Dear Priyanka Majumdera, Amrit Das, Ibrahim M. Hezam Al-Mishnanah, Darko Božanić

I have read your article:

“Integrated BWM-TOPSIS-I Approach to Determine the Ranking of Alternatives and Application of Sustainability Analysis of Renewable Energy”

Here are my comments:

1- In page 2 you say “MCDM is used in this study to determine which RESs more reliable”

I believe that this is incorrect, for MCDM is used to select the most convenient alternative, subject to a set of criteria, reliability being one of them. In addition, your title calls for sustainability, and therefore, what must be sought is the more convenient alternative from the economics, social and environmental point of view, and all of them considered together.

2- In page 3 you say “Fossil-fuel-powered power plants emit half as much CO2 as natural-gas-powered ones”

True, but also you should say than extraction of natural gas results in a leakage of methane which is 34 times stronger than CO2 in trapping heat.

3- In page 3 you mention TOPSIS-I, but never explained what it is.

4- In page 5 you say “Based on four primary criteria, economic viability, including social acceptance, environmental viability, and commercial viability, the use of MCDM and fuzzy-analytical hierarchical approaches in this context was studied”

Unfortunatelly, you forgot to add ‘Technical issues’, a fundament criterion, because not all sources of renewable energy have the same load factors time-wise. Fossil fuel powered power plants, as well as nuclear can work’ 7/24 at constant output, but Photovoltaic (PV) as maximum can work, depending on sun irradiation, from about 9 in the morning to 17 hours in the afternoon, depending on the latitude. Solar, that is, using solar dishes can work from 9 in the morning to 24 hour or mid night, and of course, wind energy is aleatory, by depending on the intensity of winds. This is the great drawback of these energy sources.

All of the four main criteria you mention are interconnected, therefore, they are not in a lineal hierarchy, and your Figure 2 does not represent reality.

5- In page 6 you say “In terms of energy generation, viability, and maintenance, solar energy collection is now the most useful in the transportation infrastructure”

I wonder where is the relationship between solar energy, in both PV and solar thermal, related with viability and maintenance, with transportation structure.

6- In page 6 you say “For ranking the EU nations based on their sustainable energy development, this study used the SWARATOPSIS framework based on Pythagorean fuzzy sets [23]”.

In my opinion, I don’t see how a complex problem like this involving EU nations can be treated by a method like SWARA, based on subjectivities, although I think that TOPSIS is able to do the job.

What is the ‘IF-TOPSIS’ method? You don’t explain it.

What is a ‘supreme metric’? The reader does not have the obligation to be familiar with them.

7- In page 8 you say “Choose the criteria that are of the greatest relevance (the best) and importance (the worst)”

Fine, based on what?

8 – On page 9 the articles talk of consistency. Fine, consistency of agreement between the experts and find or adjust the CR in such a way that the matrix is consistent, or that there is transitivity.

However, where is the relation with reality? Is there any law, axiom or theorem that supports that transference? Does it mean that because the matrix MUST BE transitive, the real world MUST ALSO BE TRANSITIVE? It appears that we are adjusting reality to our convenience, or it subject to our wishes.

9- Table 3. It was built to explain the alternatives and criteria, which is good. However, in some cases, in the 17 rows that link criteria and alternatives, the explanation is not related with the factor. For instance, in ‘Land requirement’; normally, in this type of projects it refers to the physical area used by any different types of generation plant. The explanation does not make any mention about land use, instead is refers to a sustainable energy system.

“A sustainable energy system requires a balance between economic growth, environmental protection, and energy security. A key component of this is energy systems, which are based on the three key principles of energy security, social equality, and environmental protection.”

As seen, not relation with the factor. The same happens in another rows, for instance in factor ‘Diesel” where says “Contributes to climate actionand environmental stewardship by reducing greenhouse gas emissions, shrinking our water footprint, and increasing reuse and recycling rates”.

Where is the relationship with Diesel engines?

Contributes to water footprint, and increasing reuse and recycling rates. Could you explain this?

Where is water footprint linked with Diesel and recycling issues?

10- In page 15 you say “some sophisticated techniques, such as AHP [28], TOPSIS [48], AHP-TOPSIS-I [31], and BWM-TOPSIS [49].”

These are not sophisticated techniques, quite the opposite, they are the simplest, specially AHP.

In my opinion sophisticated techniques are ANP, ELECTRE, PROMETHEE. Linear Programming, Goal Programming, SIMUS.

11- In page 15 you say “The BWM approach is efficient for criterion selection, which is why this advanced approach may be well-versed”

In my opinion, a method based on arbitrary selection of which is the best and the worst criteria can’t be called ‘efficient’. The adjective ‘well-verse’ according to the Dictionary means: “having a lot of knowledge about something”.

Where is the lot of knowledge in MWM? Suppose that a project involved selection and sale of different products; on what authority the DM can say that Price is more important than Demand or vice versa? Remember that the two criteria have a non-linear relationship; it could be that a reduction in price produces and increase in demand, but can the company increase its production? Perhaps not, due to restrictions in capital or capacity, therefore, it does not make too much sense to assume that one criterion is more important than another, without considering all the other criteria at the same time. This problem is common to all MCDM using pair-wise comparisons.

12- Table 11 shows that the best alternative is gas, as this is constant in all the other methods used.

Curiously, real-world shows that this is not true. Countless studies show that the most promising alternative is PV and Wind. Of course, green natural gas is also very important. Look at what the Interstate Natural Gas Association of America (Verbatim) say:

“[Natural gas] has a valuable role to play as a complement to renewables, matching up very well as a backstop to their inherent intermittency.”

Don Santa, president and CEO of the Interstate Natural Gas Association of America

In point 2 I mentioned drawbacks of natural gas, that obviously you did not consider in your paper.

Where is wind energy in your Table, when you can check that in any country you go there are wind farms?

13- In page 17 you say “This study has given birth to hybrid decision making which can be made use of in order to determine the ranking of alternatives”

This incorrect. You developed your paper in 2022, without considering that maybe 15 years before, there were hybrid MCDM methods.

I hope my comments may be useful to you, they are only my opinions, since I am not judging; you can extract your own conclusions.

Regards

Nolberto Munier