My second article on embodied carbon has just been published in Canadian Architect magazine!
In this article, I discuss key factors that impact the embodied carbon of key construction materials such as concrete, steel, aluminum, wood, and insulation.
I also describe “blind spots within the blind spot” of embodied carbon, such as MEP systems, refrigerants, interiors, forestry, retrofits, and floor area per occupant.
In case you missed it, here is the first article I published last year, titled “Embodied Carbon - The Blind Spot of the Building Industry”.
I think one thing to keep in mind is that EAF steel is not primary steel production, but rather recycled steel, so depending on demand blast furnace steel is hard to get away from. Of course hydrogen reduced steel is around the corner which will significantly reduce the impact of steel production and may lead to net 0 emission steel (not sure about the mining impacts, etc.). I particularly like that you’ve tied the emissions intensity back to the electricity grid, for most materials this will dominate… except for concrete.
Flyash SCM is a bug bear of mine, because it is producing a revenue stream for coal power plants, and the attribution of emissions is hidden by the assumption that this revenue is <1%, as coal power becomes less competitve with renewables the attribution will need to change, and even with very little attribution the emission intensity of flyash swamps OPC. In my opinion the very difficult emissions from cement may need to be dealt with by circular economy design.
Finally - I couldn’t agree more with this statement
A bigger lever is choosing to retrofit existing buildings, where the structure and envelope are repurposed, taking advantage of the carbon already expended.
Thanks you for highlighting the importance of EC so well, Anthony.
I notice you mentioned need for efficient space planning, referring to current 34m2 per person UK and 68m2area pp in US. Cohen (2020) mentions ‘sufficient’ size per person of between 14-20m2 pp.
Am also passionate about a related ‘blind spot’ in cutting carbon i.e. growth in floor area. https://emeraldopenresearch.com/articles/2-2 (please see previous discussion thread on CLF).
It is critically important that we in the Global North (including US, Australia, UK etc dramatically reduce our consumption and seriously question the need for new buildings, especially commercial, when the South needs more infrastructure and facilities to overcome poverty. Do we really need so many new New York cities in the developed world?! We should consider other options, as Bringing EC Upfront (WGBC 2019) highlighted in ‘carbon reduction potential’ diagram on p.20, such as not building at all (100% reduction in EC) and meeting services via digital means, working from home etc, or building less and adapting existing stock. Responses to COVID-19 has shown that we CAN meet many needs while building less.
For global equity, we need to work within carbon allocations per person. In this regard, EU countries are devising carbon budgets for various types of buildings, related to overall country allocations.
We are researching this topic in Australia too, very interested to keep in contact.
Best regards
David Ness (Adjunct Professor)
david.ness@unisa.edu.au
Yes Will, making use of existing saves on carbon associated with new builds. This should also result in substantial cost savings when carbon price is introduced, as surely it must be.
I read that Lendlease estimated that a price of between AUD$50-100 per tonne of carbon would have resulted in EC liability of between AUD$15.30 - 30.6 million for its new International Towers project at Barangaroo Sydney.
Hi David, it’s a real shame that the carbon tax in Australia got pilloried, thanks in no small part to misinformation from the Minerals Council, New Corpse and the LNP. Here in Canada the tax is due to rise from $40 to $50 per tCO2e, but has been delayed due to the pandemic (not sure why though). One issue that I haven’t explored is how imports are accounted for, and the veracity of carbon accounting. It would be interesting to look into the effects that the tax has had on on producers and importers here, if anybody has a link or a paper!
Of course, for most materials, the emissions are dictated by the electricity source, and it’s great to see that solar is now the cheapest energy source worldwide, including against existing thermal coal plants. So I believe the shift to renewables will only accelerate, and EVs will overtake ICEs - the efficiency improvements of electrification are hugely beneficial, you can read more on this at Rewiring America, but the same should apply worldwide.
Going beyond the carbon issue we are still consuming far too many resources to be anywhere close to sustainable. With 100% electrification carbon sequestering materials may make new builds more viable, provided that they don’t degrade the environment too much. I’m keen to explore agricultural waste products as building materials, I think Ortech in Bendigo VIC has a great product, but if they’re powered from Loy Yang then the emissions are huge!
Thanks, that’s a good point. I should have included that point in the steel section, similar to how I discussed the limited supply of recycled aluminum to meet global demand.