Microsoft has made an offtake agreement with Neustark for 27,600 tons of carbon removal over the next six years, using a process of storing carbon within recycled demolition concrete.
Neustark’s process includes capturing carbon from biogas plants then liquifying it for transport to construction waste recycling sites. The company then uses mineralization to bind carbon to concrete granules from demolished buildings, which acts as permanent storage for carbon removed from the atmosphere. These granules are then processed by recyclers to be used for roads and other concrete-based construction purposes.
Neustark said its carbon removal and storage technology is verified by the Gold Standard as measurable and permanent, with little-to-no risk for reversal.
“We turn the world’s largest waste stream -- demolition concrete -- and other mineral waste material into a carbon sink,” said Lisa Braune, head of carbon dioxide removal at Neustark. “Our solution makes an impact now: we have removed more than 1,000 tons of CO2 to date, and we are expanding our footprint quickly. Working with such carbon removal pioneers such as Microsoft significantly helps to scale our impact and the (carbon dioxide removal) industry as a whole.”
Microsoft, which has been active in obtaining carbon credits including in areas such as grasslands and forests, first began working with Neustark in 2022 to support its first successful carbon storage attempts, and the company has since scaled operations. Neustark currently operates 14 carbon capture and storage sites and aims to achieve 1 million tons of removed carbon by 2030. The new purchase also contributes to Microsoft’s goal of being carbon-negative by 2030.
Concrete and the built environment are known as major global emissions contributors, and demolition concrete also causes more than 1 billion tons of waste each year.
Creating new concrete requires typically high-emissions processes as well, so Neustark’s solution makes the use of recycled concrete even more environmentally beneficial. The company said it can store about 22 pounds of carbon per ton of demolition concrete. Its largest plants may store more than 2,200 pounds of carbon each hour in concrete granules -- the equivalent to the amount of carbon 50 trees may store in a year.
Additional companies are currently exploring the ability to store carbon in concrete, along with other solutions for reducing its emissions impact.
CarbonCure Technologies, for example, is able to produce low-carbon concrete mixes from captured carbon dioxide. Concrete recycling efforts and processes that involve low levels of embodied carbon are also being implemented to further decarbonize the industry.
