Tuesday, July 24, 2007

EROP: Geothermal Power Generation

A geothermal power station, as we know it, is one that uses the heat of the Earth to generate power. The heat turns water to steam, which in turn can be used to run a steam turbine that generates electricity.

New Zealand is particularly fortunate in that, because of its volcanic activity, it has numerous locations where the heat of the Earth can be tapped. The Ministry of Economic Development has estimated that geothermal power could supply 75% of New Zealand’s peak demand although only about 15% of that maximum potential has been developed.

I say fortunate because geothermal power is one of the most environmentaly friendly forms of power generation according to Murdoch University ...

  • Its abundant, secure, and, if properly used, renewable.
  • Using modern techniques, it emits less than 0.2% of the CO2 of the cleanest fossil fuel plant, less than 1% of the sulphur dioxide and less than 0.1% of the
  • particulates.
  • It does not add to environmental problems such as acid rain, mine spoils, open pits, oil spills, radioactive waste disposal or the damming of rivers.
  • Its reliable, reasonably available, high capacity, designed to run 24 hours a day and independent of the weather or fuel delivery.
  • Its modular design is highly flexible, expandable and construction does not have a high initial capital outlay & long lead time.
  • The fuel supply is indigenous (ie not imported), providing economic security, reducing imports and improving the balance of payments.
  • Because of its nature it can be stored.
  • It takes up little land.

Prince Piero Ginori Conti invented the first geothermal power plant in 1904, at the Larderello dry steam field in Italy and, on November 15 1958, New Zealand opened the second geothermal power station at Wairakei.

Australia does not have the same geologic make-up as New Zealand so that the possibilities for geothermal power are very limited. Small-scale geothermal power stations are possible, however, such as the one currently servicing Birdsville in Queensland, and South Australia is investigating the technology.

The Geothermal Education Office has some great general resources, including an excellent on-line presentation that is comprehensive and in-depth. For more on New Zealand's geothermal power industry:

This is a hyperlinked copy of an article I submitted to the Engineering section of issue 6 of ScuttleButt, the newsletter of the USS Southern Cross. For a free download of the newsletter, goto the Newsletter page of the USS Southern Cross web site.

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