A look inside the Kara¯piro Power Station
Mercury’s Whakamaru and Aratiatia modernisation projects will be completed by the time it comes to upgrade Kara¯ piro.
Mercury hopes that will mean limited impact to the overall output from its Waikato hydro scheme.
Smart technology has been added to monitor the performance of the plant, before and after the refit.
‘‘We want to get a baseline of what the turbines are delivering now and what the new ones deliver,’’ Adlam said.
‘‘That way we can go to our suppliers with data and tests to show whether or not they delivered what we asked for.’’
Earlier, Kedian and Adlam showed the major rehabilitation work on the spillway, which is an overflow channel the power station can use to release extra water.
From the outside it looks like a giant concrete slide from the top of the dam to the bottom of the power station, emptying into the Waikato River.
Every section of the concrete structure is being meticulously inspected and tested to identify degradation.
Where there are problems, a square section is removed and the area is strengthened.
Part of the slipway is submerged at the bottom of the power station and divers are underwater, testing the strength of the concrete there too.
Adlam also shows the three transformer units sitting outside the main building.
‘‘Your phone has a charger that plugs into the wall, that is a transformer, it is taking 230 volts down to 5 volts for your phone.
‘‘These transformers are doing something similar, to move electricity from the power station to the network.’’
Kara¯ piro Power Station supplies energy to the national grid via transmission circuits to Hamilton, Hinuera and Te Awamutu.
Adlam lives in nearby Maungatautari and before that in Cambridge, close to the Kara¯ piro plant.
He knows the power station better than most. His career working in various roles in hydroelectricity now spans
37 years.
For the past four months, he has been working as Mercury’s liaison with the project group upgrading the Kara¯ piro station.
Back in the control room, Adlam said he was excited about the changes ahead for the Kara¯ piro plant and the others on the network. ‘‘I think from the outside you won’t see much change but what we are doing is changing the technology inside each of the plants.
‘‘A lot of the systems we have here are mechanical and have been running for 70 years.
‘‘They will be replaced by computer systems that will have a much smaller footprint, so there will be huge gains.’’
Many of the dials on the wall of the operations room are the same ones the Queen looked over during her visit and still help run the power plant.
Adlam said that at one stage the plant would have been staffed 24/7, one person on the floor and one to start the machinery and to carry out routine checks.
Earlier in the plant’s life there would have been many more staff, like a manager, station manager, clerk and an outside gang.
‘‘Now, with automation, one person controls the whole river, nine power stations from Taupo¯ to Hamilton, with the press of a button.’’
The hydro power station had endured its share of droughts and floods, said Adlam.
Water levels were lower than normal during the 2019-20 drought and that required close monitoring of Lake Taupo¯ , the Waikato River’s origin source from which all of the power stations ultimately draw their water.
Adlam recalled the late 1990s as another period when water levels dropped substantially because of a severe dry spell.
There was also a record of a major flood in the early 1960s, which took out the access bridge to the main plant. A photo of the flood hangs on the wall in the control room.
Adlam said that earlier in his career, automation and computers frightened him.
‘‘I was based at Arapuni when automation came in and I was a non-believer in the changes they were trying to make.
‘‘I looked at it and thought, nah, it is not going to work but I did not have the whole picture.’’
Adlam said major automation systems were introduced in the early 1990s and he had tried to take a severance package on offer to exit the industry.
‘‘But my manager saved me from myself and said: that is not an option for you.
‘‘I was scared of computers but my manager said we will teach you, and I went to join the team in Hamilton to learn.’’
In 1992, the Kara¯ piro power station was automated and in 1994 was remotely controlled by the Northern Generation Control Centre.
Adlam worked at the control centre for 13 years, helping to run the power stations on the river.
Tired of the shift work, he then moved into the resource consents department and attended hearings, learning more about the permits, safety and management expectations of the industry.
‘‘Then an opportunity came to work as lead, covering all the river again.
‘‘But now I have had enough of the managerial thing and I have come back on the tools, kind of, with Mercury.’’
Adlam said he had packed a lot into his 37-year career, something he attributed it to his managers who gave him a chance to adjust and grow.
The Cambridge Museum has an extensive collection of newspaper articles and photos tracking the development of the Kara¯ piro Power Station since its inception in the 1940s.
In the future, the museum plans to develop a special collection.
The museum also hopes to work with Mercury Energy to find a place to exhibit the company’s interactive educational display of the Kara¯ piro Power Station.