Finding a better way – the circular economy

The biggest single industry in New Zealand for waste is building and construction.

So, with commercial construction at record levels, residential building consents peaking at 1970’s levels and massive housing shortages combined with anticipated additional demand from Kiwibuild – we must find a better way.

The solution is adopting circular economy thinking, not only easing the pressure on landfills but supporting New Zealand’s transition to a vibrant, low-emissions future.

Metal provides an established pathway through the circular economy.

This take, make, waste image of today’s linear economy from the Ellen MacArthur Foundation adequately depicts construction in our residential sector.

The Ministry for Environment (MfE) has estimated that over 3m tonnes of construction and demolition waste ends up in landfill each year[1].   BRANZ provides further insight, estimating that each new house generates over four tonnes of waste – comprising “timber (20%), plasterboard (13%), packaging (5%), metal (5%) and other (45%)”[2], and the bulk of this is new material.

A 2015 study by the Club of Rome suggests that the circular economy could bring 70 percent cut in carbon emissions by 2030[3].

What then is the circular economy? Basically, it is to ensure we can unmake, upcycle, reuse or recycle anything we make.

MfE is working with the Ellen MacArthur Foundation to transform New Zealand businesses and has a great introductory video here.

The Sustainable Business Network has been a leader in working with New Zealand businesses across the economy and has identified 6 key leverage points – Design, Demand, Infrastructure, Ownership, Emerging Technology and Legislation.

Why should Metals New Zealand be interested in the circular economy?

It all starts with design and if you haven’t read Cradle to Cradle by William McDonough (architect) and Michael Braungart (scientist, chemist, process engineer) then I suggest you should. They separate materials into two spheres – the biosphere and the technosphere and for the two spheres to be kept separate.

This MfE image helps reinforce the point:

Metals are the ultimate technical materials in a circular economy as the steel, stainless steel and aluminium are infinitely recyclable.

While we need to acknowledge the high energy, high emission process which create our metals, work is being done globally by large steel[4] and aluminium[5] processors to significantly reduce their carbon footprint. Locally New Zealand Steel has made significant progress in reducing energy use and 70% of its electricity is generated on site through co-generation processes[6].

Modern design and manufacturing processes enable optimal use of material, for example Steltech[7] delivers optimized beams and columns. Steel beams are frequently reused. Scrap metal is frequently upcycled by foundries into high value castings. Valuable scrap aluminium is recycled in New Zealand into high value aluminium windows – Omega windows have globally the lowest embodied carbon of any window manufacturer[8]

Little of our valuable metal ends up in landfill, (refer previously quoted BRANZ figures), because it is infinitely recyclable, it has significant commercial value and is traded as a global commodity.

In conclusion, the circular economy starts with good design and metals enable us to deliver on the circular economy.