Technology that allows coal ban a first for NZ dairy

Technology that allows coal ban a first for NZ dairy

Auckland, July 4
The engineers who were part of the ground-breaking decision to use electricity to power a dairy company’s major heat source say the decision showed courage and commitment.

In a first for Australasia, Synlait Milk is using an electrode boiler at its expanding plant at Dunsandel, south of Christchurch, choosing it over more traditional options including gas, diesel and biomass. Synlait had already rejected the use of coal on environmental grounds.

Babbage Consultants, the engineers who worked with Synlait to make the vision a reality, said electricity was the best option once the carbon footprint of the project was taken into account, and the electrode boilers they recommended were between 99.5 per cent and 99.9 per cent efficient.

“When we first looked at the options, we didn’t consider electricity because no one thought it would be viable for a boiler this size,” Babbage engineer Vaughan Blok said.

“We knew about the technology but it hadn’t been used for boilers in New Zealand. However, electrode boilers are used extensively in Europe, North America and South Africa, and the technology has been developed for decades.

“For Synlait to go for this option in a sector as huge as the dairy industry shows real courage and commitment.”

Synlait announced the decision as part of a raft of measures to cut its environmental impact over the next decade.

The commitments, revealed at the company’s annual conference in Christchurch on its 10th anniversary, include reducing greenhouse emissions, slashing water consumption, reducing nitrogen loss on farms and significantly boosting support for best-practice dairy farming.

In announcing the electrode boiler, supplied by Energy Plant Solutions and due to be commissioned in January, Synlait Chief Executive and Managing Director John Penno committed the company to never building another coal-fired boiler.

“We’re stepping up to take responsibility for our business and demonstrate leadership in the primary industry that will benefit all New Zealanders,” he said.

Babbage engineer Vaughan Blok said the key to the technology was simple physics, with the boilers using elecrodes, not electric elements like those found in domestic water heaters.

“In these boilers, electrodes are submerged in the water, which vaporises into steam,” he said.

“It means you only heat what you need and you don’t have tanks of hot water, which is a waste of energy.

“The boilers are easy to manage, they can heat from cold in less than five minutes, they can heat from standby in about one minute, they can produce variable amounts of steam as required, and the electrodes don’t wear out.

“And the entire system is so compact it comes in just two shipping containers.
“When we analysed it, it was an obvious choice.”

But having made the decision to go electric, the next steps were designing the infrastructure and ensuring the equipment met New Zealand technical requirements. Babbage has provided project-management and engineering services to Synlait for 11 years and knew what the innovative dairy company required.

Another key element was getting an improved electricity supply to the plant that would meet the new boiler’s needs.

“Orion Energy had to move fast to upgrade its network to meet the demands of this project,” said Blok, who is the industrial electrical team leader at Babbage.

“In technology terms, this is not especially complex – in fact it turns out to be quite simple.”

Fact box
• What is it: Electrode boilers have large electrodes suspended in a pressure chamber and immersed in water. The electrodes instantly turn the water into steam.
• How big is it: Electrode boilers can be as big as 100mw, but this one is much smaller
• What are the alternatives: Biomass, diesel, gas (LPG) and coal. Coal was rejected by Synlait on environmental grounds.
• Why choose electricity: Because of the overall cost benefits including capital cost, running cost and the carbon footprint.
• What’s the philosophy: It meets Synlait’s goal of being the most environmentally friendly dairy company in New Zealand.

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