Cross-Validation of the MEDEAS Energy-Economy-Environment Model with the Integrated MARKAL-EFOM System (TIMES) and the Long-Range Energy Alternatives Planning System (LEAP)

Round 1

Reviewer 1 Report

1. The authors tend to exaggerate when explaining their model.  eg line 59:

The novel approach used in MEDEAS proposes unprecedented modelling framework ....

The framework could be better explained by a diagram highlighting all the components considered.

2. The authors underrate the other models.  eg line 119:

it just represent a reference estimation for the end goal of a decarbonizing transition scenario  ....

More details of all models could be provided, but probably better as diagrams.

This could be better phrased.

3. line 176 states that:

The dimensions adjustment on outputs units has been taken into account.

This should be detailed - could be in another appendix.

4. terminology used inside and at the end of the paper should be consistent.  eg Annex 1 and Annex 2 are used in the paper to refer to Appendix A and Appendix B at the end.

5. For Table 3, it would help to label each line of the table, since they are referred to in the text – 5, 6, 7 fossil extraction ….11, 23 … so we can easily identify the variables in question.

6. Figure 2 is faint and it is difficult to read the variables along the x-axis. – but these do have the numbers which could be used to refer back to Table 3 if the lines were numbered.  Similarly with Figure 3 and Table 6, with Figure 4 and Table 9 and with Figure 5 and Table 10.

Also with Figures 4 and 5, it's almost worth stopping the graph lower, say at 20  and putting the actual value (35) in brackets at the top, so the detail can be clearer.

In line 386 disequilibrium needs defining….  anything which alters the comparisons should be explained clearly.

Some English expression needs to be tidied up - too many 's's.

176 The dimensions adjustment on outputs units has been taken into account.

should be: the dimension adjustment on output units has ...

264 ... the increase in renewables implementation’s rates

should be: the increase in renewable implementation rates...

279  ... Decreasing in RMSDs with time is observed, in variables 

should be:  Decreases in RMSD over time can be observed ....

Author Response

Dear Reviewer

Thanks a lot for your comments and suggestions.  Following you will find the reply to all your observations, we are grateful for your precious suggestions and to help us in improving our manuscript.

Best Regards

Author Response File: Author Response.docx

Reviewer 2 Report

In this article, the authors compared the response of MEDEAS models with TIMES and LEAP in depicting the energy transition in two different countries, Austria and Bulgaria. The preliminary results show a good agreement across all the models in representing scenarios projecting historical trends, while a major discrepancy is detectable when the rate of implementation of renewable energy is forced to increase to achieve energy system decarbonization.

I can recommend this article for being published once a few suggestions are considered:

1. In the first paragraph of the introduction, the authors argue: “A model is a mathematical representation of the phenomenon under study. Models are meant to capture patterns or regularities in empirical data by altering parameters that correspond to variables that are thought to affect the phenomenon [1], [2], [3], [4], [5], [6]. Model specification is difficult because our knowledge about the phenomenon being modelled is rarely complete. This theme becomes even more difficult when the phenomena under study concern the dynamics of complex systems like socio-economic systems, energy systems and environmental systems that are all interconnected by a dense network of feedbacks. In this case, it is necessary to resort to the use of complex scientific models, the Integrated Assessment Models (IAMs), created to simulate coupled human and environmental systems by linking dynamics related to society and economy with dynamics in the biosphere and atmosphere into one modelling framework [7], [8]. However, there has been a call for complexity science to underpin the development of new models[9].” Personally, I think this paragraph is too abstract and full of obviousness. In addition, it is observed how certain general and abstract statements are referenced in a massive way.
2. In the introduction I am missing a contextualization of the real problem. That is my suggestion. There are several relevant studies on and globalization and the shifting centers of gravity of world's human dynamics where the global effect of decoupling between urbanization dynamics and CO2 impact can be observed.
3. In this work, topics related to the physics of complex systems are commented in several parts as for example in the discussion “Today, several IAMs coexist to deal with the complex interactions, high uncertainties and knowledge gaps between interconnections within the environment and human societies" Personally, I think that the authors should include reference to relevant studies on these dynamics and relevant authors such as Barabasi, Morales or Bar-Yan. In the case of hyper-connected systems, it is also interesting to review articles on deglobalization that anticipate the collapse of systems with an excessive number of interconnections.
4. Finally, I think that the authors should include a point of conclusions to summarize the most important results obtained.

Author Response

Dear Reviewer

Thanks a lot for your comments and suggestions.  Attacched you will find the reply to all your observations, we are grateful for your precious suggestions and to help us in improving our manuscript.

Best Regards

Author Response File: Author Response.docx