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Artist’s impression of the completed Britomart Station once the CRL tunnels are built – note the train emerging from under the existing CPO building from the CRL tunnel

CRL wins New Zealand’s highest sustainability accolade

Auckland’s City Rail Link (CRL), presently under construction in downtown Auckland, is setting the benchmark for delivering sustainable infrastructure in New Zealand – an aim that’s been recognised with the Supreme Award at this year’s NZI Sustainable Business Network Awards.

CRL chief executive Dr Sean Sweeney says that sustainability is a cornerstone of thinking in the CRL team. “We aim to build New Zealand’s largest transport infrastructure project without using unnecessary resources or creating unnecessary waste. Once built, the CRL will give people more sustainable transport choices, and we want to make sure we are sustainable in the process of delivering it. We aim to save over 4000 tCO2e (tonnes of carbon dioxide equivalent) of greenhouse gas (GHG) emissions during construction – that’s equivalent to around 4500 Auckland to London flights.”

Electrically-driven bentonite plant outside Britomart Station is used to install the diaphragm walls

Dr Sweeney says the CRL, opening in 2024, is the key that will unlock Auckland’s public transport network. It will transform the iconic downtown Britomart Transport Centre from a dead-end one-way station into a two-way through station, so more trains can get in and out of the city. It includes 3.45 km of new dedicated underground railway that will connect with other rail lines to benefit Auckland’s entire rail network.

A standard for infrastructure

The project adopted the ISCA (Infrastructure Sustainability Council of Australia) rating tool. To date it’s the only New Zealand project to be awarded two leading ratings: one each for Contract 1 (the Chief Post Office and Lower Queen Street construction) and Contract 2 (Albert Street) works.

“There is no New Zealand sustainability standard for infrastructure, so we have embraced and enhanced the ISCA framework, working with mana whenua to make it more appropriate for the New Zealand context,” says Dr Sweeney.

Sustainability includes both social and environmental elements. CRL is also seeking to create opportunities to contribute to society through the delivery phase by maximising training and employment opportunities, building capacity, and upskilling the workforce.

“With an estimated 1600 jobs on offer in the project at peak construction, we’re targeting employment for Maori, Pasifika and youth, along with others marginalised in the workforce. To be successful, companies wanting to win contracts for construction will need to demonstrate how they are going to help us achieve this social outcome,” Dr Sweeney adds.

Artist’s impression of Lower Queen Street after construction is completed

Efficient design and construction

A key objective of the project is to optimise resource use over the lifetime of the CRL through efficient design and construction.

To measure how successfully CRL has been in meeting this objective, the energy, materials and water footprints were calculated for the early design, and the detailed design was then compared against these footprints to quantify improvements.

The target for construction is to at least stay within the projected detailed design footprints – and ideally improve on them. Resource use is being tracked against these footprints. During detailed design, the team was able to 
reduce the projected construction and operational energy-use footprints for Contracts 1 and 2 by 29% and 25% respectively.

This is a projected saving of nearly 
2500 tCO2e of GHGs during construction and nearly 15,000 tCO2e over the 100-year operational design life.

Initiatives for resource reduction were identified through exploring alternative construction methodologies and running resource-reduction workshops, at which contractors were active participants.

Initiatives so far have included:

  • • 
Replacing diesel generators with grid-connected transformers – this has saved 200,000 litres of diesel to date
  • • 
Training haulage drivers in fuel-efficient techniques – this is being implemented not just on the CRL, but across the subcontractor’s 100-plus fleet
  • • 
Commissioning from a New Zealand manufacturer 50 mm reinforcing bar for underpinning the 19,000 tonne Central Post Office (CPO) building
  • • 
Using waste power-station fly-ash as a partial cement replacement in some concrete
  • 
• Changing the piling methodology for the underpinning of the CPO building to diaphragm walls rather than secant piles, reducing the amount of materials needed.
  • Example of greenhouse gas tracking against projections – this is Contract 2’s construction energy emissions

Zero waste to landfill

“We’ve also set an aspirational target of zero waste to landfill,” says Dr Sweeney. Construction waste makes up around 48% of all waste sent to landfill, and represents wasted materials, so CRL is reducing waste by reusing materials on and off-site, sending resellable items to community recycling centres, sending used materials to Green Gorilla for sorting and recycling, sending excavated spoil to the Three Kings Quarry as part of the quarry’s rehabilitation for housing, and using recycled crushed concrete for backfill.

Downer NZ and Soletanche Bachy JV was awarded Contract 1 and Connectus (McConnell Dowell and Downer JV) Contract 2. Dr Sweeney says the attitude and commitment of the project team and contractors to making sustainability an integral part of building the CRL is already making a real difference. “It’s saving money and resources and we are holding ourselves up as an exemplar for the industry.”

Supreme winner

This commitment was recognised at a black-tie awards ceremony on 22 November when CRL was awarded the Supreme Award at the NZI Sustainable Business Network Awards, New Zealand’s pre-eminent and longest-standing sustainability awards. It also received the Efficiency Champion award.

Rachel Brown, CEO of the Sustainable Business Network, says CRL has busted through construction and infrastructure industry norms, and proven the infrastructure industry can reduce GHG emissions and its environmental impact while developing Auckland’s much-needed public transport infrastructure.

“By taking a long-term view and calculating a whole-of-life footprint of 100 years for the project, CRL has put sustainability at the core of every decision from the outset,” she says.

“As New Zealand’s largest civil infrastructure project, it is leading the change in the way infrastructure projects are designed and delivered. A success factor behind being able to achieve CRL’s goal of zero waste to landfill has been supporting and educating the contractor companies and their employees to avoid, reduce, reuse, recycle and recover as much waste as practicable,” she adds.

“New Zealand’s construction industry contributes 40% of the total waste going to landfill in Auckland, and CRL has proven this doesn’t have to be the case. To have the largest civil infrastructure project ever built in New Zealand start with a goal of zero waste means CRL has the potential to show the wider sector the real value of integrating best practice throughout design and construction. It’s a great showcase for what can be delivered.

“The CRL will be a tremendous part of Auckland’s public transport infrastructure. It will help demonstrate how New Zealand can move to a low-carbon, circular and more accessible city. CRL exhibits best practice that provides an excellent model for other businesses to follow.”


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