Hydroelectricity (also known as 'hydro') is a well-developed renewable energy technology that has been around for more than a century.

Hydro uses flowing water to spin a turbine connected to a generator that produces electricity. The amount of electricity generated depends on the volume of water and the height of the water above the turbine.

Large hydroelectric power stations need dams to store the water required to produce electricity. These dams are often built to hold irrigation or drinking water, and the power station is included in the project to ensure maximum value is extracted from the water.

Hydroelectricity does not actually consume any water, as all the water is returned to the river after use.

While hydro plants can have very large capacities, the amount of electricity they generate can vary markedly from year to year depending on rainfall and electricity demand. Hydro can provide both baseload and peakload electricity, and hydro generators can start up and supply maximum power within 90 seconds.

Smaller hydroelectric power stations (called mini or micro hydro) do not generally need dams but rely on naturally flowing water such as streams. These provide a good source of power and are often used as stand-alone systems not connected to the main electricity grid.

Hydroelectricity in Australia: 2017 in focus

Hydro power accounted for 33.9 per cent of the renewable electricity produced in Australia in 2017. There are more than 120 working hydro power stations in Australia, with most of the nation's hydroelectricity generated by Hydro Tasmania's network of power plants and the Snowy Mountains Hydro Scheme in New South Wales.

Overall hydro output was down in 2017 compared to the previous year. According to Hydro Tasmania, the lower generation was principally due to below average rainfall in catchment areas compared to the year before.

The future of hydroelectricity in Australia

The Australian National University (ANU) has identified 22,000 potential pumped hydro sites across Australia. So many good quality pumped hydro sites were identified that the ANU says that only the top 0.1 per cent of these would be needed to provide the necessary support for a 100 per cent renewable energy system in Australia.

The Tasmanian Government's 'Battery of the Nation' initiative is investigating and developing pathways of future development opportunities that would allow Tasmania to make a greater contribution to the National Electricity Market. Initial studies have identified significant pumped hydro potential in the state, potentially delivering up to 2500 MW of energy – nearly doubling Hydro Tasmania's current capacity.

The Snowy 2.0 expansion and the Battery of the Nation proposal clearly show there is significant interest in expanding the nation's hydro resources to provide additional storage capacity to complement renewable energy such as wind and solar power.

Sources:

  • IES
  • Clean Energy Council Renewable Database
  • Clean Energy Australia Report 2018