Energy Sector Development: System Dynamics Analysis

If the Figure 2 is adopted/reproduced from ref [22], please send the copyright permission you have obtained.

Thank you for this observation. This Figure is taken from our own research paper entitled: “A Systems-Thinking Approach to Address Sustainability Challenges to the Energy Sector”. We confirm that the Figure is designed by our research team.

1.1

First of all, it is an interesting paper which presents an application of system dynamics to analyse the Australian energy sector.

Thank you for the encouraging comment.

1.2

Although authors present the contribution of a system dynamic approach for examining the behavior of the energy sector and why a system dynamic model is an effective management tool, I think that author should provide more details about energy sector in order that reader can understand the challenges and complexity of energy sector. In addition, a more detailed discussion on system dynamics is necessary.

Thank you for this observation and suggestion. We have now provided details about the energy sector challenges. In addition, we have added additional text that describes how the system dynamics is necessary.

Page 1; lines 40-43

Page 2; lines 55-58

1.3

In my view section 3.1 could be a part of section 2.1 because this section presents the CLD and the SFM. Also, section 2.2 could be integrated into section 3.2.

Thank you for your suggestion. If the editor does not mind having long sections we will do that.

1.4

It is not clear how the results from sensitivity analysis lead authors to select the three scenarios. Which was the criterion for the selection of these scenarios?

Thank you for pointing out this. We have amended the manuscript to better explanation how the results from sensitivity analysis can be used to develop three development scenarios for Australian energy sector.

The updated text:

“Three possible scenarios for energy development in Australia were identified. These scenarios were: (1) a no growth scenario, (2) a base case scenario, and (3) a likely to happen scenario as described in Table 1. These scenarios were identified based on the results of a sensitivity analysis. The sensitivity analysis was done by adjusting model parameters by ± 20% to identify the most influential parameters in energy production capacity. The most influential parameter was the gross demand growth rate” parameter.

Page 6; lines 203-208

1.5

Authors have to reconsider the importance of the graphs regarding the behavioral tests and extreme condition tests. Also the discussion on the results from scenarios is poor. It is the main goal of this paper, so I think that authors have to provide more details on each scenario and the behavior of the energy sector system based on the figures 10 and 11.

Behavioural tests are important to show the robustness and reliability of the model, and thus achieve the first aim of the study, which is “to formulate and validate a system dynamics model of the energy sector”, and thus gives more confidence in the obtained results.

Regarding the scenarios, as we cover a complex system (the energy sector) with 7 types of primary energies (black coal, brown coal, gas, wind, solar power, hydro power, and bio power), we thought summarizing scenarios and their results in Table 1 and Table 2, and focusing on the current scenario and implications in the discussion (with considering the other scenarios) would make it easier for the reader. Figures 10 and 11 are for black coal and wind as examples, one for fossil fuel and one for renewables. If we added the rest of the graphs of other energies and discussed in each scenario in detail, the reader would be overwhelmed by graphs and details. So, we sought to make it clearer and easier for the reader as much as possible.

2.1

This is an interesting and well-written article

Thank you for the encouraging comment.

2.2

Some interested readers may not know what GWh stands for. I suggest that a definition is given where the unit first appears (line 88).

Thank you for this observation. A definition of GWh has been provided where the unit first appeared.

The updated text:

“The different forms of energy were put into the same units, Gigawatt-Hour (GWh), one gigawatt is one billion watts. It is a unit that represents the energy used or the energy production capacity, and we used it to express all energy resources. This is used by many sources and it is the scientific way to compare and summarize energies [23]”.

Page 4; lines 120-123

2.3

The authors use both “systems dynamics” and “system dynamics”. They ought to stick with one of them

Thank you for this observation. “Systems dynamics” in line 67 has been corrected to “system dynamics”.

Page 2; line 67

2.4

Reference is made to Laimon et al. [22] in a few places. This is apparently a manuscript that has been submitted for publication, but has not yet been accepted.  Many journals do not permit the inclusion of submitted papers in a list of references.  You should check with this journal about the proper procedure.

Unpublished work has a description in “Applied sciences”. Point 4 (Unpublished work, submitted work, personal communication), to which we adhered.

https://www.mdpi.com/journal/applsci/instructions#references

However, the current paper is a stand-alone article, as it represents the quantitative method and has its own data. In addition, reference [22] is our work.

2.5

The language and grammar are excellent in this paper.  I did notice one error on line 77 (over time in two words instead of one).

Thank you. This has been corrected to “over time”.

Page 2; line 85

2.6

You refer to the curves in Figs. 7-9 as S-shaped growth curves. This does not seem to me to be the proper term to use.  You may simply want to drop the term “S-shaped”.

The term “S-shaped” (line 286) has been dropped as suggested, and the paragraph has been rewritten.

The updated text:

“The extreme condition test results (Figs. 7, 8, and 9) show that the pattern of modelled behaviour did not dramatically change…”

Page 11; lines 297-298

2.7

In Figs. 10(c) and 10(e), the keys or identifications for the different colors given below the graphs do not match the curves in the graphs. For example, Fig. 10(c) identifies 6 different colors below the graph, but only three different colors are used for the curves.  The same applies to Fig. 10(e).

Indeed, they are 6 colours. Blue and red for black coal. Yellow and orange for gas. Green and purple for brown coal. Red and orange hardly appear as they represent the energy production “without bankruptcy”. In other words, “with bankruptcy” and “without bankruptcy” are nearly equal, that implies that capacity bankruptcy has no effect in the case of black coal and gas. “We found the effect of bankruptcy is not considerable in black coal and gas (Fig. 10c, and Fig. 11c)”. (Lines 388-389).

Regarding the brown coal, the green colour cannot be seen, which can be attributed to the drawing scale. Black coal and gas production capacities are in millions, 4 and 1.3 m GWh respectively, while brown coal production capacity is in thousands, only 170k at scenario 1. The same in Fig. 10 (e), coal reserves are huge (more than 500 m GWh), while gas reserves are much less (less than 40 m GWh).

However, these results are clarified in Table 2 (reserves column) and discussion.

2.8

In Table 2, I suggest that you add “year” to the first line in front of 2030, 2050, etc. and above “Scenario 1”.

A “year” has been added to the first line as suggested.

Page 16; line 355

2.9

You ought to define what RE stands for (e.g., line 355).

Now, this is defined where it first appeared.

Page 1; line 43

2.10

You present the prices $93/MWh, $68, and $71/MWh on lines 364-366.  You should identify the source of those data.

The source is the same fig. (Fig 11 b). This has been rewritten to clarify it more.

The updated text:

“If wind and solar are available on demand with a backup power the wholesale price will be around $93/MWh by 2030 (Fig. 11b). Other dispatchable RE resources (hydro power and bio power) will be $68 and $71/MWh respectively”.

Page 17; line 385-386

2.11

Under the list of References, you use et al. in a number of places rather than the complete set of authors.  In the text, it is perfectly proper to use et al. such as Ciscar et al. [13], but in the Reference list you should identify all authors or co-authors.  See also references 15, 16, 18, and 29.

Thank you for this observation, and we totally agree. I used EndNote X8.1 reference management software, and this is done by the software not manually, when we chose “numbered” style. Only reference (1) was done manually to show the co-others. However, I’ll keep all references as shown by EndNote X8 (numbered style), unless the editor has another opinion.

3.1

The paper addresses an interesting application of system dynamics to a complex sector and presents a great deal of data in diagrammatic form. This is often very difficult to decipher

Thank you for the encouraging comment.

3.2

I would suggest that the presentation of the Behavioural Tests in  'Results' section in particular are revisited as these are densely presented with insufficient explanation of terminology and it is not clear what they contribute to the discussion and conclusions

We agree that they are densely presented, but the aim of using the behavioural tests is only to validate the model not to contribute to discussion or conclusion. These tests are important and give confidence in the model and results.

3.3

The text also contains some references (eg 'sysdea' line 162 and 'capex' line 181) which are not explained at first use

Thank you for this observation. Now, this has been explained at first use.

The updated text:

“Dependency and check unit consistency was performed using the “dependency tracking” feature in the software used (Sysdea)”. Capex (capital expenditure).

Page 6; line 174,195

3.4

Overall, although interesting as an application the paper currently overwhelms the reader with data which requres a significant amount of specialist expertise to understand.

If the Figure 2 is adopted/reproduced from ref [22], please send the copyright permission you have obtained.

Thank you for this observation. This Figure is taken from our own research paper entitled: “A Systems-Thinking Approach to Address Sustainability Challenges to the Energy Sector”. We confirm that the Figure is designed by our research team.

1.1

First of all, it is an interesting paper which presents an application of system dynamics to analyse the Australian energy sector.

Thank you for the encouraging comment.

1.2

Although authors present the contribution of a system dynamic approach for examining the behavior of the energy sector and why a system dynamic model is an effective management tool, I think that author should provide more details about energy sector in order that reader can understand the challenges and complexity of energy sector. In addition, a more detailed discussion on system dynamics is necessary.

Thank you for this observation and suggestion. We have now provided details about the energy sector challenges. In addition, we have added additional text that describes how the system dynamics is necessary.

Page 1; lines 40-43

Page 2; lines 55-58

1.3

In my view section 3.1 could be a part of section 2.1 because this section presents the CLD and the SFM. Also, section 2.2 could be integrated into section 3.2.

Thank you for your suggestion. If the editor does not mind having long sections we will do that.

1.4

It is not clear how the results from sensitivity analysis lead authors to select the three scenarios. Which was the criterion for the selection of these scenarios?

Thank you for pointing out this. We have amended the manuscript to better explanation how the results from sensitivity analysis can be used to develop three development scenarios for Australian energy sector.

The updated text:

“Three possible scenarios for energy development in Australia were identified. These scenarios were: (1) a no growth scenario, (2) a base case scenario, and (3) a likely to happen scenario as described in Table 1. These scenarios were identified based on the results of a sensitivity analysis. The sensitivity analysis was done by adjusting model parameters by ± 20% to identify the most influential parameters in energy production capacity. The most influential parameter was the gross demand growth rate” parameter.

Page 6; lines 203-208

1.5

Authors have to reconsider the importance of the graphs regarding the behavioral tests and extreme condition tests. Also the discussion on the results from scenarios is poor. It is the main goal of this paper, so I think that authors have to provide more details on each scenario and the behavior of the energy sector system based on the figures 10 and 11.

Behavioural tests are important to show the robustness and reliability of the model, and thus achieve the first aim of the study, which is “to formulate and validate a system dynamics model of the energy sector”, and thus gives more confidence in the obtained results.

Regarding the scenarios, as we cover a complex system (the energy sector) with 7 types of primary energies (black coal, brown coal, gas, wind, solar power, hydro power, and bio power), we thought summarizing scenarios and their results in Table 1 and Table 2, and focusing on the current scenario and implications in the discussion (with considering the other scenarios) would make it easier for the reader. Figures 10 and 11 are for black coal and wind as examples, one for fossil fuel and one for renewables. If we added the rest of the graphs of other energies and discussed in each scenario in detail, the reader would be overwhelmed by graphs and details. So, we sought to make it clearer and easier for the reader as much as possible.

2.1

This is an interesting and well-written article

Thank you for the encouraging comment.

2.2

Some interested readers may not know what GWh stands for. I suggest that a definition is given where the unit first appears (line 88).

Thank you for this observation. A definition of GWh has been provided where the unit first appeared.

The updated text:

“The different forms of energy were put into the same units, Gigawatt-Hour (GWh), one gigawatt is one billion watts. It is a unit that represents the energy used or the energy production capacity, and we used it to express all energy resources. This is used by many sources and it is the scientific way to compare and summarize energies [23]”.

Page 4; lines 120-123

2.3

The authors use both “systems dynamics” and “system dynamics”. They ought to stick with one of them

Thank you for this observation. “Systems dynamics” in line 67 has been corrected to “system dynamics”.

Page 2; line 67

2.4

Reference is made to Laimon et al. [22] in a few places. This is apparently a manuscript that has been submitted for publication, but has not yet been accepted.  Many journals do not permit the inclusion of submitted papers in a list of references.  You should check with this journal about the proper procedure.

Unpublished work has a description in “Applied sciences”. Point 4 (Unpublished work, submitted work, personal communication), to which we adhered.

https://www.mdpi.com/journal/applsci/instructions#references

However, the current paper is a stand-alone article, as it represents the quantitative method and has its own data. In addition, reference [22] is our work.

2.5

The language and grammar are excellent in this paper.  I did notice one error on line 77 (over time in two words instead of one).

Thank you. This has been corrected to “over time”.

Page 2; line 85

2.6

You refer to the curves in Figs. 7-9 as S-shaped growth curves. This does not seem to me to be the proper term to use.  You may simply want to drop the term “S-shaped”.

The term “S-shaped” (line 286) has been dropped as suggested, and the paragraph has been rewritten.

The updated text:

“The extreme condition test results (Figs. 7, 8, and 9) show that the pattern of modelled behaviour did not dramatically change…”

Page 11; lines 297-298

2.7

In Figs. 10(c) and 10(e), the keys or identifications for the different colors given below the graphs do not match the curves in the graphs. For example, Fig. 10(c) identifies 6 different colors below the graph, but only three different colors are used for the curves.  The same applies to Fig. 10(e).

Indeed, they are 6 colours. Blue and red for black coal. Yellow and orange for gas. Green and purple for brown coal. Red and orange hardly appear as they represent the energy production “without bankruptcy”. In other words, “with bankruptcy” and “without bankruptcy” are nearly equal, that implies that capacity bankruptcy has no effect in the case of black coal and gas. “We found the effect of bankruptcy is not considerable in black coal and gas (Fig. 10c, and Fig. 11c)”. (Lines 388-389).

Regarding the brown coal, the green colour cannot be seen, which can be attributed to the drawing scale. Black coal and gas production capacities are in millions, 4 and 1.3 m GWh respectively, while brown coal production capacity is in thousands, only 170k at scenario 1. The same in Fig. 10 (e), coal reserves are huge (more than 500 m GWh), while gas reserves are much less (less than 40 m GWh).

However, these results are clarified in Table 2 (reserves column) and discussion.

2.8

In Table 2, I suggest that you add “year” to the first line in front of 2030, 2050, etc. and above “Scenario 1”.

A “year” has been added to the first line as suggested.

Page 16; line 355

2.9

You ought to define what RE stands for (e.g., line 355).

Now, this is defined where it first appeared.

Page 1; line 43

2.10

You present the prices $93/MWh, $68, and $71/MWh on lines 364-366.  You should identify the source of those data.

The source is the same fig. (Fig 11 b). This has been rewritten to clarify it more.

The updated text:

“If wind and solar are available on demand with a backup power the wholesale price will be around $93/MWh by 2030 (Fig. 11b). Other dispatchable RE resources (hydro power and bio power) will be $68 and $71/MWh respectively”.

Page 17; line 385-386

2.11

Under the list of References, you use et al. in a number of places rather than the complete set of authors.  In the text, it is perfectly proper to use et al. such as Ciscar et al. [13], but in the Reference list you should identify all authors or co-authors.  See also references 15, 16, 18, and 29.

Thank you for this observation, and we totally agree. I used EndNote X8.1 reference management software, and this is done by the software not manually, when we chose “numbered” style. Only reference (1) was done manually to show the co-others. However, I’ll keep all references as shown by EndNote X8 (numbered style), unless the editor has another opinion.

3.1

The paper addresses an interesting application of system dynamics to a complex sector and presents a great deal of data in diagrammatic form. This is often very difficult to decipher

Thank you for the encouraging comment.

3.2

I would suggest that the presentation of the Behavioural Tests in  'Results' section in particular are revisited as these are densely presented with insufficient explanation of terminology and it is not clear what they contribute to the discussion and conclusions

We agree that they are densely presented, but the aim of using the behavioural tests is only to validate the model not to contribute to discussion or conclusion. These tests are important and give confidence in the model and results.

3.3

The text also contains some references (eg 'sysdea' line 162 and 'capex' line 181) which are not explained at first use

Thank you for this observation. Now, this has been explained at first use.

The updated text:

“Dependency and check unit consistency was performed using the “dependency tracking” feature in the software used (Sysdea)”. Capex (capital expenditure).

Page 6; line 174,195

3.4

Overall, although interesting as an application the paper currently overwhelms the reader with data which requres a significant amount of specialist expertise to understand.

If the Figure 2 is adopted/reproduced from ref [22], please send the copyright permission you have obtained.

Thank you for this observation. This Figure is taken from our own research paper entitled: “A Systems-Thinking Approach to Address Sustainability Challenges to the Energy Sector”. We confirm that the Figure is designed by our research team.

1.1

First of all, it is an interesting paper which presents an application of system dynamics to analyse the Australian energy sector.

Thank you for the encouraging comment.

1.2

Although authors present the contribution of a system dynamic approach for examining the behavior of the energy sector and why a system dynamic model is an effective management tool, I think that author should provide more details about energy sector in order that reader can understand the challenges and complexity of energy sector. In addition, a more detailed discussion on system dynamics is necessary.

Thank you for this observation and suggestion. We have now provided details about the energy sector challenges. In addition, we have added additional text that describes how the system dynamics is necessary.

Page 1; lines 40-43

Page 2; lines 55-58

1.3

In my view section 3.1 could be a part of section 2.1 because this section presents the CLD and the SFM. Also, section 2.2 could be integrated into section 3.2.

Thank you for your suggestion. If the editor does not mind having long sections we will do that.

1.4

It is not clear how the results from sensitivity analysis lead authors to select the three scenarios. Which was the criterion for the selection of these scenarios?

Thank you for pointing out this. We have amended the manuscript to better explanation how the results from sensitivity analysis can be used to develop three development scenarios for Australian energy sector.

The updated text:

“Three possible scenarios for energy development in Australia were identified. These scenarios were: (1) a no growth scenario, (2) a base case scenario, and (3) a likely to happen scenario as described in Table 1. These scenarios were identified based on the results of a sensitivity analysis. The sensitivity analysis was done by adjusting model parameters by ± 20% to identify the most influential parameters in energy production capacity. The most influential parameter was the gross demand growth rate” parameter.

Page 6; lines 203-208

1.5

Authors have to reconsider the importance of the graphs regarding the behavioral tests and extreme condition tests. Also the discussion on the results from scenarios is poor. It is the main goal of this paper, so I think that authors have to provide more details on each scenario and the behavior of the energy sector system based on the figures 10 and 11.

Behavioural tests are important to show the robustness and reliability of the model, and thus achieve the first aim of the study, which is “to formulate and validate a system dynamics model of the energy sector”, and thus gives more confidence in the obtained results.

Regarding the scenarios, as we cover a complex system (the energy sector) with 7 types of primary energies (black coal, brown coal, gas, wind, solar power, hydro power, and bio power), we thought summarizing scenarios and their results in Table 1 and Table 2, and focusing on the current scenario and implications in the discussion (with considering the other scenarios) would make it easier for the reader. Figures 10 and 11 are for black coal and wind as examples, one for fossil fuel and one for renewables. If we added the rest of the graphs of other energies and discussed in each scenario in detail, the reader would be overwhelmed by graphs and details. So, we sought to make it clearer and easier for the reader as much as possible.

2.1

This is an interesting and well-written article

Thank you for the encouraging comment.

2.2

Some interested readers may not know what GWh stands for. I suggest that a definition is given where the unit first appears (line 88).

Thank you for this observation. A definition of GWh has been provided where the unit first appeared.

The updated text:

“The different forms of energy were put into the same units, Gigawatt-Hour (GWh), one gigawatt is one billion watts. It is a unit that represents the energy used or the energy production capacity, and we used it to express all energy resources. This is used by many sources and it is the scientific way to compare and summarize energies [23]”.

Page 4; lines 120-123

2.3

The authors use both “systems dynamics” and “system dynamics”. They ought to stick with one of them

Thank you for this observation. “Systems dynamics” in line 67 has been corrected to “system dynamics”.

Page 2; line 67

2.4

Reference is made to Laimon et al. [22] in a few places. This is apparently a manuscript that has been submitted for publication, but has not yet been accepted.  Many journals do not permit the inclusion of submitted papers in a list of references.  You should check with this journal about the proper procedure.

Unpublished work has a description in “Applied sciences”. Point 4 (Unpublished work, submitted work, personal communication), to which we adhered.

https://www.mdpi.com/journal/applsci/instructions#references

However, the current paper is a stand-alone article, as it represents the quantitative method and has its own data. In addition, reference [22] is our work.

2.5

The language and grammar are excellent in this paper.  I did notice one error on line 77 (over time in two words instead of one).

Thank you. This has been corrected to “over time”.

Page 2; line 85

2.6

You refer to the curves in Figs. 7-9 as S-shaped growth curves. This does not seem to me to be the proper term to use.  You may simply want to drop the term “S-shaped”.

The term “S-shaped” (line 286) has been dropped as suggested, and the paragraph has been rewritten.

The updated text:

“The extreme condition test results (Figs. 7, 8, and 9) show that the pattern of modelled behaviour did not dramatically change…”

Page 11; lines 297-298

2.7

In Figs. 10(c) and 10(e), the keys or identifications for the different colors given below the graphs do not match the curves in the graphs. For example, Fig. 10(c) identifies 6 different colors below the graph, but only three different colors are used for the curves.  The same applies to Fig. 10(e).

Indeed, they are 6 colours. Blue and red for black coal. Yellow and orange for gas. Green and purple for brown coal. Red and orange hardly appear as they represent the energy production “without bankruptcy”. In other words, “with bankruptcy” and “without bankruptcy” are nearly equal, that implies that capacity bankruptcy has no effect in the case of black coal and gas. “We found the effect of bankruptcy is not considerable in black coal and gas (Fig. 10c, and Fig. 11c)”. (Lines 388-389).

Regarding the brown coal, the green colour cannot be seen, which can be attributed to the drawing scale. Black coal and gas production capacities are in millions, 4 and 1.3 m GWh respectively, while brown coal production capacity is in thousands, only 170k at scenario 1. The same in Fig. 10 (e), coal reserves are huge (more than 500 m GWh), while gas reserves are much less (less than 40 m GWh).

However, these results are clarified in Table 2 (reserves column) and discussion.

2.8

In Table 2, I suggest that you add “year” to the first line in front of 2030, 2050, etc. and above “Scenario 1”.

A “year” has been added to the first line as suggested.

Page 16; line 355

2.9

You ought to define what RE stands for (e.g., line 355).

Now, this is defined where it first appeared.

Page 1; line 43

2.10

You present the prices $93/MWh, $68, and $71/MWh on lines 364-366.  You should identify the source of those data.

The source is the same fig. (Fig 11 b). This has been rewritten to clarify it more.

The updated text:

“If wind and solar are available on demand with a backup power the wholesale price will be around $93/MWh by 2030 (Fig. 11b). Other dispatchable RE resources (hydro power and bio power) will be $68 and $71/MWh respectively”.

Page 17; line 385-386

2.11

Under the list of References, you use et al. in a number of places rather than the complete set of authors.  In the text, it is perfectly proper to use et al. such as Ciscar et al. [13], but in the Reference list you should identify all authors or co-authors.  See also references 15, 16, 18, and 29.

Thank you for this observation, and we totally agree. I used EndNote X8.1 reference management software, and this is done by the software not manually, when we chose “numbered” style. Only reference (1) was done manually to show the co-others. However, I’ll keep all references as shown by EndNote X8 (numbered style), unless the editor has another opinion.

3.1

The paper addresses an interesting application of system dynamics to a complex sector and presents a great deal of data in diagrammatic form. This is often very difficult to decipher

Thank you for the encouraging comment.

3.2

I would suggest that the presentation of the Behavioural Tests in  'Results' section in particular are revisited as these are densely presented with insufficient explanation of terminology and it is not clear what they contribute to the discussion and conclusions

We agree that they are densely presented, but the aim of using the behavioural tests is only to validate the model not to contribute to discussion or conclusion. These tests are important and give confidence in the model and results.

3.3

The text also contains some references (eg 'sysdea' line 162 and 'capex' line 181) which are not explained at first use

Thank you for this observation. Now, this has been explained at first use.

The updated text:

“Dependency and check unit consistency was performed using the “dependency tracking” feature in the software used (Sysdea)”. Capex (capital expenditure).

Page 6; line 174,195

3.4

Overall, although interesting as an application the paper currently overwhelms the reader with data which requres a significant amount of specialist expertise to understand.

Please carefully read the guidelines outlined in the 'Instructions for Authors' on the journal website

https://www.mdpi.com/journal/applsci/instructions and ensure that your manuscript resubmission adheres to these guidelines. In particular, please ensure that citations within the text are in the correct format; references at the end of the text are in the correct format; figures and/or tables are placed at appropriate positions within the text and are of suitable quality; tables are prepared in MS Word table format, not as images; and permission has been obtained and there are no copyright issues.

The guidelines have been read carefully and the manuscript resubmission adheres to these guidelines. The citations within the text are in the correct format, numbers are placed in square brackets, and no text with pagination is embedded. References at the end of the text are in the correct format using EndNote, and the list includes the full title (ACS style). Figures and tables are placed at appropriate positions within the text and are of suitable quality. Tables are prepared in MS Word table format, not as images; and there are no copyright issues.

3.1

Fig 1 The term RE (Renewable Energy) is defined for (b) but also appears in (a) so needs to be defined earlier

Thank you for this observation. (Renewable Energy) in line 106 has now been cleared, as RE (Renewable Energy) is defined earlier in line 43.

3.2

Lines 114-119 the discussion is hard to follow and the use of  * is not explained

The symbol (*) is a multiplication sign. This symbol and all equations are taken literally from the variable's inspector of the software used (Sysdea). Regarding the discussion, more explanations for Fig. 2 have been made in the first paragraph of research method (lines 82-88) as an introduction to link the current work with Fig. 2 and thus make the discussion easy to follow. 

3.3

120-121 - some grammatical errors?

Thank you for this observation. These lines have been added recently. Now, a few changes have been made.

The updated text:

The different forms of energy were put into the same unit: Gigawatt-Hour (GWh), in which one gigawatt is one billion watts. It is a unit that represents the energy used or the energy production capacity, and we used it to express all energy resources.

Page 4; line 125

3.4

Fig 2 appears without introduction and is not clearly explained - this is important because this Fig is clearly an cricial reference point for the rest of the paper - hence from this point the discussion reamins difficult to follow

Thank you for this observation and suggestion. An introduction has been added as mentioned before (comment 3.2) to explain Fig. 2 to make the discussion easy to follow.

The updated text:

The CLD (Fig. 2) contains twenty one feedback loops including ten reinforcing loops (R1 to R10) and eleven balancing loops (B1 to B11). This CLD highlights the main components of the energy sector linked to Australia's energy policy including energy resources (loops R1 and R2); energy production, supply and demand (loops R3, B3 and B4); energy economics (loops B5 and R4); energy emissions and energy emissions policies (loops R6, B6 and B7); and energy policy developments (loops R7, B8, R8, B9, R9, B10, R10 and B11). Parameters in red colour are missing or poorly performing in the Australian context.

Page 2; lines 82-88

3.5

174 the name 'Sysdea' is not referenced or explained

Thank you for this observation. Now, a reference has been added to easily find all related information about Sysdea.

Page 6; line 177

3.6

214 - where is the systems dynamics model?

Thank you for this observation. The text has been updated to point out the model's location.

The updated text:

The structure of the system dynamics model consists of two linked main models: energy resources extraction pipeline model (Fig. 3 and Fig. 4), and CO₂ emissions model (Fig. 5).

Page 7; line 214