Du béton alternatif qui aspire le CO2 : Partanna et la révolution écologique dans la construction

Alternative concrete that sucks up CO2: Partanna and the ecological revolution in construction

The concept of alternative concrete capable of absorbing CO2 may seem like a far-fetched idea straight out of an environmental activist party, but the technology does exist. And it owes its existence to a former Lakers basketball player, who also got his start as an actor, although detractors of this franchise with 17 NBA championships may smile.

Former Lakers star Rick Fox has found a new playground, but this time, instead of donning shorts and dribbling on the hardwood, he's running his startup, Partanna, in home construction in the Bahamas. What sets these homes apart, the first of which was built in October 2023, is that they are built entirely from this durable concrete. The goal is to build 999 more homes with these sustainable materials. If the test is conclusive, or should we say if the "shoot" is validated, Partanna will be able to offer its materials throughout the world. Its goal ? Not only reduce pollution on construction sites, but above all contribute to the fight against air pollution thanks to its concrete technology.

Concrete is actually a major source of greenhouse gas emissions that cause more severe weather events, such as devastating storms and wildfires. The real culprit is none other than cement, an essential ingredient in concrete, which alone is responsible for more than 8% of global carbon dioxide emissions.

Rick Fox's desire to innovate in his home country led him to meet architect Sam Marshall, who, at the time they met, was rebuilding his house destroyed by fire. Marshall was working with a team of materials scientists and had developed a way to produce concrete without using carbon-intensive cement. Together they co-founded Partanna.

The duo keeps the manufacturing process relatively secret, but the main ingredients include brine from desalination plants and a byproduct of steel production called slag. By removing cement from the formula, Partanna manages to avoid the carbon dioxide emissions associated with it. Indeed, cement production generates significant climate pollution because it requires cooking at high temperatures in a kiln, triggering a chemical reaction that releases more CO2 from the limestone.

Partanna claims its mixture can cure at ambient temperatures, reducing energy consumption. Additionally, the binder ingredients in the mixture absorb CO2 from the air and retain it in the material. In a house or building, the material continues to absorb CO2. Even if this structure is demolished, the material retains CO2 and can be reused as aggregate to make more alternative concrete.

This is how the start-up can claim that its material and the recently built house are “carbon negative”. This 1,250 square foot structure is estimated to have captured as much CO2 as 5,200 mature trees in a year.

However, it is important to note that calculating carbon emissions from trees is complex. A Guardian investigation earlier this year found that 90% of carbon offsets for rainforests certified by one of the world's leading carbon credit certification bodies, Verra, were "useless" because they were unlikely to leads to real reductions in pollution. Partanna has also obtained certification from Verra for its carbon credits. Rick Fox argues that CO2 captured by Partanna is easier to quantify than forest offsets and is less vulnerable than forests, which must be protected from deforestation to store carbon.

It's also worth noting that Partanna's key ingredients, slag and brine, come from energy-intensive steelmaking and desalination facilities, which can produce a lot of CO2 emissions themselves. Partanna does not take these emissions into account in its carbon footprint, arguing that it is waste that they use for a good cause.

Dwarak Ravikumar, assistant professor in the School of Sustainable Engineering and the Built Environment at Arizona State University, believes that using this waste is a good thing. However, it highlights the need to carry out an in-depth analysis of this innovation from a system perspective in order to understand the overall climate impact. It is essential that the company shares its data to allow researchers to assess Partanna's overall environmental footprint and the large-scale viability of its strategy.

Partanna is not the only company in this market, several start-ups have embarked on this path. Even the giant Microsoft is working on a similar solution for its data centers. We are thus entering a new era which could well shake up the habits of real estate developers and large-scale construction sites around the world. A major shift towards more environmentally friendly construction appears to be underway.

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