 |
Sample Calculations:
Project method
| A |
B |
C |
D |
E |
F |
G |
H |
I |
| Design Mix |
Strength psi |
Quantity poured for project (cy) |
GGBFS in project mix design (lbs/cy) |
Portland Cement in project mix design (lbs/cy) |
Portland Cement in project mix design (lbs) |
Baseline Portland Cement (lbs/cy) |
Baseline Portland Cement (lbs) |
Metric Tons Offset |
| #1 |
4,000 |
572 |
300 |
300 |
171,600 |
600 |
343,200 |
73.93 |
| #2 |
4,000 |
2,532 |
210 |
390 |
987,480 |
600 |
1,519,200 |
229.09 |
| #3 |
4,000 |
860 |
150 |
450 |
387,000 |
650 |
559,000 |
74.10 |
| #4 |
4,000 |
21 |
60 |
540 |
11,502 |
650 |
13,845 |
1.01 |
| #5 |
3,000 |
682 |
260 |
260 |
177,320 |
500 |
341,000 |
70.52 |
| #6 |
4,000 |
795 |
360 |
240 |
190,800 |
600 |
477,000 |
123.31 |
| |
|
|
|
|
|
|
|
|
| Total |
|
5,462 |
|
|
1,925,702 |
|
3,253,245 |
571.96 |
The reduction in Portland cement is calculated based on the Portland
cement not used in the project due to C3.
As seen above, a baseline is established for each mix design (Column
G) based on the weight of Portland cement per cubic yard of concrete
that would have been used if the project was not part of C3.
The baseline is multiplied by the quantity of concrete poured for
the project (Column C) to get the total baseline weight of Portland
cement for each mix (Column H). The actual total weight of Portland
cement used in each mix (Column F) is then compared to the baseline
to determine the reduction in Portland cement for each mix. So, in
the example above, the reduction in Portland cement for all mixes
is 1,327,543 lbs (3,253,245 – 1,925,702). This weight is converted
to metric tons by dividing by 2,205 lbs./metric ton to get 602.06
metric tons of Portland cement reduction.
The final step to convert the metric tons of Portland cement reduction
to metric tons of carbon dioxide offset. In C3,
it is assumed that every metric ton of Portland cement clinker represents
a metric ton of CO2. Since cement clinker
represents 95% of a typical metric ton of Portland cement, every
metric ton of Portland cement reduction is assumed to reduce CO2 emissions
by .95 metric tons. So, 602.06 is multiplied by 0.95 to get 571.96
metric tons of offsets for the project.
Company method
| Baseline Values |
| Quarter |
Amount of cement
used (lbs.) |
Amount of concrete
manufactured (lbs.) |
Ratio |
| Quarter One |
443,000 |
2,950,000 |
0.150 |
| Quarter Two |
460,000 |
3,150,000 |
0.146 |
| Quarter Three |
343,000 |
2,420,000 |
0.142 |
| Quarter Four |
312,000 |
2,260,000 |
0.138 |
| Actual Amounts During One Year of C3 Participation |
| Quarter |
Amount of cement
used (lbs.) |
Amount of concrete
manufactured (lbs.) |
Ratio |
Metric Tons
Offset |
| Quarter One |
348,000 |
2,827,000 |
0.123 |
32.89 |
| Quarter Two |
375,000 |
3,225,000 |
0.116 |
41.68 |
| Quarter Three |
425,000 |
3,420,000 |
0.124 |
25.05 |
| Quarter Four |
254,000 |
2,240,000 |
0.113 |
24.13 |
The reduction in Portland cement is calculated based on the Portland
cement not used over the quarter by the company due to C3.
A baseline is established based on the ratio of Portland cement used
to the total amount of concrete manufactured. The baseline is based
on data from three prior years; quarterly baselines are established
by averaging the three years of data for each quarter. At the end
of each quarter of company participation, the ratio of Portland cement
to concrete manufactured is determined. The actual ratio is then
subtracted from the corresponding quarter’s baseline ratio
and multiplied by the concrete manufactured during the quarter to
determine the reduction in Portland cement. In the example above,
this would be (0.150 – 0.123) multiplied by 2,827,000, which
equals 76,329 lbs of Portland cement. Converting this to metric tons,
there
is
a 34.62
metric ton reduction of Portland cement use.
The final step to convert the metric tons of Portland cement reduction
to metric tons of carbon dioxide offset. In C3,
it is assumed that every metric ton of Portland cement clinker represents
a metric ton of CO2. Since cement clinker
represents 95% of a typical metric ton of Portland cement, every
metric ton of Portland cement reduction is assumed to reduce CO2 emissions
by .95 metric tons. So, 34.62 is multiplied by 0.95 to get 32.89
metric tons of offsets for the quarter.
|
 |
Program
Details
Sample
Calculation