Monster power station load sets Northland record

The 130-tonne vaporiser, a key part of the geothermal power plant under construction at Ngāwhā, arrives on site just after daybreak. Photo / Tom Zink

The largest single part of a geothermal power plant being built near Kaikohe has arrived on site after a six-hour trip from Northport near Whangārei.

The 130-tonne, 21.5-metre-long vaporiser was transported on a 144-wheel trailer pulled and pushed by three heavy-haulage trucks, arriving just before dawn on January 15.

The vaporiser dwarfs even the three heat-exchangers, each of which weighed 90 tonnes, which have been transported to the power station site over the past month. It also sets a new record for the heaviest object transported on Northland roads in recent times.

The vaporiser's dawn arrival causes a traffic jam on Ngāwhā Springs Rd. Photo / Tom Zink

The Top Energy plant is expected to produce 32MW of power once fully operational later this year. The company's existing Ngāwhā geothermal power station produces 25MW.

A Top Energy spokeswoman said the three heat exchangers would be used to transfer heat from the geothermal fluid to liquid pentane. The hot geothermal fluid is extracted from wells drilled into New Zealand's second biggest geothermal field.

The pre-heated pentane would then enter the vaporiser where it would turn into a high-pressure gas used to drive the turbines and generate electricity.

About 150 people are on site assembling the power station, building a pipeline for geothermal fluid, and erecting power transmission equipment.

While the vaporiser is the biggest object shifted on Northland roads in recent times, it is not the region's biggest ever load.

Even heavier loads, up to 742 tonnes, were transported when the Marsden Pt oil refinery was expanded in the 1980s. Photo / supplied

Garth Wilson was a driver for Dale's Heavy Haulage in 1982 when the expansion of Marsden Pt oil refinery was under way.

The biggest loads he ever carried were refining reactors ranging from about 580 tonnes to a whopping 742 tonnes.

The parts arrived by heavy-lift ship at Marsden Pt, where a special loading ramp had to be built next to the wharf.

Barges and a gantry crane were used to get them off the ship and onto massive trailers for the short road trip to the refinery site.