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Wednesday, 22 June 2011

Direct geothermal energy could be key to our clean energy future

The Conversion
June 22, 2011

While direct geothermal energy is extensively used in other countries, it is rarely encountered in Australia.

This might be because we have cheap sources of energy (although, regrettably, not the cleanest). We also haven’t had to worry too much about alternatives yet.

Our climate is also less demanding than the much colder, heavily populated areas of the northern hemisphere.

But it’s highly likely that this is going to change dramatically soon. A carbon price will push up the price of conventional power and greenhouse gas emissions will have to be seriously reduced.

Clean energy has to come to the rescue.

While all forms of renewable energy will play a part, the geothermal alternative must become a major player. It is abundant, totally renewable (it is recharged over enormous areas by the sun), it involves well established and reliable technology, and, unlike most others, it is available 24/7.

Energy use in buildings accounts for 26% of Australia’s greenhouse gas emissions. Heating and cooling accounts for over half of this.

Cheaper energy, lower emissions

The introduction of direct geothermal heating and cooling to Australia – even on a moderate scale – would have a significant impact on power requirements. There would be enormous economic and environmental benefits.

As virtually every building in Australia requires some form of heating or cooling, direct geothermal energy could influence every Australian and their carbon footprint.

For each kilowatt of electrical energy put into a direct geothermal system, about 4 kilowatts of energy is developed for the purposes of heating and cooling.

This means that outside of the capital costs of the installation, 75% of the power is free.

A significant amount of electrical power in Australia is generated with brown coal. Replacing 75% of this with a totally clean renewable energy source would reduce greenhouse gas emissions to as little as 25% of what occurs with current practice.

Clearly, this is a crude assessment of what is possible and other fuel sources are not taken into account.

But the figures do indicate some of the significant economic and environmental benefits that can be achieved directly and indirectly.


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