Dear Monayem Parvej, Soupayan Mitra, Shankha Shubhra Goswami

Reference is made to your article:

An Integrated Approach of AHP and TOPSIS for Optimum Selection of Renewable Energy Source

I have read it and here are my comments:

1- In page 1 you say “The problem of optimum selectionis obtained by application of AHP-TOPSIS hybrid method”

There is no MCDM method that can produce an optimal selection. What they try to do is to find an equilibrium among the different demands, which is called a ‘Compromise solution”

You can only reach in MCDM an optimal solution using Linear Programming, however, this method requires the use of a single objective, while all MCDM treat multiple objectives.

In addition, there is no way to check validity, and consistency is not related with it. Consistency only means that there is a transitivity between all the DM estimates, which, by the way, does not correspond to reality.

2- In page 3 “The parameters chosen are: Capital cost, Energy generation, Tariff cost, Emissions, Efficiency, Maintenance cost and Land requirement”

In my opinion, you can’t determine the best renewable source using only 6 criteria. You should employ many more, for instance, reliability and capacity factor, which refers to the number of hours in a day that an alternative must generate electricity. Solar PV and Wind, depend respectively of sunlight and winds blowing.

3- In page 3 “The relative preferences of each parameter are considered by consulting with relevant sources like power industry and others”

This is as it should be, but not in AHP, where the preferences are by intuition, and thus, arbitrary.

In addition, most of your criteria are interrelated, for instance, capital cost depends on the energy output, or capital cost and energy generation, as you call them. Saaty, creator of AHP specifically said that criteria must be independent, consequently, it appears that you are using the wrong method.

4 – In page 4 “The positive ideal solution is identified with an alternative that has the best values for all considered attributes while the negative ideal solution is identified with an alternative that bears the worst criteria values”

This is inexact. The positive ideal solution is the shortest distance to the ideal solution and the largest distance to the worst solution.

5- You say “Lastly, Sensitivity analysis has been carried out by considering both subjective factors measure and objective factor measure to determine preference of the suppliers”

This is inexact. Sensitivity analysis measures the strength of the best solution when there are variations in some criteria, that affect that solution.

6 - In page 5 you say “Those parameters are very influential and essential for making a decision about the selection of renewable energy resources”

This is absolutely true.

7. Attributes are not the same as criteria. The first, are characteristics of the second.

8 – In page 6 “Wind energy is the best alternative for power generation among the others”

It could be, if it could work continuously 7/24, and therefore you can’t directly compare with hydro, bio and geothermal that can work 7y/24.

In addition, according to literature, PV is generally preferred to wind.

Hope that these comments may help you

Nolberto Munier