U.S. organisations Eco Materials and Georgia Power have signed an agreement to remove 8 million tonnes of coal fly ash from a retired coal-fired power plant in Georgia, America.

The 15-year deal will see the repurposing of fly ash to produce low-carbon cement for infrastructure projects in Georgia and Florida.

Eco Materials have said that around 1.2 million tonnes of fly ash will be harvested annually, with 600,000 tonnes being saved from being sent to landfill.

The firm will construct a plant on-site top harvest the ash and is expected to finish with two years.

The project will be the second fly ash harvesting project, following a similar agreement Eco Material and Georgia Power announced in 2022 for fly ash harvesting at Plant Bowen in Bartow County, Georgia, where construction of a plant is underway, and harvesting is expected to begin by 2024.

“Most fly ash ends up in large infrastructure projects, including roads, bridges and dams, where specifications call for the durability performance benefits that fly ash use imparts,” says Eco Material CEO Grant Quasha.

He says more concrete producers would use the material, including in non-spec projects, if it were available.

The fine residue resulting from combustion of pulverized coal, fly ash is well known as a supplementary cementitious material (SCM) and has been in practice for decades, Quasha says. The American Coal Ash Association has reported a year-over-year increase from 11.1 million tons of ash to 11.9 million tonnes from 2020-2021, and that its use “improves concrete durability and significantly reduces greenhouse gas emissions associated with concrete production.”

By reducing need to manufacture cement, the process reduced about 12 million tonnes of greenhouse gas emissions in 2021, the organization says, with nearly 4.5 million tonnes of previously disposed ash being recycled for concrete products, cement kiln raw feed and more, an increase of 12% over the year prior.

In common practice, Eco Material suggests fly ash material will replace 20-25% of carbon-intensive Portland cement in concrete mixes, saying that cement and the concrete industry account for about 8% of global carbon emissions now.