Pros / cons to CCS as the solution

Is it better to focus on not emitting in the first place?

Can CCS be used as a transitionary phase?

Types of Carbon Removal in Concrete:

• Mineralisation: Introducing captured carbon dioxide as carbonates that can be integrated into concrete, often improving its strength or reducing the need for cement
• Waste utilisation: Using waste concrete as a source of alkalinity for enhanced rock weathering in agriculture, as well as material reincorporated into concrete as aggregate or cement substitute.
• Cement displacement: Utilising materials such as biochar and calcium carbonate, made from captured carbon dioxide, to partially replace cement, which accounts for the majority of concrete emissions. Biochar and concrete go together well as both can be produced locally.

Challenges with CCS:

• The stream of CO2 needs to be more than 99.9% pure to reduce costs for compressing and storing the gas, whereas typical steel and cement plant flues consist of only 30% CO2.
• One way to isolate CO2 from the calcination process is to heat the limestone through a wall so that emissions from heating are separated from those from the limestone. The emissions from limestone are nearly pure and don’t require much further processing, reducing the cost. Such projects are ongoing.
• An additional option is building heavy industries in clusters to allow heat, materials and infrastructure for making and storing hydrogen, as well as collecting and disposing of waste CO2, to be shared. Such clusters are already being developed.