Page 284 - Biofuels for a More Sustainable Future

Life-cycle costing: Analysis of biofuel production systems 249

Table 8.6 The estimated coefficients and P-values: LCC of jatropha biodiesel
Term Estimate t Ratio Prob>|t|
Operating rate 0.0009815 <.0001 †
Feedstock price 0.001047 <.0001 †
Capacity –0.001364 <.0001 †
Interest rate 2.7154324 <.0001 †
Biodiesel conversion efficiency –0.499616 <.0001 †
(Capacity-75)*(Capacity-75) 1.8646e-5 <.0001 †
(Interest rate-0.04)*(Operating rate-295) 0.0037701 <.0001 †
(Biodiesel conversion efficiency- –0.001009 <.0001 †
0.94)*(Feedstock price-450)
(Feedstock price-450)*(Interest rate-0.04) 0.0034463 <.0001 †
(Biodiesel conversion efficiency-0.94)*(Interest –1.430167 0.1245
rate-0.04)
(Feedstock price-450)*(Feedstock price-450) –2.308e-7 0.1781
(Capacity-75)*(Interest rate-0.04) –0.001528 0.3109
(Interest rate-0.04)*(Interest rate-0.04) 3.4349643 0.3975
(Biodiesel conversion efficiency-0.94)*(Biodiesel 0.2010329 0.4580
conversion efficiency-0.94)
(Biodiesel conversion efficiency- 3.4984e-5 0.6901
0.94)*(Operating rate-295)
(Capacity-75)*(Operating rate-295) –4.377e-8 0.7605
(Operating rate-295)*(Operating rate-295) 8.7365e-9 0.8055
(Feedstock price-450)*(Capacity-75) 7.1853e-8 0.8095
(Feedstock price-450)*(Operating rate-295) –1.053e-8 0.8749
(Biodiesel conversion efficiency-0.94)*(Capacity- –0.000018 0.9606
75)
† Significant at a 95% degree of confidence.

Similarly, the LCC of fish oil and waste cooking oil biodiesel have a set of
statistically significant interactions identical to that of jatropha oil biodiesel.
The t-ratios of these interactions are of small magnitude like those of
observed in the jatropha biodiesel sensitivity analysis but the order of their
relative magnitudes is different.
The second-order regression equations that arise from the DOE analysis
are captured in Eqs. (8.13), (8.14). The variables X 1 ,…, X 5 are defined in the
same manner as Eq. (8.12).

C FO-biodiesel ¼ 0:398 0:2773X 1 +0:00104X 2 0:00136X 3 +1:952X 4
ð
ð
+0:00098X 5 0:00109 X 1 0:94Þ X 2 250Þ
5 2
ð
ð
+1:836 10 ð X 3 75Þ +0:0037 X 2 250Þ X 4 0:04Þ
+0:0034 X 4 0:04ð Þ X 5 295Þ
ð
(8.13)