A Spatially Highly Resolved Ground Mounted and Rooftop Potential Analysis for Photovoltaics in Austria

Round 1

Reviewer 1 Report

The authors showcase the potential of ground-mounted and rooftop solar in Austria. The paper suffers from layout issues when results come prior to methodology making it difficult to interpret the results. There are also problems with language and grammar affecting the cohesiveness of the paper. The literature review is appropriate, but it could be improved. The authors should consider resubmitting after rewriting it in the standard format with a strong discussion of results.

Author Response

The paper has been restructured (1. Introduction, 2. Materials & Methods, 3. Results, 4. Discussion, and 5. Conclusions) and a comprehensive language and grammar check was performed. Additionally, the different sections has been substantially improved and extended.

Reviewer 2 Report

In my opion the papper is well organised and deserves to be published in the present form

Author Response

Thank you very much for your comment. Despite, we have further extended
the manuscript will gladly accept comments on the new version.

Reviewer 3 Report

This manuscript presents a general method for the assessment and evaluation of solar energy along with landuse in Austria. Both ground-mounted installations and rooftop modules were taken into consideration. The manuscript is in-general well-written. However, I do have some significant concerns.

To me, the satellite image at 10m spatial resolution can not be treated as high spatial resolution source. If consider the rooftop modules, the raster data at meter level should be considered as high resolution. The authors should compare the method to airborne-based or drone-based mapping data with much higher resolution than the satellite imagery, or discuss this theoretically. Below are some discussions on this topic.

Koc, A. B., Anderson, P. T., Chastain, J. P., & Post, C. (2020). Estimating Rooftop Areas of Poultry Houses Using UAV and Satellite Images. Drones, 4(4), 76.

Yang, B., Hawthorne, T., Torres, H., Feinman M. (2019). Using Object-Oriented Classification for Coastal Management in the East Central Coast of Florida: A Quantitative Comparison between UAV, Satellite, and Aerial Data. Drones, 3(3), 60.

Other comments:

Map figures lack some elements, e.g. north arrow, indicator shows where is study region located.

I see both SENTINEL-II and Sentinel-2 were used in the manuscript. Please keep consistent if this refers to the same source. Also, please specify which system (A or B or others).

Author Response

This manuscript presents a general method for the assessment and evaluation of solar energy along
with landuse in Austria. Both ground-mounted installations and rooftop modules were taken into
consideration. The manuscript is in-general well-written. However, I do have some significant
concerns.
To me, the satellite image at 10m spatial resolution can not be treated as high spatial resolution
source. If consider the rooftop modules, the raster data at meter level should be considered as high
resolution. The authors should compare the method to airborne-based or drone-based mapping
data with much higher resolution than the satellite imagery, or discuss this theoretically. Below are
some discussions on this topic.
Koc, A. B., Anderson, P. T., Chastain, J. P., & Post, C. (2020). Estimating Rooftop Areas of Poultry
Houses Using UAV and Satellite Images. Drones, 4(4), 76.
1
Yang, B., Hawthorne, T., Torres, H., Feinman M. (2019). Using Object-Oriented Classification for
Coastal Management in the East Central Coast of Florida: A Quantitative Comparison between UAV,
Satellite, and Aerial Data. Drones, 3(3), 60.
ad rooftop PV: we used official vector data from governmental sources. In
order to present this information more coherent we have rephrased the
Input Data section:
For the assessment of building footprints and the available rooftop area we
processed official cadastral vector data extracted from \url{basemap.at} for
rooftop PV.
ad ground mounted PV: As correctly stated we used a 10m spatial resolution
data set for the whole country (approximately 84 thousand square
kilometres) which we considered as high resolution when analyzing landuse
values.
Other comments:
Map figures lack some elements, e.g. north arrow, indicator shows where is study region located.
We have updated the figures accordingly, The first map (Figure 4) shows a
small overview map, all maps show north arrows.
I see both SENTINEL-II and Sentinel-2 were used in the manuscript. Please keep consistent if this
refers to the same source. Also, please specify which system (A or B or others).
We have addressed this issue, and used the correct term: Sentinel-2
everywhere in the script. The satellite data itself was processed by others
(Umweltbundesamt / Austrian Environment Agency) and therefore not part
of our investigation. Details on the twin satellites (A / B) are beyond our
knowledge.

Reviewer 4 Report

I would like to thank the authors for the manuscript, which gave quite a bit of thoughts on PV implementation in order to achieve the goals set. The analysis of how to achieve Europe’s neutrality by 2050 is of interest and necessary for the scientific community, decision-makers, and the public in general.

The impression after the reading is that the manuscript is not organically complete.

First of all, several technical comments:

It is unexpected that Conclusions (Section 4) comes before the Discussion part (Section 5). If it is so, then Conclusions are not a concluding part of the manuscript.

“Results (Section 2) comes before the Discussions (Section 5).

It is unclear the purpose of Appendix 1: what value-added information it provides to the readers giving land use codes?

In Section 3 “Materials and Methods” analysis assumptions, selected tools for analysis. However, the results of the analysis somehow are not presented. In Section 5 “Discussions” elaboration could be done without analysis (taking only the assumptions).

In Table 4 five scenarios are presented. However, in section 5 “Discussions” only two of them are elaborated.  On the other hand – those scenarios are presented already in Section 2 “Results”.

In the Discussions section, there is no evidence-based analysis.

In general, the authors should rethink the philosophy of the manuscript and what they would like to present to the scientific community. Currently seems it is more descriptive than an analysis-based manuscript.

Author Response

I would like to thank the authors for the manuscript, which gave quite a bit of thoughts on PV implementation in order to achieve the goals set. The analysis of how to achieve Europe’s neutrality by 2050 is of interest and necessary for the scientific community, decision makers, and the public in
general.
The impression after the reading is that the manuscript is not organically complete.
First of all, several technical comments:
It is unexpected that Conclusions (Section 4) comes before the Discussion part (Section 5). If it is so, then Conclusions are not a concluding part of the manuscript.
“Results (Section 2) comes before the Discussions (Section 5).
The paper is now completely restructured (1. Introduction, 2. Materials &
Methods, 3. Results, 4. Discussion, and 5. Conclusions). We apologize for
using a deprecated template.
It is unclear the purpose of Appendix 1: what value-added information it provides to the readers
giving land use codes?
We provide this table in the appendix to clearly show which scenario uses
which types of land-use. If neccessary the table can be removed and put
next to the openly available data on zenodo.
In Section 3 “Materials and Methods” analysis assumptions, selected tools for analysis. However,
the results of the analysis somehow are not presented. In Section 5 “Discussions” elaboration could
be done without analysis (taking only the assumptions).
In Table 4 five scenarios are presented. However, in section 5 “Discussions” only two of them are
elaborated. On the other hand – those scenarios are presented already in Section 2 “Results”.
In the Discussions section, there is no evidence-based analysis.
We have restructured the paper following your comments. Section
"Materials and Methods" presents the software and data, including the
parameters chosen to run the model. Accordingly, we do not present any
results in this section. The discussion section has been adapted and
extended.
In general, the authors should rethink the philosophy of the manuscript and what they would like
to present to the scientific community. Currently seems it is more descriptive than an analysisbased
manuscript.
Based on our analysis we have tried to make our argumentation more
coherent. Therefore, we rephrased parts of the discussion and conclusion
sections. Our main result is that theoretically the goal of meeting 11 TWh in
2030 can be achieved solely with the rooftop PV potential. However,
considering the necessary installation efforts, the associated costs of small
and dispersed production units and finally the inherent uncertainty with
respect to the willingness of tens of thousands of individual home owners to
install PV systems, installing the necessary solar PV on buildings alone is
constrained.

Round 2

Reviewer 1 Report

The authors have sufficiently revised the manuscript. The only minor comment would be to include the colour bar for Fig 6.

Author Response

Thank you very much for your suggestion to include a legend for Figure 6, we have changed the figure accordingly.

Reviewer 3 Report

I have no more comments

Author Response

Thank you very much for the review. We have further improved grammer and spelling and fixed typos throughout the whole document.

Reviewer 4 Report

Dear Authors,

Thank you for the updated manuscript. 

It is definitely updated and the majority of previous comments were taken into account.

In my understanding some points could be improved:

In Line 24 the dimensions should be TWh or TWh/a?

Line 25: is truly 1.7 TWh/a is indicated in Reference 3?

Equation 1: the correct punctuation would be appreciated (dot).

In the text, there is "table", why in legends "Table". The same with Figures.

Table 3: I would recommend for the sake of clarity include "spelling" of coefficients (even though they have been explained in the text above the table).

If in Line 25 "today’s production" is correct then in Line 151 the total production in 2030 should be 23.5 TWh/a

Figure 7 - for Austrians probably the borders and locations of municipalities are clear. For others - it is just a map of Austria. 

Line 195: 4-4.4 TWh/a, while Figure 8: 4-4.5 TWh/a.

Lines 199-200: "a maximum yearly installed additional capacity of 250MWp ([47]), we extrapolate a production of additional 4.5TWh/a by 2030". Are numbers are OK here?

Line 288: "installations should concentrate on buildings with a footprint of more than 250m2 to 500m2" - on what grounds this statement is in the conclusions? The 3rd conclusion is not supported by the text. 

Appendix 1 Table - it is still unclear what is the benefit of this Table for the manuscript. What land-use codes can provide in this case?

Author Response

Dear Reviewer,

Thank you very much for the thorough review.

In Line 24 the dimensions should be TWh or TWh/a?

We have corrected it to TWh/a

Line 25: is truly 1.7 TWh/a is indicated in Reference 3?

We have improved the sentence, including an update to the reference. 1.7TWh/a is correct (as of 2019, preliminary figures for 2020 exist with about 2TWh/a)

Equation 1: the correct punctuation would be appreciated (dot).

corrected

In the text, there is "table", why in legends "Table". The same with Figures.

corrected

Table 3: I would recommend for the sake of clarity include "spelling" of coefficients (even though they have been explained in the text above the table).

we have included a column with a short description

f in Line 25 "today’s production" is correct then in Line 151 the total production in 2030 should be 23.5 TWh/a

We fixed this typo (23.4 is correct, the typo was in 21.8 -> 21.7)

Figure 7 - for Austrians probably the borders and locations of municipalities are clear. For others - it is just a map of Austria. 

We updated the figure and highlighted several regions with a short description in the text

Line 195: 4-4.4 TWh/a, while Figure 8: 4-4.5 TWh/a.

We have corrected this mistake

Lines 199-200: "a maximum yearly installed additional capacity of 250MWp ([47]), we extrapolate a production of additional 4.5TWh/a by 2030". Are numbers are OK here?

According to Biermayr 2020 only 2013 slightly more than 250 MWp were installed, the following years between 150 - 190 MWp were installed with an increase in 2019 to 247MWp. Numbers for 2020 show that 450MWp were funded, but only part of it was installed during 2020. Our extrapolation therefore quite conservative, but a "safe bet".

Line 288: "installations should concentrate on buildings with a footprint of more than 250m2 to 500m2" - on what grounds this statement is in the conclusions? The 3rd conclusion is not supported by the text. 

We have updated the paragraph to the following:

Round 3

Reviewer 4 Report

Dear Authors,

Thank you for the updated manuscript.

Seems all the comments were taken into account.

I wish you every success in your research.