Pioneering sustainability in urban infrastructure

Carolyn Cox, sustainability manager and kaiwhakahaere rauora for City Rail Link gave insights into the journey Auckland’s largest transport project has gone on since 2016. 

Auckland’s City Rail Link (CRL) is one of New Zealand’s largest and most ambitious infrastructure projects aimed at significantly enhancing the city's public transport network. 

The CRL project, an underground railway project in central Auckland, aims to break through the dead end at Britomart Station and connect back into Maungawhau Mount Eden with two new stations in between. This line will double the capacity of the city’s metropolitan railway. At peak travel times up to 24,000 people will come and go from the new CRL stations per hour, with this number increasing to 54,000 over time - a significant step forward for Auckland’s future. 

However, an underground railway has a substantial footprint and involves the extensive use of steel, concrete, and workforce.  

The project’s sustainability journey began back in 2016, driven by a clear vision and commitment from CRL Ltd.’s leadership. Targets were set to reduce resource consumption and carbon emissions, aiming for zero waste to landfill and better social outcomes for Māori, Pasifika, and youth. 

One of the key achievements has been replacing cement with a less carbon intensive material, such as fly ash - a by-product of coal combustion. The project has reached a 12.5% replacement in shotcrete and 30% in most other concrete. This has helped shift the needle on acceptance of such replacements in New Zealand, although we still have room to improve compared to our Australian counterparts. 

Ambitious zero waste goals set by leadership are being met. Largely due to the strong culture of sustainability on site and in the boardroom, supported by over 12,000 people who have worked on the project. 

Procurement processes have been integral to the sustainability efforts, with bidders required to meet carbon and waste targets and demonstrate their track record and ambition around innovation. This has ensured that sustainability is embedded in every aspect of the project. 

The CRL project exemplifies how pioneering sustainability in urban infrastructure requires a clear vision, ambitious targets, and a collective effort from all stakeholders. By setting high standards and pushing the boundaries of innovation, we can create a more sustainable future for our cities and communities.