What is hydro energy?

Hydro energy uses the force of moving water to create electricity.

What can hydro energy be used for?

Hydro energy has been harnessed for several centuries to drive water wheels and mills for various agricultural and industrial uses. Since the late 19th century, it has also been widely used for electricity generation. There are three main hydro-electric energy technologies:

  1. Storage systems – water is stored in a dam or reservoir and released to allow falling or flowing water to drive turbines and generate electricity.
  2. Pumped storage systems – excess electricity generated by storage systems is used to pump water to a higher storage point so it is available for electricity generation at a later time.
  3. Run-of-river systems – the natural and consistent flow of rivers is used to produce electricity. These systems typically have a lower environmental impact than dammed systems.

Large-scale hydro-electric facilities typically use storage or pumped storage systems. Small-scale hydro-electric facilities more commonly use run-of-river systems which require less water.

Hydro-electricity is capable of rapidly providing power on demand. It is the most established renewable energy technology in NSW. Production varies depending on annual rainfall and water availability, and large storage systems may have significant local environmental impacts.

Are there hydro resources in NSW?

NSW has generated hydro-electricity for more than 75 years. In addition to the existing large- and small-scale power stations, our extensive river systems have good potential for the development of additional small-scale hydro-electric facilities. Mountain ranges in the eastern parts of the state provide regions of high water flow due to abundant rainfall and steep slopes for water to travel down. Many smaller river systems have excellent potential for small-scale run-of-river hydro-electric systems, particularly those with existing infrastructure such as small dams or weirs. Water or sewage treatment plants and water supply pipelines also have excellent potential for small-scale hydro systems.Tumut 3 Power Station

Tumut 3 Power Station, the largest in the Snowy Mountains Hydro-electric Scheme. Photo courtesy of Snowy Hydro Limited.

How is hydro energy used in NSW?

Currently, there are 36 operating hydro-electric power facilities in NSW. The Snowy Mountains Hydro-electric Scheme, constructed between 1949 and 1974, is the largest hydro scheme in Australia. It has a 4200 MW capacity and accounted for 4.5% of total electricity generated in NSW in 2015. Small-scale hydro-electric generation accounted for 0.9% of total electricity generated in NSW (including ACT) in 2015. It has recently become more popular and cost-competitive than large-scale hydro due to lower construction and maintenance costs, as well as lower environmental impacts and water requirements. Small-scale hydro-electric facilities have been installed in wastewater treatment plants and water transfer pipelines across the state.

What is the future of hydro energy in NSW?

Most potential sites for large-scale hydro-electric energy have either been developed or excluded based on environmental or social factors. However, as technology improves, existing hydro-electric power stations may be updated or refurbished to increase efficiency and reduce environmental impacts.

The development of small-scale hydro-electric energy facilities, particularly using run-of-river technologies, and upgrading of existing facilities will be extremely important for future growth in the hydro industry.



the amount of energy generated for any length of time. This map indicates capacity as a megawatt (MW).


the ability to do ‘work’ or to ‘make something happen’. It can exist in different forms, such as thermal (heat), kinetic, electrical, chemical and potential (stored). Energy is measured in joules (J).

direct employment

fulltime equivalent of employment hours (FTE)

megawatt (MW)

one MW = one million (1 000 000) watts


the movement of electricity along transmission lines once it leaves the power station


a measure of the flow rate of electricity, equivalent to one joule of energy per second. One joule is the internationally recognised unit for measuring energy of all types.

For further information
Geological Survey of New South Wales
+61 (0)2 4931 6666
+61 (0)2 4931 6700
PO Box 344, Hunter Region Mail Centre NSW 2310
Geoscience Information Map