the supply of solar and wind energy is inherently intermittent, our network must incorporate both diversity of energy sources, and effective storage solutions.
Building in storage means we maximise the value of the electricity we generate from renewables. We can deploy stored energy when demand on the network is greatest, and keep the lights on even when the wind isn't blowing, and the sun isn't shining. The industry is making huge leaps with battery storage technology. But there is another storage option that is receiving renewed consideration and momentum as the sector pursues its energy security goals – and that’s pumped hydro.
Pumped hydro: a water battery
A closed system, pumped hydro consists of two dams – one sitting higher than the other – and utilises the benefits of gravity to generate hydroelectricity via a turbine tunnel. Water is pumped from the bottom reservoir to the top when power from another source (like solar) is readily and cheaply available. While the solar energy might be expended for pumping, its potential is stored in this ‘water battery’ to be used when the network needs it.
When demand for energy from solar (or other renewables) outstrips supply, water from the top reservoir is released back into the lower one, effectively reconstituting electricity on the way down. It can therefore help solve the intermittency challenges that still exist for maturing renewable generation asset classes like solar and wind.
The untapped potential of the dam system
Pumped hydro has untapped potential in this country. The Australian National University has created a global pumped hydro atlas, identifying 616,000 potential sites around the world suitable for pumped hydro energy storage. There are 3,000 or so potential sites around Australia.
In 2020, the Australian Government stated that the number of potential sites in this country offers an opportunity for developers: “The potential pumped hydro energy storage resource is almost 300 times more than required. Developers can afford to be very selective since only about 20 sites (the best 0.1% of sites) would be required to support 100% renewable electricity generation.”
Addressing pumped hydro challenges
While there are pumped hydro proposals in the pipeline – Pioneer-Burdekin, Borumba, Oven Mountain, and Kidston to name a few – one of the key barriers to investment in this asset class is the long lead time needed to bring projects online.
Considerable environmental impact assessments and studies are required, and pumped hydro projects need sustainable water sources to fill and maintain the dam system. But, as the Australian National University points out, the water requirements of a renewable system with pumped hydro, wind and solar is far less than for a similar coal-based system. And, where evaporation might be an issue, suppressors can be used to reduce the loss.
An integrated approach for renewable energy
A number of developers are looking to pumped hydro as a mechanism for ‘smoothing’ their energy offer or powering their businesses and projects. Some are beginning to work together to develop solar, wind, pumped hydro and green hydrogen in close proximity, building ‘green’ industrial power plants, of sorts. Such an approach – where different renewable generation sources are integrated – adds value and supports the viability of the others. It’s something that we should be looking to replicate around the country.
As each state and territory moves to meet net zero targets, there must be clever and systematic planning for how each piece of the renewables puzzle comes together. There is a lot to like about pumped hydro. It can store a lot of energy, its renewable, and it can be called on when needed. Now is the time to talk about it more.
