Full Steam Ahead
- Written by
- Dyani Van Basten Batenburg
The latest from the underground
New Zealand’s foothold in geothermal energy spanning eight decades – we are deemed world class leaders, paving the way in innovative techniques, processes and engagement, and future-forward in our thinking. Our geothermal activity predominantly occurs due to high heat flow in the crust along the Pacific – Australian tectonic plate boundary. And, we have hot springs that span the length of New Zealand – top of the North to the bottom of the South – coupled with geothermal activity undersea – with the likes of the Kermadec-Tonga arc zone. A geothermal resource is not isolated to one entity. Deep heat sources i.e. magma, are influenced by regional climate, water interactions, pressurisation through submergence and earth processes happening in and around it, for example earthquakes or eruptions. In the central North Island alone – aptly the Taupo Volcanic Zone – there are over 20 geothermal systems – making us one of the richest and rarest places on earth for development.
With our knowledge growing substantially in geothermal resources since the 1940s – when drilling deeper underground kicked into action the question begs, “Where to from here?” Especially given the bounds of New Zealand’s hard and fast approach to climate change. How do we capitalise on the deliverables of this resource even more, whilst treading a low – or nil – carbon footprint, and abate sustainable concerns for its future?
We celebrate our roots, we dig a little deeper and tap into the value proposition of this natural power player, say geothermal experts.
Energy co-opetition
Of the 26 countries that produce geothermal energy, New Zealand is punching above it’s weight, with technology developed at our Kawerau and Wairakei power stations enabling others to advance the world over, explains Paul Siratovich, president of the New Zealand Geothermal Association and director of Upflow NZ, geothermal intelligence specialists.
“Our development of liquid geothermal reservoirs has afforded us a hand in developments across the globe. We’ve forged solutions to problems and helped others based off our knowledge. Iceland is the closest to us in terms of geothermal innovation and advancement – and we actually generate more geothermal energy than them, though they beat us out on geothermal megawatts per capita. We have a co-opetition type relationship with them – we co-operate with them and work alongside them, and compete with them – but its good-natured effort to decarbonize global energy sources.”
After all there’s nothing like a little energetic competition to keep us on our geothermal toes, says Paul.
“Iceland is essentially leading the charge in super critical geothermal territory – drilling super deep wells to access powerful fluid that carries more energy – and they’ve got 10 years to their name. It’s something we as scientists here in New Zealand have been closely plugged into, and are currently focussed on understanding and researching intently for own purposes,” he says.
Super sizing our geothermal tourism offerings is also something we stand to benefit from as a country – the gift of knowledge and power.
“Iceland does geothermal tourism very well – something we don’t have. For example, their Hellisheidi Geothermal Power Plant – the third largest in the world – is the state-of-the-art facility with a huge visitor’s centre and multimedia energy exhibition. We used to have a visitor’s centre at Wairakei years ago but that dissipated, so we don’t have that educational aspect behind our pursuits. Taupo being the ideal setting for a geothermal centre, Te Papa is just too far removed.”
Dig a little deeper
Taking our geothermal enterprising to the next level – like Iceland – is super important to the future of our industry. Currently, an GNS Science led MBIE research endeavour is analysing – and uncovering – the supercritical roots of our geothermal systems to extend and expend our energy reach (www.geothermalnextgeneration.com).
“These super deep wells essentially gift greater power output – but they are complicated by different characteristics, so the actuality of super critical coming to pass in New Zealand is still years down the track. We are very practised and careful in how we approach and research these possibilities, running numerical models, accessing deep well information, geophysical surveys, imaging and information coming from our fields we are generating now i.e chemistry and heat outputs,” says Isabelle Chambefort, GNS Science senior geothermal geoscientist.
Supercritical geothermal could be 20 years in the making here in Aotearoa, but when it does arrive it could provide New Zealand with 10 times more energy than conventional geothermal energy.
“Expansion into supercritical opens huge doors for the future of New Zealand’s geothermal landscape,” says Isabelle. “It’s less dense, carries more heat – think of it as a power fluid. Right now, we’re looking at the value proposition of supercritical geothermal for NZ– we can potentially supply entire cities across the country and look to exporting energy e.g. converted into hydrogen.”
The key aspect of geothermal energy and what it makes it such an exciting journey to be a part of – especially as we look to supercritical – is the sustainability behind it.
“We’re not going to run out of geothermal supply anytime time soon – New Zealand is one of the largest volcanic areas on earth. In terms of volume of magmatism, it’s as big as Yellowstone National Park in USA – there’s definitely some heat down there, it’s not going to turn off,” says Isabelle.
And, while any energy production is going to have risks attached to it, research GNS teams are conducting now is focussed on mitigating any potential super critical drilling risks.
“With any extraction process – across any industry – there’s risks, but with super critical we know how to drill to avoid magma, we know the scale we need to work to and how utilise this energy conversion technology. We’re not going to drill into magma or cause explosions or loss of control.”
The carbon question
As for geothermal energy and carbon emissions, there’s much misconception around quantity and where emissions are coming from, says Isabelle.
“Some carbon emissions are produced from the geothermal power stations – but there is always going to be a certain amount of naturally occurring carbon dioxide attached to them – it’s a volcano we can’t stop that,” she says. “We have the competitive advantage in transitioning the New Zealand energy sector and economy with geothermal and part of this – alongside supercritical possibilities – is a focus on decarbonising our electricity and process heat sectors. We’re aiming for zero emissions at the power station – and there’s many ways we can achieve this.”
One of achieving zero carbon emissions at the plant is capturing it and injecting it back into the reservoir from where it came.
“It’s called carbon capturing,” explains Paul. “We can also pull carbon directly out of the air and use that excess heat to put carbon directly back underground. There are many emission research projects happening countrywide that are focused on helping geothermal power installations become carbon negative.”
What we do need to remember in the quest for a climate revolution is nature’s hand, says Paul.
“Look at Rotorua, Taupo and the natural emissions profile from places like Waiotapu, Waimangu Valley, Tongariro – they’ve got nothing to do with human process. Monitoring from GNS showcases that what’s done from a geothermal energy perspective is a minor contribution of the carbon dioxide emitted in the natural background.”
The value stakes
Not only does supercritical open up new possibilities for investment, it supports economic development and the extension of geothermal resources for material processing, industrial scale forestry, dairy and other industries.
Taking advantage of geothermal heating isn’t something new for businesses across the Waikato and Bay of Plenty regions – many, like Miraka (milk production), Natures Flame and Tenon (wood products) have been tapping into geothermal heat delivery for some time – but we need to extend its reach.
“At the moment it’s an economics question: How far do you want to run a pipeline of hot water?” says Paul. “I’d say businesses within five kilometres of a geothermal power station stand to benefit the most from geothermal heating – beyond that the economics have to be really favourable.”
“In places like Rotorua where there is no central geothermal heating infrastructure – but should be given their geothermal position – super critical production will allow us to change that,” says Isabelle.
For businesses like Arataki Honey in Rotorua, geothermal energy has been their go to for 60 years – an investment that keeps on giving.
“We looked for land that had geothermal steam available when we first started out, and although the costs were significant, we have benefited hugely across the board,” says Russell Berry, director of Arataki Honey, Rotorua.
Holding a one third market share in New Zealand’s honey consumption, Arataki’s success has been built on good business practise, long-term vision and sound decision making – with a sustained heat source at the centre.
“We get some hard frosts here, so it’s important to have a consistent heating supply. We have our own bore – which we drill out every year to get rid of the silica build up, and there is a corrosion that occurs in the pipes (but that’s part of the package), it’s the logical choice for us.”
Beyond just heat for honey production, geothermal has proven its worth business wide.
“All our buildings are heated by geo, even our under-floor heating in the visitors waiting room – we pump it around all sorts of places. Because it’s a controlled water supply and heat system we can ensure we get maximum use from it. It even supplies our Waiotapu Tavern next door with all their heating – including heating the hot water for the whole tavern.”
And, although Arataki’s sister operation in Hawke’s Bay is solar powered, Russell says there’s no temptation to step into the sun.
“We don’t get as many sunlight hours as they do over there – but it seems to work for them. For us, geothermal is a forever project. And, it helps to have engineer minded people on your team, so you’re not having to pay for external guys to come and fix a steam leak or adjust your taps.”
And as for the expert’s speak on solar and wind within a geothermal vision? They still have a role to play – just not a dominant one.
“Solar and wind are getting cheaper and cheaper to install but they’ll never replace carbon-based fuels on their own. They’re intermittent – the high-capacity factor, base load energy isn’t there. They’re a complementary resource,” says Paul.
Isabelle agrees. “Science isn’t very good at communicating the value chain of geothermal. And I think generally there’s this unspoken ideology that solar is best by the climate – but in fact there’s more carbon produced in the manufacturing of solar technologies than there are emissions from geothermal energy production. Our solar panels are all produced in China – where most of our mined minerals come from – and there are a lot of rare metals that go into solar and wind. We don’t mine for these in New Zealand, so we have to import them,” she explains. “It’s a case of us turning a blind eye to these high emissions produced in China, a not-in-my-backyard-mentality, that creates this false belief system that we are playing our sustainable part. But are they the best solution for Aotearoa New Zealand while we have such a natural gift heat resource?”