Integrating Solar Energy into German Vineyards: A Geospatial Framework for Identifying Agrivoltaic Potential

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The abstract is not suitable for a scientific article. It does not report any results, making it impossible to assess the actual contribution of the work. It lacks a summary of methods, results, and implications, elements that are essential for a research article.

Lines 26–32: The introduction frames the context in terms of energy transition and land-use conflicts, but it lacks a clear research gap. The text effectively reiterates well-known policy objectives without providing a specific scientific or methodological contribution.

Lines 33–38: The discussion on public acceptance and dual-use land systems is vague and descriptive. No references to empirical data or conceptual frameworks are provided. The statements are speculative and lack analytical depth.

Lines 39–44: The technical description of agrivoltaic systems remains superficial. No mention is made of the heterogeneity of agrivoltaic designs or performance trade-offs. This oversimplification weakens the scientific rigor of the argument.

Lines 45–48: Germany is presented as an “ideal context” for agrivoltaics, but no quantitative evidence (on land availability or regulatory support) is provided to substantiate this claim. The reference to national land use is insufficient as a scientific justification.

Lines 49–58: The discussion on viticulture and climate change is a general summary of existing literature. However, the authors do not define how their study goes beyond previous work or addresses unresolved questions. The text does not clarify what “long-term trials” would entail or how the current manuscript relates to those trials.

Lines 59–65: Key constraints such as slope gradient and varietal sensitivity are mentioned, but the manuscript does not specify whether or how these factors are operationalized in the analysis. This raises concerns about methodological transparency and replicability.

Lines 66–70: The claim about “growing methodological convergence” is unsubstantiated. No comparison or synthesis of previous spatial modeling approaches is provided. The manuscript lacks a critical review of existing spatial assessment tools or models.

Lines 71–75: The objectives of the study are loosely stated. The phrase “to systematically identify vineyard plots” remains generic and does not define specific research questions or hypotheses. Furthermore, the proposed GIS-based framework is mentioned without any indication of novelty, validation, or reproducibility.

Lines 79–86: The study area is extensively described, but the information is mostly descriptive and not directly tied to the research design. The relevance of the regional context to the methodological framework remains vague.

Lines 87–102: The discussion on vineyard heterogeneity is not modeled. This is a critical omission, as slope, trellis systems, and planting density directly affect agrivoltaic feasibility. Their exclusion undermines the robustness of the spatial analysis.

Lines 114–119:The claim that Rhineland-Palatinate is a “representative model region” is unsubstantiated. No benchmarking against other viticultural regions is provided. Additionally, the parameters listed are not innovative and reflect standard GIS inputs.

Lines 121–127:The methodological framework lacks novelty. The use of QGIS and public datasets is common in land suitability studies and does not represent a scientific advancement. No validation procedure or reproducibility protocol is described.

Lines 128–139:The grid data processing is not rigorous. The use of a “community-curated” electricity map raises concerns about data reliability. There is no mention of data quality control or validation against official sources.

Lines 140–154: The proximity analysis based on centroid-to-point distance is overly simplistic and fails to consider real-world constraints such as elevation differences, parcel geometry, or actual grid access capacity. No sensitivity analysis is performed.

Lines 155–158: The agronomic and physical selection criteria are not derived from experimental data or validated thresholds. Their inclusion appears arbitrary, and the absence of expert consultation or stakeholder engagement weakens their legitimacy.

Lines 171–180: Slope classes are not justified based on field data or agrivoltaic design standards. The classification appears borrowed from vineyard management literature without adaptation to the structural requirements of PV installations.

Lines 187–194: The exclusion of Natura 2000 sites is justified, but there is no spatial analysis of how much potentially suitable area is lost due to this filter. Moreover, legal references are cited but not operationalized.

Lines 195–203: The vine age parameter is weakly connected to actual agrivoltaic implementation potential. No evidence is provided that older vineyards are more suitable for retrofitting, and the five age classes appear arbitrary

Lines 211-219: No statistical metrics or accuracy indicators are used to evaluate model performance. The methodological framework lacks any form of empirical testing.

Lines 221–226: The distinction between total vineyard area and “planted area” is not supported by a transparent filtering methodology. There is no description of how non-cultivated areas were excluded or validated.

Lines 235–237: The area-based statistics are presented without uncertainty ranges or sensitivity analysis. The analysis assumes uniform feasibility within each distance buffer, which is unrealistic given terrain variability and land fragmentation.

Lines 249–255: The assumption of 0.65 MWp/ha as an average installable capacity is based on a single facility and literature references, but no data are shown. There is no validation of this figure for steep-slope vineyards or heterogeneous terrain, making the estimate unreliable.

Lines 267–273: Slope is treated as a categorical filter without justification for the selected thresholds or discussion of how slope classes interact with system design constraints. No modeling or simulation is provided to quantify the actual impact of slope on agrivoltaic performance.

Table 3: The table provides raw area data, but lacks any spatial or statistical validation. The absence of error margins or confidence intervals weakens the credibility of the presented values. NA values are reported but not explained or spatially contextualized.

Lines 288–294: The categorization of grape varieties is not supported by any physiological or agronomic data on varietal sensitivity to shading. No field data or published studies are cited to justify their classification in terms of agrivoltaic compatibility. The exercise is purely taxonomic and has no analytical value in the context of system feasibility.

Lines 308–311: The reported 44% feasibility figure is repeated from earlier sections without any analytical advancement. There is no uncertainty quantification, nor is the effect of interacting variables statistically assessed.

Lines 328–337: The justification for focusing on white grape varieties is based on unreferenced physiological assumptions. The exclusion of red varieties is not supported by data or shading response studies. Furthermore, the assumption that vines <10 years old are structurally adaptable is speculative and untested.

Lines 397–408: The argument linking vine age to PV planning is speculative and unsupported by data. No empirical basis is given for the supposed incompatibility of mid-aged vineyards, and no lifecycle cost modeling is provided.

Lines 418–421: The manuscript does not rigorously operationalize agronomic constraints. The spatial framework remains a simple overlay analysis without mechanistic modeling, scenario optimization, or probabilistic assessment.

Lines 428–435: The use of community-curated infrastructure data without any validation is a major methodological flaw. The reliance on unverified datasets for critical parameters like grid proximity renders the analysis speculative and undermines its practical applicability.

Lines 463–466:The model does not simulate energy production, shading, or financial returns. As such, its usefulness is limited to pre-screening. However, the manuscript fails to clarify the distinction between theoretical feasibility and actionable planning. The model remains descriptive, not predictive.

Lines 469–482: The practical implications are presented without supporting economic analysis. Key statements about regional corridor planning, cost-efficiency, and site selection are speculative and not supported by scenario-based financial modeling or stakeholder data.

Lines 506–517: The authors correctly identify the need for long-term trials but offer no novel insight. These statements are generic and expected. The manuscript would benefit from proposing specific experimental designs or performance indicators.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The document presents an interesting study of different factors that may influence the decision-making process of converting a vineyard into an agrivoltaic vineyard. The study is comparative in nature, as a Territorial Information System is used to assess the weight of nine factors.

The study considers only installations that feed the energy produced into the grid. It could be interesting to complement it by considering the possibility of direct delivery to industrial consumer centers through the establishment of PPAs. In this regard, the location  of industries and their evaluation as potential consumers would be of great interest.

Where possible, it would be advisable to include more quantitative information on the indicators that could assess the potential interest of current winegrowers in converting their farms into agrivoltaic ones.

The information related to some variables could be enriched by presenting histogram-type graphs that show the frequency distribution (relative or absolute) of the quantitative variables that have been evaluated.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

the topic is very intersting and actual, and you have investigated it from a very important point of view: potential of using agrivioltaics with regard to the slope and accessibility of the electrical grid. It is about research that will have to be carried out in other countries that implement or intend to implement Agrivoltaic technology. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Lines 144–151: The description of the geospatial evaluation framework is clear and technically sound. However, the section could be strengthened by providing more detail on the data preprocessing workflow in QGIS and Python,, which would improve reproducibility.

Lines 169–177: The proximity analysis between vineyard plots and grid points is well motivated. Still, the text should specify the exact thresholds used for classification (line 174) and provide justification for their selection, were they derived from technical standards, expert consultation, or economic cost modeling?

Lines 215–221: The exclusion of Natura 2000 areas is methodologically justified. However, I recommend the authors discuss whether buffer zones around protected areas were considered, as PV installations in close proximity may also raise ecological or regulatory concerns.

Lines 292–298: The finding that only 44% of vineyard area lies within 1,000 m of the grid is a critical insight. I recommend that the authors contextualize this figure by comparing it with results from other land-use sectors (solar parks, agrivoltaics in arable crops), which would demonstrate whether viticulture faces uniquely strong infrastructure constraints.

Lines 323–328: The categorization of grape varieties is comprehensive. However, since varietal shade tolerance is not explicitly modeled, the authors should clearly state that varietal selection in this framework is descriptive only, to avoid misinterpretation of the results as predictive of crop response.

Lines 332–338: The age distribution analysis provides valuable context for assessing retrofit opportunities. It would be helpful to link this directly to vineyard replanting cycles, perhaps with a reference to typical vine replacement rates in Rhineland-Palatinate, to ground the analysis in viticultural practice.

Figure A3: The figure depicting the frequency distribution of vineyard plots by scenario-based analysis is not clear in its current form. I suggest modifying it. 

Although the authors have undertaken an extensive revision of the manuscript, the study’s overall purpose and contribution remain unclear. While the introduction outlines the relevance of climate change, viticultural adaptation, and the potential role of agrivoltaics, the manuscript does not convincingly demonstrate how the proposed methodological framework addresses these challenges in a novel or impactful way. The objectives are stated, but they remain poorly linked to the findings, which are presented in a largely descriptive manner without a clear narrative on how they advance knowledge or inform decision-making in viticulture. To strengthen the manuscript, the authors must explicitly connect the motivations outlined in the introduction with the analytical outcomes, highlighting the scientific and practical significance of their results.

Author Response

Please see the attachment.

Kind regards,

Marcel Christ (on behalf of my co-author Prof. Dr. Moritz Wagner)

Author Response File: Author Response.docx