NZ deep geothermal resources could provide up to 10,000MW

Steam pipelines near Taupo, New Zealand (source: Commons/ Wikimedia)
Alexander Richter 30 May 2011

Currently geothermal resources from about 3,000 meters depth are utilized for electricity generation in New Zealand. Now scientists believe that going deeper could provide up to 10,000 MW capacity or all electricity demand of the country.

News following an event held in New Zealand last week talks about that “New Zealand scientists are planning to drill a geothermal borehole 4 km or more deep by 2014 to test the feasibility of extracting super hot geothermal fluids to generate electricity, said a statement released by GNS Science recently.

Researchers from the state-run geothermal and nuclear sciences institute, GNS Science, reckon the energy from the fluids below the Taupo volcanic zone in the central North Island could generate enough energy to meet the entire country’s electricity demand.

Scientists and researchers from New Zealand and 10 other nations gathered in the town of Taupo Wednesday to discuss proposals for the project, the statement said.

Conventional geothermal energy in New Zealand derived from boreholes up to 3 km deep, tapping fluids up to 300 degrees Celsius, said the statement.

However, scientists believed that by drilling to depths of about 5 km and tapping even hotter fluids, the energy output could increase dramatically.

Conventional geothermal technologies currently provided about 13 per cent of New Zealand’s total electricity generation from an installed capacity of about 730 megawatts.

“Scientists conservatively estimate that deep geothermal resources in the central North Island could provide 10,000 megawatts for over 100 years for New Zealand,” said GNS Science senior geothermal scientist Dr Greg Bignall, a convener of the Taupo workshop.

“This would satisfy all of New Zealand’s current electricity demand, which is generated from a capacity of 9,000 megawatts,” Bignall said.

“But to achieve this there are a number of engineering and scientific challenges to overcome as conventional technologies would be pushed beyond their limits to extract fluids from such depths. Currently there is no satisfactory way of handling geothermal fluids that are 400 degrees Celsius.” Ground-breaking science, innovation and engineering would be needed for successfully drilling into the deep, very hot environments.

The workshop in Taupo, called HADES: Hotter and Deeper Exploration Science, would help in build partnerships needed to achieve this, said the statement.”