Program Details:

The C3 protocol for the offset purchase includes the following assumptions:

• On a national level, for each metric ton of Portland cement (ASTM C150) clinker produced, one metric ton of CO2 is produced.
  
• Offsets occur at the point of blending.
  
• Offsets are based on the Portland cement used by weight compared to a baseline mix.
  
• Accepted Supplementary Cementitious Materials (SCMs) include ground granulated blast furnace slag, flyash, silica fume and rice hull ash. Other SCMs may be allowable if they can be shown to have no associated emissions.

The C3 Monitoring and Verification Plan (M&V) describes the two methods for participation in C3, and details the procedures for setting baselines, quantifying carbon offsets and verifying carbon offsets for approved projects.

In the project method, the baseline is determined on a project level with regionally specific data that includes weather data, over-design criteria and regional practice. Offsets are determined by the amount of cement not used below the baseline. Examples of projects include road projects, building projects, large infrastructure projects, etc. In the company method, a baseline amount of Portland cement used per total concrete poured over a previous three year period is established. The offsets are defined as the amount that the ratio of cement to concrete lowers below 5%. See sample calculations.

For both participation methods, the participant signs a Project Participant Contract and a Bill of Sale if the participant is obtaining incentive payments for the offsets. For each project or company, a registration form is completed, which includes all pertinent information about the project or company, sets the baseline and estimates a projected quantification of offsets.

Once the concrete is poured, a verification form is completed which include the offsets achieved by the project or company. In addition to the verification form, the participant provides supplementary documentation which may include mix designs, truck tickets, bills of lading, invoices, and computer printouts of cement/concrete sold. Along with the verification forms, a Certificate of Verified Carbon Dioxide Credits is completed. Once these documents are accepted, the offsets are considered verified and incentive payments, set at $0.50 per metric ton of offsets, are made to the participant. More on program management.