News

Utilising supercritical fluids, geothermal could play a crucial role for NZ’s carbon-zero energy future

Wairakei geothermal facilities, Taupo/ New Zealand (source: Contact Energy)
Alexander Richter 23 Sep 2019

Lots needs to be done for New Zealand reaching its carbon-zero target by 2035, but targeted funding now provided for research on supercritical fluids of deep geothermal resources could provide a game-changing momentum and a much greater role for geothermal energy.

Two articles from New Zealand caught our eyes today. One is an opinion piece on Stuff.co.nz on why “Geothermal energy (is) critical if New Zealand is to reach carbon zero by 2050”, and the other one in the New Zealand Herald asks if “Deep geothermal: is this NZ’s clean energy future.”

Last week, we reported on new research funding provided to GNS Science on research on tapping deep and hot geothermal resources.  As described by the project lead, Dr. Isabelle Chambefort, these “supercritical” fluids could essentially provide 10 times more energy than derived through conventional geothermal resources.

Today, around 43,000 GWh of electricity were generated by all power plants in New Zealand, with around 17.6% coming from geothermal power plants and a similar proportion form non-renewable sources. With the 100% renewable target by 2035 by the New Zealand government, geothermal could therefore play an important role in reaching those targets.

These supercritical fluids provide much higher temperatures above 374 centigrades and pressure points, providing much “higher heat-content and lower density and so have the potential to generate around 10 times more energy than conventional geothermal for the same amount of extracted fluid.”, so Dr. Chambefort.  A similar project in Iceland, the Iceland Deep Drilling Project is targeting a similar point. The challenges are mostly technical as both the equipment would have to endure the temperature, the materials used e.g. for the well, the valves to hold the pressure on the well head etc are all technical challenges that need to be overcome. … and the next step naturally is also what equipment on the surface could then generate electricity with that supercritical fluid/ steam.

With the experience of New Zealand’s geothermal laboratories and more than 60 years of operations, New Zealand could be well positioned to make a great leap forward in research on supercritical fluids and their utilisation.

The opinion article in Stuff.co.nz strengthens the narrative that this research could be a game changer for the role of geothermal energy in New Zealand and thereby play a critical role in the country reaching its carbon reduction goals.

With that research, a beginning is made and one hopes that it will translate into additional and a larger, if not dominant, role for geothermal energy in the country’s energy mix.

Here a great video on the history of geothermal in New Zealand from Eastland Generation:

Source: NZ Herald, Stuff.co.nz