Everyone has seen it - the awesome power in the torrents of a waterfall or even just in a downhill river. Beyond the spectacle are important energies at work, ones that could help us secure a sustainable future if properly harnessed.
What is hydroelectricity?
Hydroelectricity means producing electricity by making the most of the gravitational forces acting on water. Sounds complicated? It’s actually not. Hydroelectricity simply involves using flowing water to push turbines around which, in turn, generates electricity. Its name is derived from the Greek word for water – hudor.
How hydroelectricity energy works
The most well-known way of capturing hydroelectricity is to build dams across rivers, trapping the water and storing it up as potential energy for future use. Some of the most famous dams in the world, including the Hoover dam in the USA, were built with this in mind. On release, the water runs over turbines which generate enormous volumes of electricity as they spin. The biggest hydroelectric dam in the world, the Three Gorges Dam on the Yangtze River in China, has an installed capacity of 20,300MW.
Advantages of hydroelectricity
There are two major advantages of hydroelectric projects. First of all, they are predictable – companies and governments will have energy stored up in the form of huge volumes of water in a dam. Secondly, they allow massive energy release at very short notice, making them perfect for industry. Well-built dams can last for many years, although require lots of maintenance.
Disadvantages of wave energy
Building dams is often prohibitively expensive and they require almost constant maintenance and monitoring due to the constant stresses and strains of running water. Many countries do not have the mountain rivers required to build such structures and those that do often run into difficulties as they flow across borders with countries. Dams can also damage the environment as it means blocking off rivers on the one hand and flooding valleys on the other.
Hydroelectricity around the world
Whilst hydroelectricity was the great renewable project of the 20th century, many developed countries have been reluctant to introduce new building projects. China, Brazil and India top tables of countries planning new projects in the future. In India such plans have been a source of great controversy. It is no coincidence these three nations are among those predicted to become global economic leaders over the coming decades. The dams will be able to provide energy for the unprecedented industrialisation which will take place in those countries to continue at pace.
Hydroelectricity in Australia
Australia does not have a long history of hydroelectric energy; it’s lack of large rivers and relatively flat landscape have not lent themselves to such schemes. However, some small, localised projects have been developed recently in Tasmania and in the Snowy Mountains. In spite of these successes, small-scale hydro will always be the name of the game in Oz.
Hydroelectricity is quite possibly the most widely used, and highly valued, renewable energy source in the world. Large-scale hydro is now somewhat out of fashion. It is unlikely such developments will be seen for some years in Western countries. On the other hand, the developing world has embraced such projects; these countries are among the leading exponents of hydroelectricity.
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