## 5 Comparative Results and Analysis
### Test case 1
#### Test case 2
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Optimum** & & & & & & & & \\
**Results of** & **AIS [6]** & **TVAC-** & **PSO [9]** & **CSO** & **EMA** & **ICAM** & **HTS** & **GSO** & **GWO** & **RCGA-I** \\
**Generating Units** & & & & & & & & & & \\ \hline P1 (MW) & 50.1325 & 47.3383 & 45.2 & 52.684 & 45.155 & 44.2825 & 45.6188 & 52.8074 & 45.6614 \\ \hline P2 (MW) & 95.5552 & 98.5398 & 98.539 & 98.5398 & 98.5398 & 100.110 & 98.5401 & 98.5398 & 98.5398 \\ \hline P3 (MW) & 110.751 & 112.673 & 112.673 & 112.673 & 112.673 & 112.621 & 112.672 & 112.6735 & 112.6735 \\ \hline P4 (MW) & 208.768 & 209.815 & 209.81 & 209.815 & 209.815 & 209.700 & 209.815 & 209.8158 & 209.8158 \\ \hline P5 (MW) & 98.8 & 92.3718 & 94.183 & 93.8341 & 94.5549 & 94.0105 & 94.1027 & 93.8115 & 93.9960 \\ \hline P6 (MW) & 42 & 40 & 40 & 40 & 40 & 40.0235 & 40.0001 & 40 & 40 \\ \hline H5 (MWth) & 19.4242 & 37.8467 & 27.178 & 29.242 & 29.2388 & 28.262 & 27.6600 & 29.3704 & 28.2842 \\ \hline H6 (MWh) & 77.0777 & 74.9999 & 75 & 75 & 75 & 74.7432 & 74.9987 & 75 & 75 \\ \hline H7 (MWth) & 53.498 & 37.1532 & 47.82 & 45.75 & 45.7612 & 46.9948 & 47.3413 & 29.3704 & 46.7158 \\ \hline Total cost (\$) & 10,355 & 10,100.3 & 10,094.12 & 10,111.07 & 10,107.90 & 10,094.7 & 10,094.26 & 10,111.24 & 10,094.05 \\ \hline CPU time (s) & 5.2956 & 3.48 & 3.09 & 2.06 & 3.47 & 2.01 & 2.4203 & 5.2618 & 3.15 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparative performances of the various optimization techniques for the 7-unit system for the load demand of 600 MW and heat demand of 150 MWth. Table 4 shows the comparative results of the CSO [10], EMA [11], WOA [12], IGA-NCM [13], HBOA [17], HJBSA [18], HTS [34], ETLBOI-PSO [37], and TLBO [44] techniques for a 24-unit problem system. All the algorithms performed well, but the ETLBOI-PSO [37] technique gave a minimum generation cost of 57,758.66 dollars, which is the best out of all the other methods. EMA [11] reported the least computation time. Figure 4 shows the total costs obtained by different optimization techniques for a load and heat demand of 2350 MW and 1250 MWth, respectively. In this case, ETLBOI-PSO [37] gave the best results, whereas HBOA [17] gave the worst  
Test Case 4  
This case study took data from a large system with non-convex fuel costs [10; 11; 18; 29; 30; 31; 36; 37]. These large test system had 48 units (26 power-only units, twelve CHP units, and ten heat-only units). The comparative results of the new heuristic optimization techniques for the power and heat demands of 4700 MW and 2500 MWth, respectively, are shown in Table 5. Compared to all the other techniques, KKO [28] gave minimum cost of $115,422, whereas the QQNLP [29] technique reported a generation cost of $116,993.2, which was the maximum, compared to the other methods. Figure 5 shows the total costs obtained by different optimization techniques for a load and heat demand of 4700 MW and 2500 MWth, respectively. In this case, ETLBOI-PSO [37] gave the best results, whereas QQNLP [29] gave the worst results. Test Case 5  
In this case, a large test system of 84 units was taken into consideration. This test case had 40 generating, 24 cogeneration, and 20 heat-only units [12; 30; 31]. The test results of various optimization techniques for the 84-unit system (5000 MWth and 12,700 MW of heat and power demands, respectively) are shown in Table 6. The MPHS [50] techniques  
Figure 5: Total costs for power and heat demands of 4700 MW and 2500 MWth, respectively.