Chief Executive's Upfront
Innovative Cements to Reduce Emissions

The New Zealand concrete industry has highlighted its recent success in reducing emissions along with its vision to progress decarbonisation further in responding to the Climate Change Commission’s 2021 Draft Advice for Consultation.

Rob Gaimster, Chief Executive

The Commission’s advice offers guidance to the Government on how to implement an emissions reduction plan, and will be key in helping New Zealand play its part in reducing emissions under the Paris Agreement.

While the Commission should be applauded for its efforts in drafting such a comprehensive document, it is in parts overly prescriptive in its guidance on lower-emissions pathways.

Concrete NZ considers the market is best placed to determine the most efficient approaches for emissions reductions, and recommended that government facilitates meaningful engagement with industry to understand regulatory and resource needs to achieve emissions targets.

Government support will also be required to modify building and infrastructure design tools to incorporate the carbon cost, and in turn, optimise design for carbon footprint.

Concrete NZ also urged that the design life for buildings be extended from 50 to 100 years, and that only cradle-to-grave-to-cradle Life Cycle Assessments are used when selecting building materials for low-emissions construction.

EMISSIONS REDUCTION SUCCESS
Demonstrating to the Commission that the New Zealand concrete industry walks-the-walk is the fact that independent consultants thinkstep have confirmed a reduction in emissions from cement of 15 percent between 2005 and 2018.

The 15 percent reduction in emissions was achieved through the use of alternative kiln fuels in cement manufacture and a general shift to more efficient manufacturing processes.

CONCRETE INDUSTRY VISION
The Commission was also made aware that the concrete industry, under the Concrete NZ banner, has developed a vision which states that by 2030 it will have reduced its emissions by another 15 percent to achieve a 30 percent drop from 2005 levels.

This vision will be enabled through:

• using efficient energy sources for manufacturing and delivery processes,
• driving waste minimisation in manufacturing, delivery and construction,
• developing recycling processes to minimise the use of virgin materials,
• adopting new technologies where appropriate,
• being engaged with our local communities; and
• facilitating the increased uptake of low carbon supplementary cementitious materials (SCMs).

LOW CARBON CEMENTS
The increasing global use of SCMs to replace cement and therefore directly reduce embodied carbon dioxide makes sound ecological sense.

SCMs are derived from lower embodied energy materials, and can result in environmental benefits, improved concrete performance, and long-term cost advantages.

Typically, they are ground granulated blast furnace slag (waste from steel manufacture), fly ash (waste from coal combustion) or silica fume.

Industry is also working to enable the increased adoption of another type of SCM - natural pozzolans - or rather volcanic ash from New Zealand’s North Island Volcanic Plateau.

To help enable a better understanding and greater uptake of both industrial and natural SCMs, Concrete NZ is undertaking research, supported by the Building Research Levy, to assess classification techniques along with the fresh and hardened performance of SCM concrete – see pages 16-18.

Concrete NZ’s work in this area is important as the increased use of SCMs as a replacement for cement clinker will be important to the concrete industry reaching its emissions reduction target of 30 percent by 2030.