The last of its kind - Waikato’s cathedral to power

Friday, 26 May 2023

As the Waikato expressway skirts the edge of the Kimihia Wetland and begins traversing the long straight beside the river north, you have beneath, beside and above you the region’s rich coal history.

In the rearview mirror, like lit cigarettes, the tawny tipped chimneys of the Huntly Power Station will fold into the Hakarimata Hills. Beneath the asphalt are coal seams 30-35 million years old and if you’re travelling at dusk, the street lamps lining the road might flick on too.

Those, you can be reasonably sure, will be powered thanks to Huntly.

In the Waikato you can chart with a single gaze the history of the black rock that has kept the country’s lights on, provided jobs and warmed the planet.

The most obvious symbol of this history is the power station. From what used to be State Highway 1, a few cursory information boards and the obscuring canopies of trees on the adjacent bank belie the scale and importance of Waikato’s electric edifice.

Turning 40 this year and opened in 1983 with a nameplate capacity of 1000 megawatts, “the plant”, as it’s referred to by those who work within it, is fuelled by a blend of local and Indonesian coal, gas from south Taranaki’s Kupe field, and recently, Canadian wood pellets, pressed and processed to resemble the thermal efficiency of coal, albeit without the emissions.

It is the last of its kind in the country.

Yes it still burns coal. No, it isn’t out of action.

The workers

From the now sparsely populated car park in which the hundred or so workers who still ply the plant leave their vehicles, it’s hard not be struck by the inclusion of float glass, corrugate and shrubbery that furnishes the power station with a campus like quality.

Three of those cars belong to Te Iwi Morgan and Gareth Dodd and Scott Westbury.

The three men all have heavily specialised jobs at the plant: part art, many parts science.

The trio have almost half a century’s experience between them, and for Morgan and Dodd the power station has always been part of the scenery.

Morgan grew up in the town of about 5000, and with 2% of the town's population working at the power station, a role at the plant beckoned.

From being “on the broom” to leading a team of 11 fitters, Morgan’s story is not an atypical one at the power station.

As well as generating close to 1000 megawatts of power at full capacity, the plant is also a reliable employer in a part of the country where opportunity can be hard to come by.

Grinning, Morgan tells of first coming in as a general hand while on a university break.

“Fortunately enough, I did the general hand for five years for a contractor. I had the opportunity to work alongside mechanical fitters, when I did that, I let my hands do the talking and that’s got me to where I am now.”

Last year, he was made a maintenance programme manager. From sweeping the floor to managing it. Huntly can do that for you.

Unlike Morgan, Dodd’s family have a history in coal.

Dodd’s father was a coal miner at Rotowaro and after that Puketirini, Huntly West and finally East – a CV that tells the story of the region’s coal history in and of itself.

Dodd sees his role as the plant’s maintenance manager as “a privilege”. It’s provided stable employment for him and his family since he left school.

Huntly’s function, he says, hasn’t all changed all that much in the 23-years he’s been there either.

“What is does for the national electricity supply and the security of supply is probably just as important now as it was back then. When we run now we are always running for a very good reason.”

Increasingly, that reason is to provide a stable “back-stop” of power during dry years, or with the erection of wind farms, when the wind isn’t blowing.

The control room

Those reasons are best witnessed from the control room.

Here is where the electrical demand of the upper North Island is met.

Connected to the turbine hall via a sky-way and perched upon dozens of concrete stilts, the imprint of the timber armature still visible, the control room which is staffed 24/7 commands views across the plant’s substation, the engorged river and through to the stubbled hills beyond.

This is an electric landscape.

Behind glass curtain sliders are four desks.

Each occupied desk represents a turbine and boiler set that is on, and powering lights and computers nation-wide.

On the screen in front of 33-year veteran of the plant Sandy, who gives only his first name, screeds of information about temperatures, coal feed rates, pressure and power output are displayed in pixel form.

In the hour or so we are in the control room, 4.3 tonnes of coal flows into the furnaces helped along by 13.8 tonnes of gas piped under pressure directly from Taranaki.

On another, a direct view into the furnace via a flameproof camera.

Flames incandescent white. Temperature: 453C.

Dodd explains that the plant isn’t running at full capacity all the time.

“It’s a very versatile plant. It fulfils a lot of requirements that are always hard to plan for.”

Every half-an-hour, the Electricity Authority (the agency that administrates the nation’s electricity market) signals how much capacity will be needed. It’s then the job of the control room to respond.

Turbines are ramped up or down in anticipation of heavy power usage periods, Dodd says pointing to the day’s expected demand charts.

Kiwis turning their tellies on or making a cuppa all have an effect Dodd says, and that effect is noticed here at Huntly.

Evening “plug in” and morning breakfast making periods are more pronounced, he says, and so the plant must be agile, ready to ‘burn and turn’ in order to keep kettles boiling and phones charged.

The control room is at the pointy end of the economics of supply and demand.

The plant

Huntly has forty years of New Zealand’s economic history shoe horned into a single building, with room to spare, explains Dodd.

The plant was designed with the worker in mind.

At the time of construction, the plant was and remains one of the nation’s “halls of industrial development”, says Dr Jo Whittle who wrote her PhD thesis on power generation.

“They were so modern for their time. Engineers were proud of them, and they definitely had a magnificence in the scope of what they were. They meant something.”

It shows.

Its exterior conceals its cavernous, almost cathedral like interior providing ample space for “lay-outs” and fixes.

Its fastidious symmetry and angular verticality makes the facility look serrated from afar.

Inside, latticed steel work supports a thin tin roof, 40 tonne gantries soar overhead like church buttresses and sunlight diffused through lead light windows imparts a less pallor than glow through the turbine hall.

Inside the hall it’s near silent.

This is a cathedral. A cathedral to power.

Whittle explains this aesthetic sensibility is no accident, these sites were “built by the government for New Zealand,” at a time when symbols were held in the same esteem as deeds well done.

“The architecture inside and out, as much as possible, reflected that. It did change over time, because by the time you got to the 60s and 70s you got, perhaps, a little more economy.”

Those trees that impede the view of nosy motorists on the opposite bank serve a purpose, Whittle explains.

“There’s an enormous amount of pride, and pride in some of the landscape design around the plant. They were proud of what they were doing to try to integrate something very enormous and very industrial… So they weren’t really people coming in to say “we don’t care about you or what this place looks like. They actually wanted to make this something for New Zealand, and they did care about the aesthetics.”

Good things, after all, take time. The now full canopies of the trees that conceal the turbine hall were planted in the hope that as the plant grew old, their leaves too would grow to become part of the landscape and imbue the site with an abiding sense of dignity.

The day that Stuff visited, number four Rankine turbine was undergoing a scheduled maintenance survey. Conducted every eight years, the process of lifting lubing and luffing the turbine back into place is also as rare as witnessing a solar eclipse.

Construction by the Ministry of Works started on the concrete and steel complex in 1973 and continued until its opening a decade later.

Dodd recalls seeing pictures of the plant at a colleague’s house in which the first Rankine unit is generating while the rest of the building’s shell is erected next to it, it was all go from day dot.

“It’s never the right thing to do [build the plant], but once you’ve done it the value that it presents later on is immense,” Dodd says.

The Rankine process is, in essence, a large kettle powering a fan, spinning a generator. Water is heated to become supercharged, high-pressure steam exceeding 400C. The scorchingly hot energy that is best quantified by the number of homes it can power, is forced at almost 130 atmospheres of pressure into precision-milled Parsons turbines, spinning generators.

Tolerances are so fine that sometimes the plant’s fitters and turners have to resort to hand planing metal from castings to fit components together, Dodd says.

Ultimately, it’s heat, fuel and oxygen that runs the place.

While Parsons of Newcastle upon Tyne in England’s north-east has been lost to mergers and deindustrialisation, the energy supply of much of the North Island still depends on the steel smelted a world away.

Dodd explains that six turbines have been housed on the site at one time or another. Initially four Rankine units were in place at the plant and have since been joined by another steam turbine and a combined cycle gas turbine.

The combined cycle gas turbine built in Japan by Mitsubishi Heavy Industries is Dodd’s favourite, visiting the factory in which it was made in 2007 was like “visiting Mecca, you could say that, yeah!”

”It’s so hot in there, 1400C, that without the cooling air blown through tiny holes on the turbine blades, the thing would melt itself.”

Built in Huntly to take advantage of ample reserves of coal and river water and proximity to large electricity markets in Auckland and Hamilton, the Rankine units of the plant are powered by steam, super heated by several enormous Canadian-made boilers fired by coal, gas or sometimes a mixture of both.

At a time when imports were tariffed, the burgeoning gas and coal fields of Taranaki and Huntly respectively, provided ample and convenient fuel to the plant.

The trio tell that because of mismatches between old imperial fittings and new metric ones, clever work-arounds have been dreamt up. Working on the plant floor, Dodd points out four guys hunched over a housing component off unit four.

“They’re all Huntly, those guys. That tool they’re using it was invented by a guy while working in the plant.”

The tool, he explains, mills a very fine layer of steel off the inside of the housing’s seal. Over time, heat expansion can put out micron fine tolerance on seals and fittings, this machine puts them right.

With equipment that old, you might think Huntly is on its last legs. If that’s that case, the plant certainly hasn’t received the message.

“The plant has always had a good investment strategy. The reliability of the plant has kept up, we can really take advantage of that past 40 years of good investment, good maintenance and good operating everything within spec and operation limits,” says Dodd.

Westbury, who is the plant’s general manager of generation, says that due to a rigorous preventative maintenance plan and the toil of guys like Morgan and Dodd the plant will run comfortably until 2030, and perhaps even beyond with a few modifications.

The History

For over 140 years, coal has been hewn from the primordial rock underneath the Huntly area.

Until the early nineties, the coal fields of the mid-Waikato were the country’s most important; heating boilers in dairy factories, steel mills, and power stations across the country. Nationwide there were 45 mines, today, only 15 remain.

Everywhere you go in the town a sense of history, sometimes geological, strikes you.

From the rocks themselves that date to the Oligocene, to the buildings that populate the sprawling plant site, rendered in concrete to get past stringent ‘70s import requirement intended to boost the amount of local material used in construction.

History is literally being dug out of the earth here.

Whittle's PhD thesis dedicates a chapter to the environmental and social opposition towards the plant’s construction. Huntly, it turns out, was the first proposed industrial site that the public could make submissions on to the erstwhile Town and Country Planning board, in a process not unlike today’s resource consents hearings.

She explains that, in the popular imagination of the time, Huntly was not seen as scenic nor particularly well off and hence a good site for employment and large scale public works.

This ambivalence as to its potential location and the impacts upon it, in part rendered local support towards its construction.

“There was local support originally because the area had become quite run down, a lot of the population had left with the coal mines closing down, so there was that feeling of revitalisation, a use for the coal, but at the same time there’s also the fact that it wasn’t an area considered beautiful. There wasn’t a scenery component.”

Nationally, there was no great outcry about the proposed site either.

“People weren’t that bothered by the location because they considered it just farming and just a mining town. There wasn’t a national reaction to it like there was to hydroelectric development around the country a few years prior.”

In her thesis, Whittle uses the language of the “technological sublime” to describe Huntly. The sublime sees people feel a sense of near-spiritual awe towards technological marvels.

Interestingly, the sense of doting people impart on these spectacles, like Huntly, quickly becomes annexed as they are integrated as “sights” in the lexicons of day-to-day life. For many Kiwi families, Whittle says, Huntly is a “milestone”.

You know where you are in relation to everything else in North Island when those chimneys appear.

In Huntly’s case though, the locals also had a sense of foreboding.

A familiarity with coal-powered schemes, like that at Meremere, meant locals were aware of the disappointing feeling of the expectations of a technology not matching reality.

“Meremere power station built in the 50s, had originally people feeling very excited, and then it very quickly became outdated technology, often using poor-grade coal it wasn’t designed for and created a lot of smoke. People already had a sense that coal-fired power station had a big chimney and lots of smoke.

“There was that feeling for locals that a coal-fired power plant that couldn’t look and smell so great.”

The elephant in the room

That begs the question, if this is the year of climate tipping point and now-or-never action, is it all that sensible to keep a plant inimical to climate goals running?

The facility’s owner Genesis energy, a spin-off of the former Electricity Corporation of New Zealand, regularly features on the country's list of biggest emitters. Huntly is its final bastion of fossil fuels, belching out 970,000 tonnes of carbon dioxide in the year to July 2022, more than 1% of the national total. It is taking steps to alleviate its ongoing impact on the climate.

In February, a trial was run using Canadian produced wood pellets to fire the boilers and create steam. Successful, the trial was a “near perfect” swap from coal, says Westbury.

“It shows the way the world is going, and needs to go.”

Westbury says that sourcing the fuel was difficult.

“We had great difficulty in getting the trial fuel and that’s because everyone is trying to do the same thing.”

The day Stuff visited the plant was two days after stark warnings from the IPCC that the world must take immediate action to avoid planet-altering climate tipping points

When asked if that played into their thinking while working at the plant, Dodd said it was a matter of ensuring the market was given an option for a cleaner thermal power source going forward.

Fuelling that change would likely be biomass. According to Westbury, it affords the nearly same amount of energy for only 6% the emissions of coal.

“We’ve done our job in presenting an option. Saying ‘hey we still need electricity that you can store’. That biomass can follow on after the life of coal is a good solution. I guess it’s the government and the likes that need to step up.”

The public relations manager quickly added industry too had a part to play.

Throughout the plant you are reminded of the brutal realities of economics that shape this place. From the mothballed unit three, to turbines made by a company that has succumbed to globalisation and merger, to the fact that if the stacks atop Huntly are to stop spouting carbon, the market would have to play its part too.

“Renewables are cheaper, there won’t be any thermal plants built anytime soon,” Westbury says.

Huntly, then, really is the last of a kind.