Going green… building green


Several great leaps forward in the steel sector recently have signalled that zero carbon steel is within our grasp. The green future of steel might have struck many as laughable even a half-decade ago – but the advancements being made locally and globally are positioning steel to become a low-emissions leader. As COP26 has made clear, the global community is far off-track in limiting global temperature rise to 1.5°C.

Dr Troy Coyle brings more than 20 years’ experience in innovation management across a range of industries including materials science, medical radiation physics, biotechnology, sustainable building products, renewable energy and steel. She is a scientist with a PhD (University of NSW) with training in journalism and communications.

Steel and iron production is currently the single largest industrial source of CO2 emissions in New Zealand, representing 55% of industrial emissions and around 5% of total gross emissions. Carbon is primarily used in the steel-making process as a reductant, rather than an energy source. Aggressive curtailment of carbon emissions is needed, and the good news is that steel is significantly involved in Aotearoa’s circular economy in line with New Zealand’s international commitments.

Alternatives to coal

There is ground-breaking work being done in several countries to replace coal in the steel-making process. Sweden’s Volvo Construction Equipment is set to roll out concept vehicles and components made of ‘fossil-free’ steel supplied by steelmaker SSAB. The manufacturer says it aims to have this steel used across all its products, with rapid progress being made after the steel was unveiled in October last year. Volvo CE’s path to commercialisation of this product (versus steel made using coal) is timed for 2026.

Swedish-Finnish joint venture Hybrit is using hydrogen to replace coal and produce sponge iron which is refined into steel; Swedish venture H2 Green Steel is also using hydrogen technology, backed by vehicle manufacturers such as Mercedes-Benz and Scania. It intends to start production in 2024, and to produce five million tonnes of zero-emissions steel a year by 2030. Companies in Germany, Austria, and South Korea are exploring hydrogen-powered steelmaking. One of them, ArcelorMittal, is researching and developing the replacement of coal in a blast furnace with renewable sources of carbon such as biomass or waste plastic.

Meanwhile Boston Metal, an MIT start-up, produced its first batch of steel in 2018 by using electrolysis to separate iron from its ore, releasing no CO2. Carbon and other metals are added to this iron to produce different types of steel. Drawing on investments from Breakthrough Energy Ventures and BMW, the company aims to produce a commercial-scale demonstration plant by 2025.

Here at home, Victoria University of Wellington is researching novel ways to use hydrogen as the reductant in New Zealand’s unique iron sands-based steelmaking process. And there are many other areas in which our work and lateral thinking puts New Zealand alongside others at the forefront of the global industry in measuring, analysing, calculating, and offsetting the carbon effects of steel while we move towards a coal-free future.

HERA commissioned thinkstep-anz to estimate the sector specific recycling rate, and the consequent study estimated that 85% of steel scrap from building and construction waste is recycled.
Photo Credit: Phoenix Metalman Recycling

Aotearoa’s world-leading carbon offsetting program

Hōtaka Whakakore Puhanga Waro, the zero carbon steel program, marks a global first for the construction sector by offering a zero carbon option for most steel products used in New Zealand. The offsetting program includes a robust set of rules to determine the underlying requirements for calculating the emissions for offsetting; this ensures program integrity.

Emissions are offset via Ekos, a leader in carbon management and environmental financing, through the calculator; the offsets are sourced from native forest projects. These projects deliver multiple biological, ecological and social co-benefits beyond simply carbon sequestration.

This program can be expected to change the conversation around the carbon performance of steel, with the sector knowing that a reliable option for net zero carbon steel now exists. In general, the construction industry is having a lot of conversations around carbon in steel, with MBIE having developed two emissions mitigation frameworks under the Building for Climate Change.

Hōtaka Whakakore Puhanga Waro is a game-changer for steel, a known hard-to-abate product. The novelty of the program is that it covers a number of different steel products. It includes painted steel used in roofing and cladding, rebar used in concrete, light-gauge steel framing, heavy structural steel and stainless steel. We are not aware that a program of this type, at this level of detail, currently exists anywhere else in the world.

The main users of the program will be building product suppliers or fabricators, who may decide to bring it into their front end to offer zero-carbon options to their customers or end-users (building owners). Suppliers can use the program to bid for projects offering a zero-carbon option (with the anticipated offsets included in the quoted fee), leaving the end-user to pull an affordability lever or a carbon lever. For homeowners and renovators, the program can be a tool to prompt broader conversations around consumer decisions and find the right balance between ‘building beautiful’ versus ‘building sustainable’.

Steel recycling and the circular economy

Two recently published reports are changing the landscape of how steel is perceived and used in Aotearoa. Steel is a hero of the circular economy, with the Steel Recycling Report outlining the estimated steel recycling rate in New Zealand. HERA commissioned thinkstep-anz to estimate the sector specific recycling rate, and the consequent study estimated that 85% of steel scrap from building and construction waste is recycled. At 85% recovery, the savings in global warming potential per tonne of steel scrap generated in the sector is 1,249 kg CO2-equivalent. If 100% recovery could be achieved, there are potential savings of 1,473 kg CO2-equivalent.

Timber, on the other hand, is currently going mostly to landfill, where it will release carbon back into the atmosphere. This report demonstrates the significant role that steel plays in Aotearoa’s circular economy, supporting a whole industry in steel recycling and contributing significantly to global carbon emissions reduction.

The second report, HERA’s Position Report prepared for the Sustainable Steel Council, explained steel’s contribution to a circular economy. A well-structured circular economy is based on lifecycle analysis: reduce, reuse, reconfigure, recycle, and retrofit are all benefits of steel, as is resilience, with steel performing extremely well in New Zealand’s severe seismic conditions. This means that our steel-based buildings last longer and require less repair work, saving resources.

Materials passport program

Another element of the circular economy, materials passports have largely been developed in Europe. A material passport for structural steel will enable it to be taken from one building or application and moved to another at the end of life. It provides a record of what the material’s quality is, where it has been, and the stresses it may have been under.

One of the barriers to steel reuse is the desire to avoid risk or liability associated with how it has been used or exposed, such as in an earthquake. The passport allows for safe reuse, advancing circularity in the supply chain.

HERA is proposing to develop a passport for structural steel as the first materials passport in Aotearoa. This will create a template to streamline the process and pave the way for other materials to be similarly tracked and reused.

Certification and the Living Standards Framework

New Zealand’s sustainable steel certification programme is led by the Sustainable Steel Council (SSC) and measured against Treasury’s Living Standards Framework (natural capital). It has now been underway for around 18 months. The Framework has three levels and includes prompts for analysing wellbeing across the levels: these prompts are distribution, resilience, productivity, and sustainability. About 70% of structural steel products have achieved certification, and HERA is helping others through the certification process, which enables businesses, especially SMEs, to build their skills and capacity, be consistent with larger-sector businesses, and keep up with the expectations of government and the business community.

Guidance for calculating carbon footprint case study

HERA is always willing to be a guinea pig for any zero carbon advancements it is asking industry, partners, or consumers to consider, and the calculation of our operational carbon footprint was no exception. The process was not onerous or costly but is essential to progress towards carbon neutrality, and the rigorous and independent process we undertook to calculate HERA’s carbon footprint yielded a case study that is available on the Sustainable Steel Council’s site.

In that case study, we include a link to our inventory which itemises each activity or item considered in our calculation and can be used to assist your business in taking the first steps towards going zero carbon. The calculation helps you determine your offset requirements, identify the activities that are contributing most to your footprint (i.e. where your efforts are best focused), and gives you tools to track your performance and improvements.

In our own zero carbon journey, we have offset against our calculated emissions, obtaining certified Zero Carbon Business Operations via certified carbon credits with Ekos.

Aotearoa Transformation Agenda and Plan

We’re asking our industry to step up by signing and committing to the Aotearoa Steel Industry Transformation Agenda and Plan. We want this accord to inform strategic business plans, and our industry to holding itself accountable and measure performance against the Agenda.

Along with several other industry organisations HERA is a chartered member of the Aotearoa Steel Transformation Agenda, which is a blueprint to position the steel industry for a sustainable future. It is based on the Living Standards Framework and enables members to promote their contributions to the Framework, leverage it in tenders and PR, and identify industry priorities for Government support.

The Agenda sets out the goals for the industry’s sustainable future, and the plan enumerates the actions to be undertaken – in the immediate term (up to 12 months), medium and long terms.

From a materials perspective it covers carbon and stainless steel across all steel products and applications, including (but not limited to) steel roofing, light gauge framing, stainless steel manufacturing, and structural steel fabrication.

It is a voluntary process, and those who commit will buy into its value and our mission to be an industry which challenges our behaviours that inhibit transformation, so we can collectively prosper and positively influence the wellbeing of New Zealanders.

Our sustainability FAQs resource

To help engineers and specifiers understand what is at play in our industry and the sustainability credentials of steel – progress is rapid and it’s not always easy to keep up – HERA has compiled a to-the-point reference list of frequently asked questions. Our intention is that our core operators in the industry can apply these to their own work and use the information to spread the sustainability word widely. Check out the list to cover off your own questions about zero carbon steel, steel recycling, the circular economy, imported vs locally produced steel, structural steel reuse, Green Star credits, sustainability roadmaps, and much more. These FAQS are updated regularly.

Innovative Kiwi group chalks up big emissions win in construction design

New Zealand’s Donovan Group specialises in construction technology innovation. In a 2021 Building 4.0 CRC study at Monash University in Melbourne, the researchers found that a unique Donovan Group-designed structural system used in the construction of large-scale steel commercial and industrial buildings results in a reduction of carbon emissions of more than 40% compared with traditional steel construction methods.

The system is built by Donovan Group’s Coresteel Buildings, which is now using the system to drive change in the local construction market. The Group says the innovative patented tapered box beam design – known as DonoBeam – was co-designed with BlueScope Steel in 2015 and has been used in more than 200 buildings in New Zealand to date. It represents a major step towards the reducing greenhouse gas emissions created by the construction industry which, globally, accounts for up to 40% of all greenhouse gas emissions. DonoBeam uses fewer raw materials and is typically lighter, resulting in fewer transport emissions to building sites. Pre-fabrication of the structure also cuts construction time on-site.

The Monash study evaluated the potential environmental benefits of the DonoBeam structures compared to traditional systems. The results revealed savings of up to 47.5% in steel emissions, and up to 32% in transport emissions.

The company says alongside the significant cost-savings in steel, DonoBeam delivers larger spans and greater design flexibility. This results in more unobstructed space inside a building, with clear spans out to 75 metres or even larger when propped.

DonoBeam uses fewer raw materials and is typically lighter, resulting in fewer transport emissions to building sites. Pre-fabrication of the structure also cuts construction time on-site.