Environment & Energy

Judi Lynn

(160,545 posts) Tue Oct 24, 2017, 06:21 PM Oct 2017

From seeds to skyscrapers, these wooden towers are eating CO2

Using wood to build our tower blocks could cut global emissions by 31 per cent
By ALEXANDRA SIMON-LEWIS
Sunday 22 October 2017

Timber towers are branching out around the world. Designed to trap thousands of tonnes of carbon within their walls, wooden skyscrapers are more than just architectural statements - they're monoliths of modern environmentalism.

"I can hold the number of tree seeds it took to build Murray Grove in my palm," says Andrew Waugh, of Waugh Thistleton Architects. His flagship timber build in Hackney, London, completed in 2008, is nine storeys high and constructed entirely from cross-laminated timber (CLT). This wood is a natural storage source for CO2 and was harvested from a sustainable forest. Once shaped into timber panels, it was assembled on site with cordless screwdrivers, with no need for hammers or toxic chemicals - slotting into place like a giant honeycomb.

The timber boom started from tiny seeds, but it's now starting to take root. A report by the Council on Tall Buildings and Urban Habitat found that 21 such structures with a height of more than 50 metres will be completed by 2019. "People want to be connected to nature, even when they're indoors," says Philip Vivian, director of design firm Bates Smart. "It's funny, because before we built using concrete and steel, we used wood." His project, the nine-storey 25 King building in Brisbane, Australia, is set for completion in 2018. "Research predicts that if we used mass timber in place of concrete and steel, we could cut global emissions by up to 31 per cent."

In Bergen, Norway, TREET ("tree" in Norwegian) was assembled in 2015, "almost like building with LEGO", says the company's chief project manager Ole Herbrand Kleppe. Its 62 apartments were designed as prefabricated modules.

More:
http://www.wired.co.uk/article/wooden-tower-blocks-carbon-environment

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From seeds to skyscrapers, these wooden towers are eating CO2 (Original Post) Judi Lynn Oct 2017 OP

Nevertheless, it is useful to have a sense of scale for this sort of thing. NNadir Oct 2017 #1

Don't light a match near one of these.... roomtomove Oct 2017 #2

NNadir

(33,525 posts)

1. Nevertheless, it is useful to have a sense of scale for this sort of thing.

Reply to Judi Lynn (Original post)

Thu Oct 26, 2017, 01:03 PM

Oct 2017

Currently, the world is dumping about 35 billion tons of the dangerous fossil fuel waste carbon dioxide per year.

This represents about 9.55 billion tons of carbon when corrected for the molecular weight of CO2 compared to carbon.

All of the straw left over from all the grain grown in China amounts to about 270 million tons, or about 3% of all the carbon dumped in the atmosphere in the form of CO2, and corresponding to about 670 million tons of straw, treated as pure carbohydrate.

These figures may be calculated in the paper found here: Controlling Air Pollution from Straw Burning in China Calls for Efficient Recycling (Bing Li†*, et al Environ. Sci. Technol., 2012, 46 (15), pp 7934–7936)

The link in the OP reports that a 22 story wooden building using this technology would sequester 3 million kilos of carbon, or roughly 3000 tons.

Thus in order to sequester the carbon dioxide released as dangerous fossil fuel waste, we would need to build 3.2 million 22 story buildings using this technology every year.

This calls into question what a "sustainable forest" is.

Three million kilos of carbon corresponds to 250 million moles of carbon

As the name "carbohydrate" implies - even if it is structurally nonsense - this requires 250 million moles of water incorporated into the wood, ignoring evaporation, transpiration, run-off etc.

This corresponds (again only water incorporated into the structure of the wood) to 4.5 million tons of water per building. To build 3.2 million buildings of this type would require about 14 trillion tons of water, never mind run off and evaporation, fresh water, never mind wood that is lost to disease, fires and heat waves.

I believe that future generations will need to remove carbon dioxide from the atmosphere because of our irresponsibility and airhead useless approaches to addressing climate change.

To the extent it is sequestered as wood, I'm for it, so long as the entire planet is not deforested Easter Island style.

But calculations of this type offer a caveat on how difficult this engineering problem is. There are no facile solutions; particularly when each person living shuffles on to generations not even born yet, the responsibility for addressing the crisis. We have no rational plan to stop using dangerous fossil fuels. None.

That's reality.

roomtomove

(217 posts)

2. Don't light a match near one of these....

Reply to Judi Lynn (Original post)

Thu Oct 26, 2017, 02:57 PM

Oct 2017

but hopefully they have an EFSR sprinkler system.....

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