Superhot geothermal

Duration: 3:58

[Opening scene of geothermal steam across a rural landscape]

Mana Newton (Chair, Tauhara North No.2 Trust, land owner): Our ancestor, his name was Tahumatua, and he landed on our shores around about 1250 AD.

[Mana Newton speaking against a backdrop of patterned glass with Māori motifs]

He came from a hot area or warm place. He was looking for that heat that he had come from. His descendants have lived there ever since then. And so for us, it's always been a tongue or a treasure as part of who we are as a people.

[Title frame: Words ‘GeoShot NZ’ appear above a geothermal lake]

[Scientist in her laboratory]

Dr Isabelle Chambefort, GeoShot NZ science lead, Earth Sciences NZ: This project is the most exciting thing that has been happening to New Zealand for a long time, at least 50 years.

[Aerial views above steaming and erupting geothermal features]

We are testing if we can have energy that is coming from the heat that is generated by our land.

[Animated infographic of a stylised cross-section of the Earth’s crust with two geothermal stations side by side on the top. One drills to conventional depths of 2-3 kms deep, the other to ‘supercritical depths’ of 4-6 kms. Wording shows ‘supercritical’ temperature and pressure]

Hon. Tim Groser, Chair, GeoShot NZ Governance Group: When you go deeper, you get hotter. When you get hotter, you get more energy. But at a very specific point known as supercritical and it can be defined by a scientist very precisely – 374 degrees Celsius at 220 bars.

[Tim Groser seated in an office looking out over buildings and Wellington harbour]

You get a bigger bang for your buck much bigger – maybe three times as much energy out of it and it's essentially unlimited.

[Geothermal landscape of steaming mud]

[Wind turbine against blue sky]

It's not an alternative to wind, solar and hydro.

[Watering flowing from hydro dam]

It is actually a natural complement because of the base load issue.

[Tim Groser close-up]

[Aerial footage of Rotokawa geothermal station]

The base load means keeping the machine running 24/7, 7 days a week, 365 days a year.

[Scientist in laboratory then cust to aerial view of geothermal power station]

Dr Chambefort: Because if we can deploy geothermal everywhere, you can also reduce drastically the fossil fuel use.

[Dr Keith Turner in hi-vis PPE in front of geothermal station]

Dr Keith Turner, GeoShot NZ Governance Group member: It's low emissions and you know, a lot of the fluids can be reinjected into the ground. So environmentally it's a very attractive proposition.

[Speaker in hi-vis PPE on elevated position by proposed drilling site next to Lake Rotokawa]

Robert Rankin, GeoShot NZ project director: So we're trying to drill to 4 to 5,000 m which is significantly further than we've ever gone before. We then were going to encounter very high pressures and temperatures which is going to challenge the equipment and integrity.

[Speaker in hi-vis PPE on elevated position by proposed well site next to Lake Rotokawa. Sweeps around farmland, trees and steaming geothermal features]

Dr Chambefort: We've chosen this site for this new exploration in New Zealand following decades of work to understand the geology.

[Drone footage of Dr Chambefort and Robert Rankin at proposed well site next to Lake Rotokawa with farmland, trees and steaming geothermal features]

Drone footage of Lake Rotokawa and close-up surrounds with geothermal steam rising from land and water]

There is probably a shallow intrusion. So a pocket of molten rock underneath the crust at that specific location underneath Rotokawa and this brings heat really close to the surface and that is why we're going first to drill in this site.

[Speaker sitting outdoors with backdrop of native plants and examples of drill bits beside him]

Ralph Winmill, Geoshot NZ Lead well designer, Geode Well Engineering: New Zealand has been doing this for a long long time. I was taught by the early pioneers in the geothermal industry. They've got New Zealand standards which is actually a rare document. So that's used internationally as the kind of substitute international code for doing it. I make it sound hard but and it is but we've learned how to deal with all these things but then going to supercritical is just that next level.

[Steaming vents of geothermal steam and bubbling water in natural landscape]

You're trying to wrestle something out of Mother Earth and she holds all the cards.

[Tim Groser close up, speaking in Wellington office]

Tim Groser: It is not a commercial project.

[Aerial footage of geothermal station and back to speaker in office]

What we're trying to do is to prove first of all the technology is up to this and secondly to be able to bring the fluids to the surface for our engineers and worldclass scientists to analyse. That is the central first step towards the commercialization of this.

[Speaker in front of geothermal station]

Dr Turner: We've got to learn a great deal and put that on the table for the commercial entities to follow. So government is absolutely fundamental to getting this started.

[Speaker at proposed drill site next to Lake Rotokawa]

Robert Rankin: Well, I think the foundation of any good project is partnerships and relationships.

[Drone footage of proposed well site next to Lake Rotokawa showing farmland, trees and geothermal features]

And if we can harness that effectively, we can really change the dynamics of energy to power the whole of New Zealand.

[Speaker close up with patterned glass in background]

Mana Newton: Our consideration is that irreversible damage of our reservoir is out of the question. We can't permanently damage Papatūānuku, Mother Earth, or the resources that we have.

[Aerial scenes of Lake Rotokawa and surrounds]

We are the reservoir, it looks after us, but it's our responsibility to also look after our reservoir.

[Closing music, thank-yous and partner logos]