Review Reports - Performance Analysis of a PEMFC-Based Grid-Connected Distributed Generation System

Round 1

Reviewer 1 Report

1. The literature needs to be improved with latest and relevant articles.

2. The authors mentioned that the research addresses the unit sizing of PEMFC based grid connected DG. But the information related to this topic is found no where in the manuscript.

3. The image resolution needs to be improved.

4. Is there any possibility that the performance metrics can be compared under steady state and transient operating conditions.

5. "The PEMFC based grid-connected DG system at Marmara University, Faculty of Technology was analyzed in detail in this study. 53.53% of the total energy demand is met by the utility grid, while 46.47% of the demand is met by the DG system". The process for achieving this conclusion needs to be explained with more detail.

Author Response

At first, we would like to extend our special thanks to you to contribute to our paper by reviewing with your valuable comments.

Comments and Answers

No general comments, just points.

Point 1: The literature needs to be improved with latest and relevant articles.

Response 1: Thanks for your constructive comment. We tried to update the Intro part and narrate well based on the relevant literature. We added some useful explanations as follows:

“In [7], the authors presented the design and implementation of a microgrid labor-atory for teaching laboratory that its structure is presented of a wind turbine, PV, bat-tery bank, DC/DC and DC/AC converters for dispatching the energy from sources and utility grid to the load side. Apart from this approach, [8] proposes the implementation of a single-controllable DG structure in the engineering school of the Federal Universi-ty of Minas Gerais using commercial devices. Also, a virtual laboratory is presented with the objectives of scalability, interaction, maintainability, and fast response time for a microgrid structure renewable energy sources [9].”

Point 2: The authors mentioned that the research addresses the unit sizing of PEMFC based grid connected DG. But the information related to this topic is found no where in the manuscript.

Response 2: Thank you for your attention. As known, a unit sizing problem can be solved by any optimization approach and we did not present any unit sizing solution in this paper. We removed it accordingly.

Point 3: The image resolution needs to be improved.

Response 3: Thank you for your valuable comment. We checked all figures to get an improvement in resolution.

Point 4: Is there any possibility that the performance metrics can be compared under steady state and transient operating conditions..

Response 4: Thank you for your attention. All of the results and analysis were already realized entirely under transient and steady-state conditions.

Point 5: "The PEMFC based grid-connected DG system at Marmara University, Faculty of Technology was analyzed in detail in this study. 53.53% of the total energy demand is met by the utility grid, while 46.47% of the demand is met by the DG system". The process for achieving this conclusion needs to be explained with more detail.

Response 5: Thanks for your valuable comment. We tried to define and elaborate this issue as follows:

“As seen in Table 4, the annual average energy demand is calculated as 3791.04 kWh and also 2029.497 kWh of energy which cannot be met by production can be supplied from the grid via the hybrid inverter. The remaining energy demand is met by the distributed generation that denotes 1761.543 kWh. To this end, we can clarify that 53.53% of the total energy demand is met by the utility grid, while 46.47% of the demand is met by the DG system. ”

Author Response File: Author Response.docx

Reviewer 2 Report

The article presented is very interesting and touches on the problem of cooperation between different generation sources. The topic is not new, as evidenced by the references to other projects of this type presented in the initial part of the publication.

In the introduction, the article's contribution should have been more strongly emphasized. In addition, I did not notice in this article a clearly posed scientific problem, the solution of which the authors are trying to seek. It seems to me that this is the biggest shortcoming of the presented work, which absolutely must be reviewed.

The rest of the article is correct, and I have no significant comments except those listed below:

1) Is the curve shown in Figure 7 from mathematical analysis (that's what it looks like and that's what it says) or from measurements? Unfortunately, but wind sources of several hundred watts very often do not maintain the parameters stated in their documentation. Do the authors have any experience in this matter?

2) Figure 19 needs modification - no axes, descriptions, etc. Also, this is not a "pie chart".

3) The authors do not mention further work with the built system. It is difficult to imagine that this type of installation was built solely for the purpose of carrying out research for the article presented.

Author Response

At first, we would like to extend our special thanks to you to contribute to our paper by reviewing with your valuable comments.

Comments and Answers

The rest of the article is correct, and I have no significant comments except those listed below:

Point 1: Is the curve shown in Figure 7 from mathematical analysis (that's what it looks like and that's what it says) or from measurements? Unfortunately, but wind sources of several hundred watts very often do not maintain the parameters stated in their documentation. Do the authors have any experience in this matter?

Response 1: Thanks for your attention. Yes, as you mentioned, several hundred watts do not often maintain; however, we plotted this Figure. 7 based on Table 2. According to the Weibull calculations, the wind turbine power curve can be expressed in Fig. 7. The total annual obtained energy from the wind turbine is calculated as 228.493 kWh as seen in Table 2.

Point 2: Figure 19 needs modification - no axes, descriptions, etc. Also, this is not a "pie chart".

Response 2: Thanks a lot for your correction. Axes for horizontal description were added as “ Variety of Total Energy Demand Met by” and for the vertical description “Percentage of Energy” did.

Point 3: The authors do not mention further work with the built system. It is difficult to imagine that this type of installation was built solely for the purpose of carrying out research for the article presented.

Response 3: Thanks for your contructive comments. We tried to update the Intro part and narrate well with further works based on the relevant literature. We added some useful explanations as follows:

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Dear Authors,

thank you for considering my observations. They seem to have positively influenced the quality of your article and it is now suitable for publication.

I wish you all the best!