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Energy System Transition in the Context of NDC and Mitigation Strategies in Tunisia

Climate 2022, 10(11), 166; https://doi.org/10.3390/cli10110166

by Panagiotis Fragkos^*

and Eleftheria Zisarou

Reviewer 1: Anonymous

Reviewer 2:

Milad Bagheri

Climate 2022, 10(11), 166; https://doi.org/10.3390/cli10110166

Submission received: 23 September 2022 / Revised: 26 October 2022 / Accepted: 27 October 2022 / Published: 1 November 2022

(This article belongs to the Special Issue Climate Change Mitigation and Adaptation Policies and Strategies in Energy)

Round 1

Reviewer 1 Report

The article presents an interesting topic: modeling the energy system transition in the context of NDC strategies in Tunisia. This article is well elaborated. However, I found some parts that need to improve related to the format and style of the presentation.

Please consider adjusting according to the detailed comments below.

Abstract

The abstract seems clear to me.

Introduction

- The background seems clear in introducing the topic in the study location context. However, since this article is dedicated to international readers, I suggest adding one or more paragraphs (at the very beginning of the introduction section) to discuss the global context of the issue addressed.

- As a scientific article, I recommend adding more elaboration discussing the research gap analysis, before the authors state the research problems and research objectives. Please use recent references (for example last 5 years of research publication) in this part.

- In general, I found insufficient references in the introduction section

Study design

- I suggest adding a map and general information about the study location.

- I suggest adding a figure, describing the schematic flow of the study design.

- Please make sure that all of the data sources used in the model are mentioned.

- Please adjust the format of the table and figure caption to the journal style.

Result and discussion

- Do you use actual or predicted (model) data for the years 2010 and 2020? Please make sure that you have mentioned it in the method section.

- Please adjust the format of the table and figure caption to the journal style.

- Please add a title for X-axis with “Year” for all Figures when applicable.

- Figures 1, 3, and 4: Please correct the position of the Y-axis title.

- Figure 5: Please adjust the Y-axis title to “Share of RES” instead of “%”

- Figure 6: Please add an axis title “Net import dependency”

- Figure 7: Please change the title axis to “Percentage of change from BAU”; please improve the position of the X-axis title

Conclusions

- I suggest making this section more concise by summarizing the main points of your findings. Please also make sure that all the research objectives have been answered.

- I suggest providing a few more sentences/paragraphs on (a) identifying any limitations of this research, and (b) mentioning potential future research routes for other researchers to take up where this research left off.

Reference

Please recheck the reference's style. Make sure that the referencing follows the journal style, and that the references are written consistently and correctly. For example reference 4 (incomplete title?), ref 5 (add access date for online/website source), ref 8 (the use of capital letters), ref 23 (incomplete?), etc.

Author Response

Reviewer 1

Please consider adjusting according to the detailed comments below.

We would like to thank the reviewer for the positive comments on our article. Below, you may find our detailed replies to all your comments and suggestions (in red), which have also been integrated in the revised submission.

Abstract

The abstract seems clear to me.

Thank you for the positive comment. However, we further improved the abstract to reply to the comment of the second reviewer.

Introduction

Thank you a lot for the suggestion. The revised manuscript includes a discussion about the global climate policy landscape in the introduction section. The paragraph below is included:

“Climate change is a great global policy challenges of our time. It is increasingly rec-ognized that unabated climate change can lead to large impacts on the environment and human societies [1]. Limiting climate change has been the subject of international negotia-tions for more than 25 years. In this process, long-term goals have been suggested by the Parties to the UNFCCC, especially under the Paris Agreement aiming to keep global tem-perature rise to well-below 2 °C compared to pre-industrial times and pursue efforts to limit it to 1.5 °C [2]. The Paris Agreement has established a platform to facilitate the moni-toring of countries’ progress towards the long-term mitigation target. Following the Paris Agreement (PA), a large majority of countries representing more than 90-95% of global Greenhouse Gases (GHG) emissions have submitted climate pledges labeled as National-ly Determined Contributions (NDCs). However, countries’ NDCs when aggregated are found to be insufficient to pave the way towards meeting the PA temperature goals [3].”

Thank you for the comment, which helped us improve the quality of our study. The revised version of the manuscript includes additional clarifications and discussion on the research gap, and research objectives of the study, using recent relevant references. The text below is added in the introduction section of the revised manuscript:

“There are some previous efforts to quantify the impacts and requirements for the low-carbon transition in Tunisia, but the research is fragmented and does not cover all sectors of the energy system. For example, all previous decarbonization studies focused on the transformation of Tunisian electricity sector [4,10], neglecting the potential for emissions reduction from energy demand transitions, e.g. in transport and industrial sectors. Other studies focused on specific topics, e.g., on the integration of North Africa and EU electricity systems [11], while others developed only stylized projections for decarbonisation pathways in African countries without considering national energy and climate policies and NDCs and the links of electricity generation with demand sectors [8]. Lastly, so far there is limited research on developing pathways for Tunisia exploring deep decarbonisation goals, while covering all energy-related sources of emissions. These are the main research gaps that we aim to cover with the current study.”

and below:

“This article investigates, discusses, and analyses all options to reduce emissions related to both energy demand and supply -and their complex interlinkages- aiming to provide a holistic assessment of energy transition strategies in Tunisia by 2030 and 2050, which currently lacks in the scientific literature. As the modelling methodology is based on the analysis of integrated energy systems, it provides new, innovative insights on the synergies and trade-offs between demand and supply-side mitigation options in Tunisia, with a focus on the interlinkages between renewable energy expansion, electrification of end-uses and energy efficiency improvements. Our study assesses the interplay between (Conditional and Unconditional) NDC targets for 2030 and the way these can become a roadmap toward long-term low-emission development strategies. The article also explores the link between national decarbonization efforts and the global cost-optimal Paris-compatible pathways, as included in the IPCC Special Report on 1.5^oC [ 13, 14], paving the road for innovative research on synergies between national strategies and the aspirational long-term global Paris goals. The article emphasizes key challenges and opportunities for Tunisia’s energy transition, provides policy recommendations on how to implement its NDC targets for 2030 and even raise its climate ambition towards a low-emission, sustainable and climate resilient development by 2050 compatible with the Paris goals.

- In general, I found insufficient references in the introduction section

The revised version of the manuscript includes additional literature and references.

Study design

- I suggest adding a map and general information about the study location.

Thank you for the suggestion. The revised version of the manuscript include additional details on the study location (Tunisia) and a relevant map

- I suggest adding a figure, describing the schematic flow of the study design.

Thank you for the suggestion. We added a figure describing the schematic flow of the study design in the revised version of the manuscript (figure 2 in section 2.3).

- Please make sure that all of the data sources used in the model are mentioned.

We checked and all data sources used in the model are now mentioned in the manuscript. We added a sentence in section 2 to mention all the data source used in the model. See text below:

“The MENA-EDS uses various sources of data, including IEA database [17] (for energy consumption by sector and detailed energy balances), Enerdata [18] (for energy prices and power generation capacities), EDGAR [19] (for CO2 emissions), World Bank [20] (for economic indicators and transport activity), UN population prospects [21] (for data and projections for population), BGR [22] (for hydrocarbon resources), OICA [23] (for vehicle and car stocks) and the European Commission [24] (for technology costs). The model uses actual data until the year 2020.”

- Please adjust the format of the table and figure caption to the journal style.

We adjusted the format of the table and figure captions to the journal style.

Result and discussion

- Do you use actual or predicted (model) data for the years 2010 and 2020? Please make sure that you have mentioned it in the method section.

Thank you for the comment. We use actual data for the years 2010 and 2020. In the revised manuscript, we added this in the method section.

- Please adjust the format of the table and figure caption to the journal style.

We adjusted the format of the table and figure captions to the journal style

- Please add a title for X-axis with “Year” for all Figures when applicable.

We added a title for X-axis with “year” in all figure captions.

- Figures 1, 3, and 4: Please correct the position of the Y-axis title.

Thank you for the comment. This is corrected

- Figure 5: Please adjust the Y-axis title to “Share of RES” instead of “%”

Thank you for the comment. This is corrected in the revised version of the manuscript.

- Figure 6: Please add an axis title “Net import dependency”

This is corrected in the revised version of the manuscript.

- Figure 7: Please change the title axis to “Percentage of change from BAU”; please improve the position of the X-axis title

Thank you for the comment. This is corrected in the revised version of the manuscript.

Conclusions

- I suggest making this section more concise by summarizing the main points of your findings. Please also make sure that all the research objectives have been answered.

Thank you for the comment, which helped us improve the conclusions section, which has been considerably improved in the revised manuscript. In addition, we added the below text to clarify how the research objectives have been addressed by our study.

“To explore the impacts of policy developments, NDC strategies, and potential Par-is-compatible pathways, we used the MENA-EDS model to simulate a series of scenarios with different climate policy ambition to explore energy sector transformation strategies. It is the first study to analyze mitigation options for Tunisia both in energy supply and demand sectors, including transport, buildings, and industries, also capturing their complex interlinkages, e.g., through electrification of energy end-uses. We also examined ambitious deep decarbonization scenarios for Tunisia reaching about 80% emission reduction from Baseline levels in 2050 requiring fundamental transformations of the energy, industrial and transport systems of Tunisia. The analysis shows that Tunisia can explore its large renewable energy potential to decarbonize its economy, diversify the energy mix, eliminate inefficient energy subsidies, and plan towards a cost-effective transformation, ensuring compatibility with Paris goals.”

Very nice suggestion. The revised version of the manuscript includes one paragraph identifying the main limitations of our research and including potential future research pathways. This paragraph is added in the conclusions section and can be found below:

“The study can be expanded in various dimensions that were not fully captured in this paper and could be the basis of future research. The current study does not analyse the broad socio-economic and industrial impacts of NDCs and low-emission strategies for Tunisia. This aspect should be covered in future works as well as the analysis of possible policy measures to boost the economy and create jobs. The deep decarbonization of sectors with hard-to-abate emissions (e.g. heavy industry, aviation) should also be explored. The model-based projections crucially depend on the assumptions made, especially on the values of specific elasticities, including the income and price elasticities determining the evolution of energy consumption by sector. A comprehensive sensitivity analysis on the values of these elasticities or on technology costs is required to consistently evaluate the impacts of NDCs and other climate policies. Finally, the addition of other modelling tools towards a multi-model scenario comparison study, as done in [47], can help us derive more robust policy recommendations.”

Reference

Thank you for the comment. We rechecked and corrected the reference style in the revised version of the manuscript. We also added new references and literature as required by the reviewers.

Reviewer 2 Report

Broad comments

Due to its overall poor language and technical quality, this article needs considerable and severe restoration and improvement. There are several phrases that need to be changed since they don't fit the study report. the research procedures and findings are not sufficiently well-accurate to be published even after a significant and fundamental alteration.

Abstract

· The findings and contributions of the paper are not well expressed in the abstract. In addition, specifics on the study methodology and key findings or outputs are required. Consequently, the abstract must be significantly improved, particularly the actual results.

Keywords

Please update and clarify the key phrases. Please use the words that have been underlined in the article as your search terms.

Use different words entirely for the title and keyword.

Introduction and literature

· There are a few repetitions in the opening portion. Make adjustments as necessary.

· The literature review is primarily responsible for how one study differs from others in the same field of inquiry.

· The literature and introduction are both rather condensed. So what makes this research important?

· By using the research report style, the authors should enhance the introductory and literature review sections. This passage cannot be published in the Land Journal.

· If more study is done on the approaches and tools used to examine integrated systems, the effort will be considerably more effective.

Methodology

Where does the collection of data fit in?
Which types of data have you used?
Where is the result section?
Where is the discussion section?
Please include all of the information listed above in the text's main body.
I believe that additional specifics and references should be used to characterise the study area.

Result

· Please separate the result and discussion in accordance with the guidelines for the journal.

· The results section is brief and ineffective. Please revise and update it.

Discussion

· Please check it and put it in a suitable place on the paper.

Conclusion

The conclusion might be improved and modified to emphasise the study's results more than any issues or implications. What makes research novel? What "limitations of research" are there? Please place the section titled "Recommendations and Future Work" in conclusion.

Specific comments

All figures should be enlarged so that all details can be seen.

v There are also a few grammatical/punctuation errors throughout the text that need to be corrected.

v To meet publishing requirements, such as making sure the research is done in a sound way, the current form needs to be changed a lot.

v You need to better distribute the knowledge portions between the materials and methods, results, and discussion.

v Before the paper is accepted, all these critical issues must be explained reasonably in the Materials and Methods section.

Author Response

Reviewer 2

Broad comments

Thank you for the comment, which helped us to considerably improve our manuscript. We hope that the revised version of the manuscript meets your expectations and can be accepted for publication in the Climate journal. Below, you may find our detailed replies to all your comments and suggestions (in red), which have also been integrated in the revised submission.

Abstract

The findings and contributions of the paper are not well expressed in the abstract. In addition, specifics on the study methodology and key findings or outputs are required. Consequently, the abstract must be significantly improved, particularly the actual results.

Thank you for the comment. We improved the abstract substantially in the revised manuscript, especially to add more details on the results and key findings of the study. The revised abstract can be found below:

“The evolution of the Tunisian energy system in the next decades will highly depend on the implementation of its Nationally Determined Contribution until 2030 and the potential long-term low-emission strategies. The study analyses the technology, emission, energy system and economic impacts of meeting Tunisia’s NDC targets (conditional and unconditional) and long-term transition pathways compatible with the Paris Agreement. Different climate policy targets and settings are explored using the detailed energy system model (MENA-EDS) that integrates detailed representations of energy demand and supply and their complex linkages through energy pricing. The analysis shows that to meet its NDC targets for 2030, current climate policies in Tunisia need substantial strengthening, based on the massive uptake of renewable energy technologies (especially solar PV and wind) and the reduction of oil and gas use. The long-term low-emission transitions leading to emissions reduction of about 80% from Baseline levels in 2050 is based on further expansion of renewable energy within and beyond the electricity sector, increased electrification of energy end-uses (especially through the uptake of electric vehicles in transport), accelerated energy efficiency improvements in transport, industries and buildings, and emergence of low-carbon fuels. The study provides insights on the challenges to achieve deep decarbonization of Tunisian economy, but also on the opportunities from energy sector restructuring, including reduced energy import dependence and increased low-carbon investment.”

Keywords

Please update and clarify the key phrases. Please use the words that have been underlined in the article as your search terms.

Keywords are changed in the revised manuscript.

Use different words entirely for the title and keyword.

Thank you for the suggestion, which we accommodated in the revised manuscript by changing our keywords.

Introduction and literature

There are a few repetitions in the opening portion. Make adjustments as necessary.

Thank you for the comment. We avoid repetitions in the revised version of the manuscript.

The literature review is primarily responsible for how one study differs from others in the same field of inquiry.

Thank you for the comment, which helped us improve the introduction section. In the revised version of the manuscript, we added a paragraph describing how our study differs from others in the same field. The added text can be found below:

This paper provides a quantitative model-based analysis of energy system restructuring and clean technology uptake in case Tunisia meets its NDC targets for 2030 and then engages into a low-emission transition by 2050. Using a comprehensive energy system model (MENA-EDS) [12], the study covers in detail the interactions between energy demand and supply and estimates the required investment in low-carbon technologies in order to meet the Tunisian emission reduction targets. The study shows that the NDC implementation largely relies on the transformation of the electricity sector with rapid up-scaling of renewable technologies combined with the reduction of fossil-based power generation by 2030. Implementing the Tunisian NDCs can set the way towards structural transformations required to ensure a low-emission development strategy compatible with the Paris Agreement goals [7]. Tunisia’s has large renewable energy resources that can be exploited to replace fossil fuel use in and beyond the power sector. Enhanced climate policy ambition can increase renewable energy expansion, accelerate energy efficiency improvements, and electrification of end-uses. As Tunisia’s economy relies heavily on hydrocarbon imports, numerous opportunities exist in reducing its energy import bill through developing domestic renewable energy and reducing fossil fuel imports [8]. “

The literature and introduction are both rather condensed. So what makes this research important?
By using the research report style, the authors should enhance the introductory and literature review sections. This passage cannot be published in the Land Journal.

Thank you for the comments. As a reply, we substantially expanded the introductory and literature review sections in the revised version of the manuscript. You may find below the changes we implemented in the revision: However, please note that the paper was submitted in the Climate journal and not in the Land journal, as pointed out by the reviewer.

In the introduction section, we added a discussion about the global climate policy. The paragraph below is included:

We also added additional details and references in the literature review, enhancing the section and explaining why our research study is important. The text below has been inserted:

There are some previous efforts to quantify the impacts and requirements for the low-carbon transition in Tunisia, but the research is fragmented and does not cover all sectors of the energy system. For example, all previous decarbonization studies focused on the transformation of Tunisian electricity sector [4,10], neglecting the potential for emissions reduction from energy demand transitions, e.g. in transport and industrial sectors. Other studies focused on specific topics, e.g., on the integration of North Africa and EU electricity systems [11], while others developed only stylized projections for decarbonisation pathways in African countries without considering national energy and climate policies and NDCs and the links of electricity generation with demand sectors [8]. Lastly, so far there is limited research on developing pathways for Tunisia exploring deep decarbonisation goals, while covering all energy-related sources of emissions. These are the main research gaps that we aim to cover with the current study.

This article investigates, discusses, and analyses all options to reduce emissions related to both energy demand and supply -and their complex interlinkages- aiming to provide a holistic assessment of energy transition strategies in Tunisia by 2030 and 2050, which currently lacks in the scientific literature. As the modelling methodology is based on the analysis of integrated energy systems, it provides new, innovative insights on the synergies and trade-offs between demand and supply-side mitigation options in Tunisia, with a focus on the interlinkages between renewable energy expansion, electrification of end-uses and energy efficiency improvements. Our study assesses the interplay between (Conditional and Unconditional) NDC targets for 2030 and the way these can become a roadmap toward long-term low-emission development strategies. The article also explores the link between national decarbonization efforts and the global cost-optimal Paris-compatible pathways, as included in the IPCC Special Report on 1.5^oC [ 13, 14], paving the road for innovative research on synergies between national strategies and the aspirational long-term global Paris goals. The article emphasizes key challenges and opportunities for Tunisia’s energy transition, provides policy recommendations on how to implement its NDC targets for 2030 and even raise its climate ambition towards a low-emission, sustainable and climate resilient development by 2050 compatible with the Paris goals.”

If more study is done on the approaches and tools used to examine integrated systems, the effort will be considerably more effective.

Thank you for the comment. Indeed, one of the key innovations of the current study is that (contrary to other similar studies) we use an integrated energy demand and supply system model- MENA EDS. Details on the integrated modelling methodology are presented in section 2. However, to show the importance of the integrated approach we added this sentence in the introduction section, as below:

“As the modelling methodology is based on the analysis of integrated energy systems, it provides new, innovative insights on the synergies and trade-offs between demand and supply-side mitigation options in Tunisia, with a focus on the interlinkages between renewable energy expansion, electrification of end-uses and energy efficiency improvements”

Methodology

Where does the collection of data fit in?
Which types of data have you used?

In the revised version of the manuscript, we added a dedicated paragraph in the methodology section on the data used (and relevant data sources) for the development of the modelling tool. Please see below:

Where is the result section?

The results of our study are included in Section 3 “Model-based Results”.

Where is the discussion section?

Thank you for the comment. Based on your suggestion, we decided to add a “Discussions” section (section 4 of the revised manuscript)

Please include all of the information listed above in the text's main body.

The revised version of the manuscript includes all the above information in the main text.

I believe that additional specifics and references should be used to characterise the study area.

Thank you for the comment. Based on your suggestions, we decided to include additional clarifications, reference, and explanations in the methodology section. The text below has been added:

“MENA-EDS is a recursive dynamic energy system simulation model. Endogenous model variables (e.g. energy consumption) are calculated based on the evolution of explanatory variables (e.g. economic activity, energy prices) through econometrically estimated elasticities, other parameters (e.g. Heating or Cooling Degree Days) and policy-related variables (e.g. carbon price). The economic decisions regarding the investment and operation of the energy system and related technologies are based on the myopic anticipation of future technology costs and system or climate constraints. The model uses myopic anticipation, while some foresight can be forced in the electricity production sector. The core operating principle of MENA-EDS model is that of market equilibrium [12]. The representative agents included in the modelling framework (e.g., energy consumers, power suppliers) use information on energy commodity prices and decide on the allocation of resources [12]. These representative agents interact with each other through the energy markets, simulated in MENA-EDS [25]. The model solves for a set of market prices so that supplies and demands are balanced in all energy markets [26]; in other words, market equilibrium is assumed to take place in each one of the energy markets (partial equilibrium). The demand and supply modules interact with each other in the solution process iterating on market prices until the demand-supply equilibrium is reached.”

In addition, we added a figure describing the schematic flow of the study design in the revised version of the manuscript (figure 2 in section 2.3).

Result

Please separate the result and discussion in accordance with the guidelines for the journal.

Thank you for the comment. In the revised version of the manuscript, the discussion section is separated from the results in accordance with the journal guidelines.

The results section is brief and ineffective. Please revise and update it.

The revised version of the manuscript includes additional details in the results section.

Discussion

Please check it and put it in a suitable place on the paper.

Thank you for the suggestion. A detailed discussion about the results of the study is now included in Section 4 of the revised manuscript.

Conclusion

Thank you a lot for the comment, which helped us improve our manuscript. The section title is changed based on your suggestion. In the revised version of the manuscript, we also added a paragraph on the limitations of the research and future work directions. You can also find it below:

Specific comments

All figures should be enlarged so that all details can be seen.

In the revised manuscript, all figures have been enlarged and improved, also based on the comments of the first reviewer.

v There are also a few grammatical/punctuation errors throughout the text that need to be corrected.

A native English speaker proofread the revised manuscript and the grammatical/punctuation errors have been corrected.

v To meet publishing requirements, such as making sure the research is done in a sound way, the current form needs to be changed a lot.

Based on the comments we received from two reviewers, we have made extensive additions and changes in the revised manuscript. We sincerely hope that the new version meets your expectations.

v You need to better distribute the knowledge portions between the materials and methods, results, and discussion.

Thank you for the comment. Indeed, we made structural changes in the revised manuscript, including an addition of the discussion section (Section 4) and improved the distribution of knowledge portions between sections 2 (materials and methods), section 3 (results) and section 4 (discussion).

v Before the paper is accepted, all these critical issues must be explained reasonably in the Materials and Methods section.

Thank you a lot for the detailed comments. The revised manuscript includes detailed explanations and clarifications for all critical issues raised. We sincerely hope that the revised paper meets your expectations and can be accepted for publication in the Climate journal.

Round 2

Reviewer 1 Report

Dear Authors,

Thank you for the revised version of your manuscript. In general, I found this manuscript has been significantly adjusted incorporating the Reviewers' comments.

However please find my last comments below:

- Line 154-163: I just wonder about some of the blue-colored and underlined words. Please check whether the style is necessary.

- Thank you for providing Figure 2. In my opinion, you do not need to mention the source here if the figure was originally from the Authors.

- Please put all of the figure captions below the figures.

- To me, the presentation of some tables and figures still needs improvement, but it depends on the Editor's decision.

Congratulation.

Author Response

Thank you for the revised version of your manuscript. In general, I found this manuscript has been significantly adjusted incorporating the Reviewers' comments.

However please find my last comments below:

- Line 154-163: I just wonder about some of the blue-colored and underlined words. Please check whether the style is necessary

Thank you for your comment. We further improved the style between Line 154-163, removing blue-coloured and underlined words.

- Thank you for providing Figure 2. In my opinion, you do not need to mention the source here if the figure was originally from the Authors.

Thank you for your comment. We removed the ‘’source’’ from Figure 2.

- Please put all the figure captions below the figures.

Thank you for your comment. We adjusted the figure captions from the entire article.

- To me, the presentation of some tables and figures still needs improvement, but it depends on the Editor's decision

Thank you for your comment. We tried to optimize the diagrams to the extent we thought fit best.

We would like to thank again the reviewer for the positive comments on our article

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Energy System Transition in the Context of NDC and Mitigation Strategies in Tunisia

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