## 6 Conclusions  
In this paper, the proposed IALO was applied to find the best generation of available units with an intent to reduce the total generation cost of the whole system. Different studied cases with different types of systems and constraints were implemented for investigating the outstanding efficiency of the IALO over its conventional form. Systems with 10, 15, 20, 30, 60, 80, and 90 units were considered. The used  
Figure 11: Fitness of 100 runs from the ALO and IALO for the system with 80 units, multi fuels, value effects, and a 21,600 MW load.  
Figure 10: Fitness of 100 runs from the ALO and IALO for the system with 90 units, POZ, and a 15,900 MW load.  
comparison criteria comprised the best solution, the search speed, the improvement percentage, and the number of fitness evaluations. After comparing the proposed method with its conventional method and other methods, the advantages and disadvantages of the proposed method can be summarized as follows:  
1. The proposed method can reach better results with faster speed than all compared methods for small-scale and large-scale systems with convex fuel cost functions and not very complicated constraints. In fact, for the system with 10 units and multi fuels, the proposed method could reach the best cost very quickly. Similarly, for 15, 30, 60, and 90-unit systems with POZ constraints and a convex fuel cost function, the proposed method is also superior to other compared methods. However, the outstanding performance cannot be reached for the same 10-unit system but with many complicated constraints and a nonconvex fuel cost function.
2. The proposed method can reach highly stable search ability since most of runs have the same or approximately the same solutions with the best run. This enables the proposed method to reach a very small fluctuation and find a high-quality solution easily.
3. The selection of population size and the number of iterations is simple but the conditions to apply Equations (27)-(29) are not easily determined. We had to try different systems to determine the most appropriate conditions for using these equations. For other problems, the conditions may be different from the 15% and 30% values found in this problem.
4. The proposed method can reach much better results than the ALO even when other conditions, different from 15% and 30%, are executed. So, ALO should be replaced with the proposed method for the ELD problem.  
IALO is suggested as a highly efficient method in power systems, and it can be used to address other problems in wind power plants, solar power plants, and conventional power plants.  
[PERSON] and [PERSON] simulated the results and wrote the paper. [PERSON] supported the proposed IALO method. [PERSON] and [PERSON] were responsible for writing and editing. All authors have read and agreed to the published version of the manuscript.  
This research is funded by Funds for Science and Technology Development of the University of Danang, under project B2019-DN01-19 and was supported by the Operational Programme Human Capital of the Ministry of European Funds through the financial agreement 51675/09.07.2019, SMIS code 125125.  
The authors declare no conflicts of interest regarding the publication of this paper.