A new house has been built in the Bahamas with an alternative concrete that squeezes CO2 out of the air. This housing is designed to combat climate change, and there are plans to build 999 similar homes.
This achievement was accomplished by former NBA legend and actor Rick Fox, who is now the CEO and co-founder of sustainable building materials startup, Partanna. The first house of this startup was opened today. If they succeed in the Bahamas, the goal is to make their alternative concrete a mainstream construction material that will reduce pollution from construction.
“I gave up my Hollywood career to work on climate [solutions],” says Fox. “I had to go into an industry that was new to me and meet people who looked at me as someone who deals with concrete.”
Concrete has proven to be a major source of greenhouse gas emissions, which are causing more intense storms, wildfires and other climate change-related disasters. The culprit is actually cement, a key ingredient in concrete that alone is responsible for more than 8 percent of global carbon emissions.
“My entry into the world of concrete was dictated by the simple need and necessity of innovation in my own country,” says Fox. In 2019, the Bahamas was devastated by Hurricane Dorian, which destroyed 75 percent of the homes on the worst-hit island of Abaco and displaced thousands of people. Fox was in Los Angeles at the time. “The closest I could do was to go on CNN and shout from the rooftops that we need to do something better,” he says.
Soon after, he met California architect Sam Marshall, whose home was damaged in the Great Woolsey Fire of 2018, one of the most destructive fires in the state’s history. Marshall has already “hit ten,” according to Fox. Together with materials scientists, they developed a method of making concrete without using carbon dioxide cement. Together they founded Partanna.
The couple is pretty tight-lipped about the process, but the main ingredients are spray from desalination plants and a byproduct of steelmaking called slag. By eliminating cement as an ingredient, Partanna can avoid the carbon dioxide emissions associated with it. Making cement requires heating to high temperatures in a kiln and causes a chemical reaction that releases additional CO2 from the limestone.
Partanna claims their blend can be made at ambient
x temperatures, so they do not need to spend a lot of energy. They also say the components bind CO2 from the air and trap it in the material. In the house, the material continues to expel CO2. Even if the structure is destroyed, the material retains CO2 and can be used as a reserve to produce more alternative concrete.
Thus, the startup can call its material and the newly constructed house “carbon negative”. The 1,250-square-foot house had to capture as much CO2 as 5,200 mature trees exhale annually.
Of course, accounting for carbon using trees is difficult. An investigation by The Guardian earlier this year found that 90 percent of rainforest carbon credits certified by one of the world’s most prominent carbon credit certifiers, Verra, were “worthless” because they likely did not actually reduce pollution. Verra also certifies carbon credits for Partanna. Fox says that the carbon dioxide Partanna exhales is easier to quantify than the carbon offsets of forests, and is not as vulnerable as forests that need to be protected from logging to store carbon.
It is also important to note that Partanna’s key ingredients, slag and slag, come from energy-intensive steel and desalination plants, which can expel large amounts of CO2 emissions on their own. Partanna does not count these emissions in its carbon footprint. “It’s not on us… It’s waste that we’re using for good,” says Fox.
“It’s good that they’re using waste,” says Dwarak Ravikumar, an associate professor in the School of Sustainable Engineering and Construction at Arizona State University. However, Ravikumar says, “we need to do a thorough analysis from a systems perspective to understand the overall impact on climate.” It’s important for the company to share its information so researchers can assess Partanna’s overall environmental impact and the scalability of its strategy, he says.