The Value of Sector Coupling for the Development of Offshore Power Grids

Round 1

Reviewer 1 Report

lines 43-45 please explain the flexibility of the energy system

lines 56-58 please rephrase , is not clear the influence of the sector coupling

lines 99-101 please give explanations to the optimization challenging

lines 214-216 please explaind why is assumed that EVs are not connected to the grid during most working hours - Fig 3  (most of them are charged Solar photovoltaic by day) 

lines 229 - 233 please explain more clear  the effects of H2 in the model and of the biomass 

lines 289-292 please explain how did you choose the wind capacity potential of the three steps 

lines 332-334 please explain fig 9 , left and right graphical presentations 

lines 335-336 please give details why CF depends of the installed capacity - Fig 10 

lines 391-393 please explain the aggregated technologies investigated in the paper

lines 418-420 please give more explanations about the results in Fig 12

lines 424 - 425 please explain what represent the Interconections and their measure units 

 lines 446-449 please explain the emmisions results in the different scenarios 

table 5  - please explain the information about "the relative change with respect to total system cost %

Author Response

We thank the reviewer for his/her comments and effort. We have now addressed his/her comments below:

• lines 43-45 please explain the flexibility of the energy system

We have now clarified this issue in the text.

• lines 56-58 please rephrase , is not clear the influence of the sector coupling

We have now provided further explanations about this in the text.

• lines 99-101 please give explanations to the optimization challenging

We have now clarified this issue in the text.

• lines 214-216 please explained why is assumed that EVs are not connected to the grid during most working hours - Fig 3  (most of them are charged Solar photovoltaic by day) 

We have now clarified this issue in the text. Our assumption in the model is that chargers will only be available at home, and not in working places. Therefore, in the middle of the day it is not possible to charge/discharge the EVs.

• lines 229 - 233 please explain more clear  the effects of H2 in the model and of the biomass 

We have now provided additional information about this in the text.

• lines 289-292 please explain how did you choose the wind capacity potential of the three steps 

We have now written a few more lines to explain this.

• lines 332-334 please explain fig 9 , left and right graphical presentations 

We have now provided further explanations in the text about this.

• lines 335-336 please give details why CF depends of the installed capacity - Fig 10 

We have now provided more detail about this in the text.

• lines 391-393 please explain the aggregated technologies investigated in the paper

We have removed "VRE" and replaced it with specific technologies that we refer, i.e. solar PV, onshore wind, and offshore wind (both radially connected and hub connected)

• lines 418-420 please give more explanations about the results in Fig 12

We have now provided more detail in the text about this and we have added an additional figure to help illustrate our explanation.

• lines 424 - 425 please explain what represent the Interconections and their measure units 

We have now explained this in more detail in the text.

• lines 446-449 please explain the emissions results in the different scenarios 

We have now provided additional information in the text about the results of the different scenarios.

• table 5  - please explain the information about "the relative change with respect to total system cost %

We have added extra information in the caption of the table.

Reviewer 2 Report

The abstract is good. However, it could present more information about what was done in the research. 

The introduction introduces the reader to the issue. The chapter presents the literature review. It is thorough. The whole bibliography consists of 63 publications. A significant part, as many as 13, are author publications. However, it is understandable, because of the problematic of the article.

Section 2 describes the energy system model (modelled in Balmoreli). The data for the model are presented. This part of the article is very extensive. However, the authors present only the theoretical issues of the model. The mathematical part is not shown. Part 3 describes the coupling scenarios of the electricity, thermal power and transport sectors. Section 4 presents and analyses the results. Section 5 discusses the results and Section 6 presents the conclusions.

The article reads very well. I found it interesting. Apart from the lack of presentation of mathematical solutions, I think it is suitable for publication without amendments.

Author Response

We appreciate the comments from the reviewer and thank him/her for his/her time.

We acknowledge that there is a significant part of publications in the bibliography with author publications. However, most of these publications provide additional information as well as mathematical formulations regarding the methodology, that we believe it could be of relevance for future readers of the paper. Thanks to your comment we have realized that reference 25 was not correct. We have now corrected this issue with the final published paper.

Reviewer 3 Report

The manuscript was about the The value of sector coupling for the development of offshore power grids. The justification of the work and the research gap is clearly stated. Methodology is well described. Results and discussion are clear and explanations are substantiated. Thus, the manuscript could be interesting to the readers. 

Author Response

We appreciate the comments from the reviewer and thank him/her for his/her time.

Reviewer 4 Report

The paper analyses the influence of sector coupling on the development of offshore grids. It performs least-cost optimization
of capacity development and operation of the energy system with varying levels of sector coupling of the European North Sea region towards 2050 from a socio-economic perspective. The modelling integrates the potential increase of wake losses with the size of hub connected wind farm development in detail. The Balmorel energy-system model is used. The findings are in correlations with those in literature.

The paper is original, well structered and complete. The bibliography is adequate.

Author Response

We appreciate the comments from the reviewer and thank him/her for his/her time.

Round 2

Reviewer 1 Report

please explain Fig 2

lines 105-107 please rephrase , is not clear the information

lines 113-117 please give references

lines 120-122 please correct the grammar and expressions

lines 132-135 please explain , is not clear the information

lines 141-145 please check the english

lines 164-144 please check the english 

lines 167-174 please rephrase, is not clear the information and check the english

please organise better the table 10 , is not clear the information on each row 

lines 179-184 please rephrase and check the english

lines 198-200 please rephrase with care for english expressions

please explain Eq 1

lines 379- 382 please explain , is not clear the information

lines 469-471 please rephrase, english needs improvement

please explain Fig 8 

lines 481-484 please explain how did you obtained the saving results /how  did  you compute them  

lines 516-520 please rephrase, is not clear

lines 521-524 please rephrase , is not clear 

lines 526 -527 and table 2 : define please , is it quartiles or quintiles?

please explain Fig 12

lines 560-566 please explain how did you obtained the saving results /how  did  you compute them  

lines 617 and tables 4, 5, 6 : define please , is it quartiles or quintiles?

lines 641-645, equation 32 and lines 651-655 : check please the notations TC/ CT

lines  672-679 please explain how did you obtained the saving results /how  did  you compute them  

 

Author Response

We appreciate the effort and time of the reviewer. 

However, we believe there has been some sort of error in this second report. Hereby some examples:

-There are some comments that seem to be part of another paper. For example:

• lines 617 and tables 4, 5, 6 : define please , is it quartiles or quintiles?
• lines 641-645, equation 32 and lines 651-655 : check please the notations TC/ CT
• lines  672-679 please explain how did you obtained the saving results /how  did  you compute them  

All the mentioned lines are part of the reference section, there is only 5 tables in the paper, etc.

-In the first report, the English language and style was categorized as "English language and style are fine/minor spell check required", but in this new report, where few changes have been made, it is categorized as "Moderate English changes required".

We kindly ask the reviewer to have a look at his/her comments and provide some clarification so we can address them properly. We also kindly ask the reviewer to let us know whether the comments refer to the version with marked changes or the one without marked changes.

Thank you so much.

Round 3

Reviewer 1 Report

the paper can be published