According to foreign media reports, the six-year competition to collect carbon dioxide emissions from operating power plants and convert them into useful products has ended with two winners, whose technology is expected to reduce the environmental footprint of concrete. The $20 million Carbon XPrize awarded cash prizes to two teams from North America who were able to demonstrate how their methods could eliminate meaningful CO2 and produce concrete with comparable or even better performance than conventional materials. The
Carbon XPrize began 2016 with nearly 50 teams from around the globe, reducing to 10 finalists in 2018. The teams were then asked to demonstrate their technology at a coal-fired power plant in Wyoming or a natural gas-fired power plant in Calgary, Canada, where they were tasked with demonstrating their approach in an industrial setting. The winner in both places is the one that converts the most CO2 into the product with the highest value and keeps its own CO2 footprint, land, water and energy use to a minimum.
Canadian startup Carbon Cure Technologies has won a $7.5 million prize in the Calgary competition. The team's approach involves injecting a highly specific amount of captured CO2 into the reclaimer system at the concrete plant, where it reacts with calcium ions in the cement to form a nano-sized mineral that can be incorporated into the concrete mix and increase its compressive strength by up to 10%.
The necessary hardware can be retrofitted into an existing concrete plant in a single visit, and a valve box feeds precise doses of carbon dioxide from a tank into the concrete as it is mixed. As a result of this adjustment to the formula, concrete can be produced with less fresh water, less solid waste disposal, and more importantly, less cement, which is a particularly energy-intensive material because of the extremely high temperatures involved.
Meanwhile, the $7.5 million winner in Wyoming is the CarbonBuilt team from UCLA, whose technology involves capturing carbon dioxide from the flue gas stream of a power plant or cement plant and injecting it directly into the concrete mix, where it is converted and permanently stored. This method reduces the carbon footprint of concrete by more than 50% and reduces the amount of ordinary Portland cement required by 60 to 90%, the UCLA
Carbon Built team said. At the same time, the concrete is as strong and durable as traditional concrete, and as part of the team's final demonstration last year, it was molded into concrete blocks that can store 340 grams of carbon dioxide each. This also proves that the technology can consume 135 kilograms of carbon dioxide in 24 hours. "Concrete is one of the world's most abundant materials and an important front in the fight against climate change," said Marcius Extavour, vice president of climate and energy
at XPRIZE. Portland cement is a key ingredient in binding concrete and giving it strength, and its production accounts for about 7% of global carbon dioxide emissions. Concrete is also a material that can readily use CO2 as an input, as the winning team has demonstrated very clearly. Now, deploying their technology to avoid and reduce emissions from heavy industry will become a game rule for global decarbonization in the fight against climate change.
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