Dear Federico Gabriel Camargo

I have read your paper:

Fuzzy multi-objective optimization of the energy transition towards renewable energies with a mixed methodology

My comments:

1- In page 1 you say “Energy transitions are necessary to obtain a better systemic EROI”

Energy transitions are needed to reduce global warming, not only to get a better return

I agree with you with the word ‘systemic’, that is, considering the whole scenario as a system, something that not many people recognize, and continue doing evaluations on independent sources of generation

“Second, formulating these problems requires expensive and complex software’

I agree that you need complex software but not necessarily expensive. SIMUS is free and can do the job.

We should not be looking for ‘market equilibrium’ as you say, we should be holistically looking for economics, technical, environment, society, public health and sustainability

2- On page 2 “This problem is complex and it cannot be solved satisfactorily using linear or dynamic programming methods due to the number of objectives”

I disagree. Have you tried using Linear Programming? I did, and it works. The number of objectives is not important, you can use as many as wished.

To consider risk you don’t need fuzzy.

3- In page 3 “The simultaneous satisfaction of these criteria is difficult and arises from applying compromise solutions between them (optimization) and according to the needs (hierarchy)”

Compromise solution is exactly the opposite as you say. You can’t ask for optimality in MCDM, because normally it is impossible maximize benefits and at the same time minimize costs, and this is the reason for compromise (defined by Zeleny in 1974).

By the way, the AHP hierarchy is not applied here where there is not a lineal hierarchy, but a network defined by interconnections in every sense. In my opinion it is impossible to use this elemental method in a problem of this nature.

4- Page 5 “Those models that are only deterministic and probabilistic (not fuzzy) do not take into account value uncertainties”

You can consider uncertainties without fuzzy, therefore, what you say is inexact.

“There is also no agreement on how to assess and prioritize environmental variables”

Sorry, this is inexact. The only thing you need to do is to establish maximum allowable limits of contamination, something you can’t do with AHP or TOPSIS. Try PROMETHEE.

5- “From these results, it is observed that the most convenient source is nuclear”

Obviously, because you did not consider the externalities of nuclear fission. That is, you did not add as a maintenance cost the tremendous cost of keeping the spent uranium rods during hundreds of years, nor the great risk that nuclear reactors entail. Did you forget Chernobyl, Three Miles Island and Fukushima? The probabilities are low (3 accidents in 400 reactors in the world), but the consequences can be catastrophic. Could you imagine what would happen if the Zaporizhzhia nuclear plant in Ukraine the largest in Europa, is attacked and destroyed?

6- Page 12 “Each of these scenarios were optimized using the methodology proposed in this article. The most satisfactory scenario was obtained based on the best of the six scenarios based on each renewable source”

It appears that you forgot that this is a system, and as that, you can’t compute each part separately, and then adding them up. Basic concept in Systems Engineering.

7 – Page 14 “Additionally, in this scenario the best EROI was obtained by building nuclear generators”

Expected, because maintenance cost of spent rods is ignored. Very convenient indeed!

Are you sure that Biomass has security of supply? How? Logging forests?

8- “that is, the systemic EROI could grow by 50% if only nuclear power plants were installed and all other generation sources were dismantled”

I hope mot. This would be a disaster!

9- “It would not be possible to easily solve this problem with mathematical programming techniques”

This is your opinion, and you put it as an unquestionable truth. I suggested a procedure to solve the transition problem for 2035 and 2050, and it is by bar more complex than yours, and it is published. You put fuzzy everywhere, as if it were the Holy Garial, and in my humble opinion, fuzzy has no room in this problem.

10- page 17 “he fact that the search space is continuous requires that it be discretized or transformed into another simpler search space for these alternatives to be valid. This can cause good solutions to be lost.”

I am afraid you are mistaken. In a correct MCDM model you should be able to add as many new alternatives as you want. For instance, why don’t you consider Hydrogen Cells or Nuclear Fusion?

The first is already in the market, in portable units of about 1 MW. The second is under construction in Europe, and scheduled to be tested in 2024.

“This makes the optimal solution up to the decision maker.”

I can’t believe I am reading this. If the DM is the miracle man that decides about something so important, why to bother with MCDM?

“it only the weights produced by the AHP”

Therefore, criteria importance is decided by intuition? Is that science?

I am only reviewing your paper; I don’t judge it, but I am in complete disagreement with the method you propose.

I hope my comments can help.

If you want to discuss in Spanish over the phone, here is my WhatsApp:

+1 613 770 71213 (Canada) One hour difference with Argentina

Nolberto Munier