Steam brings business

by Dan Hutchinson

A new factory in Taupō is using excess heat from geothermal electricity generation to help solve the problem of nitrogen overuse on farms.

Tnue co-founder and director Bruce Smith explains the inner workings of the factory at Rotokawa.
Photo / Dan Hutchinson

Tnue – Total Nutrient Use Efficiency – is based out at Rotokawa and opened its doors last week for Taupō Business Chamber members.

Co-founder and director Bruce Smith grew up on a large pastoral farm south of Te Awamutu, and has spent most of his working life in agronomy. He became fascinated by the fertiliser industry in new Zealand.

“I was really fascinated with the technologies around controlled release and slow release and what they could do.”

Slow-release fertilisers are common in intensive horticulture and sold over the counter at garden centres but not used in large scale agriculture.

“My colleague and I were looking and thinking, ‘well, what is the biggest problem in agriculture today? And clearly it was the overuse of nitrogen fertiliser.

“We had farmers at Canterbury being accused of stuffing up aquifers and all the rest, and of course there was all the media about dirty dairy. So, it wasn't a very good look.

“But the thought was, well, hey, how about taking some of this controlled release and this slow release technology that is used in these very small, intensive blocks and see if we can develop that technology for extensive farming systems, which takes up around about 90% of the agricultural land use.”

So, with the help of scientists and trials in New Zealand and abroad, they were able to come up with a way of coating urea on a large scale – which they called Smartfert. But it required a lot of heat, to get the product up to 90 degrees Celsius so the coating would stick.

“We worked very closely with Ballance Agri-Nutrients, actually they were the ones that seemed to listen to our Mad Hatter story, and they actually supported us in doing some work in the field ... and yes, it worked.”

When they looked at manufacturing on a large scale, Bruce said they had to consider three things. First, they needed a product suited to New Zealand conditions, and able to be used across a range of different regional conditions.

Tnue production manager Joanne Thomson checks on the machinery that converts excess heat from a nearby geothermal power station into hot air that is used in processing the fertiliser.
Photo / Dan Hutchinson

Second, it had to be profitable for farmers. The slow-release nature of the product meant urea only needed to be applied once during the growth cycle of grass, rather than three times, which not only saved on the amount of urea being applied but avoided waste and associated leaching from applying more urea than the plant could absorb.

Third, they needed somewhere to put the factory.

“That is a big deal, because first of all, where the hang are you going to put it? And we figured that we used a lot of energy.”

Contact Energy commercial development manager Craig Stephenson suggested they use some of the secondary heat from its nearby geothermal power station.

“But, you know, that seemed a little bit hard. But he said, let's go around and have a chat to Greg Stebbing (Tūwharetoa Settlement Trust commercial advisor).”

Fiona Miller – geothermal cluster lead at business development agency Amplify – also got involved “working behind the scenes” and Taupō mayor David Trewavas.

“And then they said, ‘oh, well, why don't we all get together and have a nice big lunch?’ Thanks to David, and he did a real good sell-story on us, and that sealed it. And that was the beginning of why we came here.”

The Government’s green investment bank invested $2.5m to help get the project underway and with a lot of further investment and support, the factory opened in mid-2013.

The product and processes have been refined since then and the next stage of development will see bulk silos installed so trucks can roll up to the factory 24-7.

In the meantime, everything is tracked and monitored so they know where the bulk bags have gone and feedback from farmers has been used to further refine the product.

Bruce says the heat transfer system was expensive to install but the low ongoing cost made it worthwhile and it meant the factory also had very low carbon emissions, to go with the environmental benefits of reduced nitrogen use.

Tnue head of sales Dan Griffin said they wanted to partner with farmers to help them meet the demands of their customers and Government regulations.

“What is it that Mars, Nestle want? It's their consumers that are demanding that the food we produce is done more sustainably. So how do you prove that along the way?”

Bruce says the next stage of expansion will be about a year or two away and being able to build from scratch on a greenfields site had been a huge advantage when it came to future-proofing the business.