New Zealand to double well depths

In New Zealand, scientists intend to look deeper than ever for heat. Currently, steam from existing hot aquifers drawn from as deep as 3.5km powers seven electricity stations in the country, six of them in the Taupo Volcanic Zone, generating about 640MW a year, or 10% of the country’s electricity. They are now on a four-year project to drill as deep as 7km in the same region, called the country’s main geothermal hot-bed, looking for even hotter aquifers. Project leader Greg Bignall of GNS Science said there could be the equivalent of up to 10,000MW of electricity, every year for 100 years, in fissures deeper and hotter than those currently tapped. Their goal is to expand geothermal energy use to 20 per cent of New Zealand’s electricity needs. Mr Bignall adds that rock deeper than 8km in the zone will be too soft for drilling.