A hydroelectric dam stores water and has a lot of potential energy. This water can be replaced quite easily through natural processes such as the water cycle or it can be pumped up to a reservoir and act like a water storage battery. Hydroelectricity works by using gravity, from forcing water from a high point through pipes to a turbine that is below the dam. The resultant discharge has little to no effect on releasing toxins into a waterway.
A diagram of a proposed pumped hydro dam in South Australia.
In Tasmania, the mountains throughout the state makes it suitable for large scale hydro dams, and already has 30 hydro schemes generating electricity. Throughout the rest of Australia, large scale hydro dams aren’t suitable due to being unaffordable to build, but smaller pumped hydro dams can be located throughout Australia.
Australia has numerous places where it can use ‘pumped hydro’ as a means to store electricity. The only problems with pumped hydro is how it is pumped back up to the higher reservoir. Currently in Queensland, a disused gold mine site is home to a large scale pumped hydro scheme. In conjunction with a 50-megawatt solar farm nearby, which could be utilised to pump the water back up to the higher reservoir, essentially, it can pump water back up to the higher reservoir without using any electricity from the grid on a sunny day. This is beneficial because it acts like an electricity storage battery, which stores the potential energy that can be generated on another day when the solar farm isn’t generating enough electricity or demand is high on the grid. These setups could be used when renewable electricity isn’t in high demand, especially when Governments around the world are changing to renewable sources of energy. It has a less harmful impact chemical battery storage, as it utilises water. However, this has impacts on ecosystems, as it could be flooding the first reservoir one day and the next, it could be causing a drought (Sucking up all the water).
In other cases, a small-scale hydro turbine in a stream or flowing river can easily generate electricity for any nearby buildings depending on the demand those buildings require. This is somewhat inexpensive as it requires only fast flowing water without any real catchment or containment area.
This has been done in Europe, with numerous pumped hydro dams scattered across the mountainous regions. Other nations like Ireland and Spain are also considering the use of pumped hydro, as it is very suitable with any size reservoir. Used in conjunction with solar farms or wind farm, these storage facilities could be utilised to offset using carbon based fuels or energy sources. In Australia, over 22000 sites could utilise this method of electricity storage and with excess renewable energy used to pump the water back in the higher reservoirs, the dependence on fossil fuels could be all but eliminated.
Hydroelectricity can be generated with low running costs, that cannot be averaged due to different capacities or sizes of dams that generate the electricity. Other factors like the number of turbines and construction costs may be factored into the end price, but can easily be maintained at a running cost similar or lower than that of solar or wind, making it cheap to use in Australia.
Hydroelectricity does have its benefits; however, it can be reliant on rainfall or access to water. One problem with hydroelectricity in Australia, is its unpredictable climate cycles such as the Southern Oscillation or the Indian Dipole effects. Both can cause either decreased rainfall or cause flooding, damaging infrastructure essential for the transportation of electricity or the plants themselves. Australia can also be subjected to extreme weather conditions such as cyclones, which could potentially damage pumped hydro stations and surrounding renewable electricity producers in the vicinity.
Tasmania also has the capacity to include numerous more pumped hydro dams or full-scale hydro dams, however, these dams can be challenged and prevented from happening, for example, the Franklin river hydro-scheme in 1983, which started in 1978 with a proposal by the hydro-electric commission in Tasmania. This high court battle signified that some areas of Australia may not be used for electricity generation and could be protected against clearing, mining, or other destructive activities to the environment or ecosystems already there. To get a better understanding, it is advisable to visit this page for more information on how this dam was denied approval. This results in the possibility of many planned hydro schemes or other renewable projects to be scrapped, due to being either located in a national park or recognised as a world heritage site.
Sites to explore for more information:
Image of pumped hydro sites and a video plus other information surrounding pumped hydro capabilities - http://www.abc.net.au/news/2017-09-21/pumped-hydro-renewable-energy-sites-australia-anu-research/8966530
Queensland is currently expanding one of its major pumped hydro dams. Located at the disused Kidston gold mine, this expansion seeks to increase the capacity of the dam so that the duration of the power it can generate is extended, which can run for longer and can help to fill in for the demand of electricity during its run time.
Tasmania has over thirty hydroelectric dams in operation, each with varying outputs that supply most of Tasmania with the energy it needs to sustain itself practically off renewables, but when the tides turn, can rely on other sources of renewable fossil fuels to fill in the gap.
Feel free to Explore Tasmania’s energy generation sources here: