Re: Geothermal energy

From: Jonathan Clarke (
Date: Thu May 30 2002 - 06:54:04 EDT

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    Hi Peter

    It is a while since I read up on geothrmal energy in NZ during a hydrothermal
    tour of the place, but I understand a lot of the problems have been due to
    domestic usage, rather than electricty generation. Also a lot of the early
    power stations were very inefficient users of the thermal waters. With good
    design, including things like condensation and reinjection of spent
    steam rather
    than allowing it to boil off, a lot of the problems encountered in the early
    power stations can be avoided. With approriate management geothermal power is
    renewable. While traditional geothermal power is limited to a few localities,
    it can be very important. Even with only a few installations currently in
    place, I have been told that the Philippines currently generates about 25% of
    its power this way. Someone might like to check this.


    pbrunt wrote:

    > Hi
    > I thought it worth responding to Glenn's and David's posts on the above this
    > exact point has happened in New Zealand where we used to have more than 200
    > geysers at Wairakei, Rotorua and a few other smaller geothermal fields and
    > now have less than seven. The ground at Wairakei is sinking at the rate of
    > 1mm each year and so many thousands of tonnes of steam are removed that a
    > neighbouring valley can no longer be called Wairakei Geyser Valley because
    > there are no geysers. it is a joke to call it a Thermal Valley.
    > At Ngawha in the far North of my country the thermal activity is
    > dramatically reducing as steam is removed for power generation using and
    > ORMAT Sytem. This closed system using isopentane is reducing the viability
    > of the springs and pools at Ngawha and costing people their livelihood.
    > NZ has sacrificed short-term energy gains for its long term natural wonders.
    > Other countries are following.
    > Even so, geothermal systems are used to generate electricity in Italy, NZ,
    > USA, Eastern Russia, Indonesia, Philippines and some S. American countries.
    > Invariably geothermal geologists report a stabilising of the groung and
    > activity by the removal of energy as steam. So now people can live and work
    > in previously dangerous areas.
    > Peter Brunt
    > As Glenn noted, geothermal energy is only potentially available in
    > relatively few areas. Iceland may be able to get much of its energy
    > needs from it, but not most other countries. Geothermal development
    > risks disrupting hot springs and geysers, thus disrupting tourist
    > revenue and unusual biological systems.

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