After 33 years generating energy the Meremere power station was mothballed and has recently been dismantled. The sheer amount of asbestos in the boiler house made demolition of the building a complex project. BY PAUL HALTON
The Meremere power station is an instantly recognisable Waikato landmark. The plant sits beside State Highway One, midway between Auckland and Hamilton. For years the coal fired plant produced base load electricity, but now it’s undergoing a transformation.
Meremere was New Zealand’s first thermal power station and dates back to the 1950s. At the time, many different options were considered for the power station, but in the end a coal-fired power station with six boilers and an output of 210MW was decided upon.
The technology for the plant dated back to the 1930s but had a proven track record overseas. The plant boasted one innovation; the use of the Waikato River for cooling did away with the need for cooling towers.
Construction began in 1956 and was completed in 1958. Although, instead of making the most of its vantage point overlooking the Waikato River, the plant faced south into the hillside.
Coal from the Maramarua field supplied the plant via a six-mile long aerial ropeway. The plant used 800,000 tonnes of coal per year.
However, the plant ran into problems with Waikato coal. Tests on the power plant had used British coal – the softer Waikato coal produced much more fly ash and no easy remedy could be found.
The problem was eventually solved in 1982, when the plant underwent a $20 million refurbishment, which removed nearly all the fly ash. This kept the plant in operation until 1991, when it was finally decommissioned.
After 33 years of work, the plant had come to the end of its working life and become uneconomic to run. It was then mothballed until Genesis Energy, which had inherited the plant when the Electricity Corporation of New Zealand was split into three, began work to dismantle the plant and find a new use for the remaining buildings.
This has been a gradual process. The latest work, undertaken by Nikau Contractors, is stage four of the renovation and almost completes the makeover.
“It’s the end of Meremere as a power station, but the remaining turbine hall might still have a use for someone who needs a large building of aircraft-like proportions,” says Richard Gordon, public affairs manager for Genesis Energy.
Nikau Contractors carried out the demolition of the power station’s six boilers and the boiler house. It was an exceptional job says director John Stil.
“It wasn’t all beer and skittles. This was one of the biggest demolition jobs in the country, and it took more than two years to complete,” he says. “One of the things that made it such a big job was the amount of asbestos contained in the building.”
Asbestos was once a common building material used for its insulating properties. It’s a mineral fibre and if disturbed, the fibres can become airborne and pose a serious health risk if inhaled.
Removing asbestos requires careful handling. The first step was to completely seal the building, to ensure the hazard was contained. Samples of the asbestos were then sent to the laboratory for testing before a plan of action was decided.
As asbestos is such a hazardous material, workers have to be specifically trained in its safe removal. Here, Nikau Contractors has a particular advantage, says Stil.
“Luckily we’ve got seven guys on staff qualified to do this work. The guys had to wear fully protective clothing including facemasks and power packs,” he says. “The site was sealed and if you were coming out of the building there was a decontamination area you had to pass through.”
Once the asbestos had been cleared, the site was opened up to complete the rest of the work. Dismantling the boilers was a tough job, as each of the six boilers weighed around 1000 tonnes.
“Usually you would start at the top of the boiler and work down, but we couldn’t do that. Instead we had to start at the bottom and work up.”
Once removed from its location, each boiler was lowered to the ground and then dismantled using a gas cutting plant.
The size of the Meremere boiler room meant a lot of scaffolding was required and workers had to be trained in working at heights. It’s no surprise that health and safety considerations were paramount to the project.
It was Nikau Contractors experience in demolition and asbestos work, combined with its skilled workforce, which ensured the project was completed successfully. The project also involved close monitoring from the Department of Labour, which conducted regular site audits. Genesis Energy also appointed Tonkin and Taylor to act as consultants.
“The way all parties worked together to bring the project to a successful conclusion can only be commended,” says Stil.
Nikau Contractors has won numerous awards for its health and safety work and has tertiary level accreditation for ACC health and safety management practices.
“We take health and safety, and environmental considerations extremely seriously. We are always trying to ensure we are at the forefront of the industry,” says Stil.