Blast furnace slag, a byproduct of iron-making, qualifies as a supplementary cementitious material in the Cool Climate Concrete program.

Metric tons of avoided emissions translate into offsets at a one-to-one rate (one metric ton of avoided CO2 emissions is equal to one offset). The Climate Trust buys the resulting offsets in exchange for incentive payments of $4 per offset to producers each quarter.

To assist producers, an analytical tool illustrates the link between cement reduction and offset generation. This tool is customized and shared with each producer, and uses its baseline data to evaluate potential offsets and incentives that could be generated at various portland cement reduction levels.

The first portion of the tool provides specific precalculated offset scenarios, and a second portion estimates potential offsets and incentives based on user inputs. A producer can use these tools to explore and establish cement reduction targets.

Documentation is third-party verified, and includes monitoring baseline portland cement use, actual cement reductions, and CO2 emissions avoided. As sustainability becomes increasingly important, it is more advantageous for producers to track and support their sustainability efforts. Quarterly C3 documentation provides tailored, performance-based reports showing actual consumption and production, and can help track progress toward sustainability goals.

The practices that are realized through the C3 program—utilizing industrial byproducts and reducing portland cement use—make it possible for producers to receive benefits while furthering the economic and environmental sustainability goals of the concrete industry.

Lura Schmoyer is the C3program manager and Miranda Intrator is C3program coordinator at West Main Consultants. E-mailschmoyer@wm-consultants.comor

For Example…

The following calculations follow a sample producer through C3 program calculations during the first calendar quarter. Based on quarterly data from the past three years, this sample producer has used an average of 7900 tons (15,808,333 pounds) of portland cement to manufacture an average of 27,000 yards (106,866,667 pounds) of concrete. This yields a baseline cement-to-concrete ratio of 0.1479.

For the current quarter of participation, the sample producer submitted documentation showing it bought 6300 tons (12.6 million pounds) of cement and manufactured about 28,131 yards (112,525,000 pounds) of concrete, giving the company a current cement-to-concrete ratio of 0.1122.

The program calculates baseline and current emissions by multiplying the respective cement-to-concrete ratios by the program's established cement emissions factor of 0.81. This accounts for the amount of CO2 released per metric ton of cement produced.

This calculation yields the effective emissions per yard of concrete, which is then applied to the current amount of concrete manufactured and converted to metric tons (divided by 2204.6), giving total emissions. For the same producer, the baseline emissions are 6115 metric tons and the current emissions are 4630 metric tons.

Avoided emissions are then calculated by subtracting the current emissions from the baseline emissions, and the result is translated to offsets at a one-to-one rate. The offsets generated are then multiplied by the $4 price per offset determining the producer's incentive payment for the quarter. The sample producer would earn $5940 for the 1485 metric tons of avoided emissions.