BIPV Market Development: International Technological Innovation System Analysis

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper delivers a comprehensive analysis of the current landscape and development barriers for Building-Integrated Photovoltaics (BIPV), applying the Technological Innovation System (TIS) framework. Drawing on TIS assessments from six countries (Sweden, Netherlands, Austria, Italy, Spain, and Australia), the authors evaluate BIPV from technical, regulatory, social, and market perspectives.

1. Include more recent TIS applications in energy transitions to show the broader academic context.
2. The manuscript references interviews with stakeholders but does not explain how interviewees were selected or how representativeness was ensured.
3. More detail on inter-rater reliability and how subjective scoring was standardized among countries would enhance credibility
4. A range of 250–450 MW is given for Europe without a clear reason for the uncertainty
5. Several references are self-citations
6. Change the style of the references based on the journals format

Author Response

Include more recent TIS applications in energy transitions to show the broader academic context.

• Thank you for pointing this out. Now six new examples and references of TIS applications in energy transitions have been added to section 2.2.

The manuscript references interviews with stakeholders but does not explain how interviewees were selected or how representativeness was ensured.

• Yes, thank you, we agree, the TIS process to gather the data and select the relevant stakeholders is now clarified in section 2.2.

More detail on inter-rater reliability and how subjective scoring was standardised among countries would enhance credibility.

• Thank you for your suggestion. The scoring methodology is now clarified in section 2.2.

A range of 250–450 MW is given for Europe without a clear reason for the uncertainty.

• The reasons are clarified in the same paragraph. The frequent confusion between BIPV and BAPV concepts and definitions (e.g., in some Feed-in-Tariff laws) and the diversity of BIPV products and manufacturers are the main reasons.  

Several references are self-citations.

•  Since the work is based on the main outcomes of six reports and other previous work by the authors, referencing these reports has been necessary. However, now there are 13 more references added from other authors, so the percentage of self-citations has been reduced.

Change the style of the references based on the journals format.

Thank you for the remark. Now references are supplied to the editor using Mendeley software, so that they can adjust the format properly.

 

Reviewer 2 Report

Comments and Suggestions for Authors

1. The current title "Insights into Building-Integrated Photovoltaics from Technological Innovation System Analyses" uses generic language that doesn't convey the specific research contribution. Remove "insights" and modify the title to reflect the main goal of the article. Every research article contains insights by nature, so this word adds no value. Suggested revision: "Building-Integrated Photovoltaics Market Development: A Comparative Technological Innovation System Analysis Across Six Countries" or "Barriers and Opportunities in BIPV Adoption: International Technological Innovation System Analysis."
2. The study examines only six countries with significant geographical bias (5 European countries vs. 1 non-European), yet makes global claims throughout. Location: Page 2, lines 77-78 and methodology section. Required action: Add a clear limitation statement explaining why the country selection was geographically constrained and discuss how this affects the generalizability of findings. Acknowledge that the European-heavy sample may not represent global BIPV innovation systems, particularly in major markets like China, India, or other developing economies where BIPV adoption patterns may differ significantly.
3. The paper presents precise numerical TIS function scores (1-5 scale) without adequate methodological transparency. Location: Page 4, Table 1 and Page 6, Figure 2. Specific problems: No information provided on: (a) the exact number of experts who scored each function per country, (b) inter-rater reliability measures between experts, and (c) statistical validation procedures for converting subjective expert opinions into precise numerical scores. Figure 2 displays scores like "Sweden=2.0, Italy=3.0 for social capital" but lacks explanation of how multiple expert opinions were aggregated into these specific values. This methodological gap undermines the credibility of all comparative analyses based on these scores.
4. The paper makes critical assertions about BIPV cost competitiveness without supporting quantitative analysis. Location: Page 6, lines 190-196 state "cost is more a matter of perception than an actual issue" and suggest "providing cases where BIPV is competitive would help increase the acceptance of BIPV." Critical flaw: No quantitative cost comparison data between BIPV and BAPV systems is provided to support this fundamental claim about cost barriers. Given that cost is identified as a primary adoption barrier throughout the paper, the absence of concrete cost analysis represents a major analytical gap that weakens policy recommendations.
5. The paper establishes causal relationships between TIS function scores and market performance without empirical validation. Location: Lines 213-222 state "Countries with higher BIPV entrepreneurial experimentation tend to have more diverse and active BIPV markets, which are closely tied to knowledge development, dissemination, and social capital." Critical flaws include: (a) No statistical analysis demonstrating correlation between TIS scores and actual market outcomes (market size, growth rates, adoption levels), (b) Claims of causality using language like "tend to have" and "closely tied" without empirical evidence, and (c) Figure 3 presents TIS function scores but lacks corresponding market performance data to validate these claimed relationships. These unsubstantiated causal claims undermine the theoretical foundation for policy recommendations.

Author Response

1. The current title "Insights into Building-Integrated Photovoltaics from Technological Innovation System Analyses" uses generic language that doesn't convey the specific research contribution. Remove "insights" and modify the title to reflect the main goal of the article. Every research article contains insights by nature, so this word adds no value. Suggested revision: "Building-Integrated Photovoltaics Market Development: A Comparative Technological Innovation System Analysis Across Six Countries" or "Barriers and Opportunities in BIPV Adoption: International Technological Innovation System Analysis."

Thank you for the remark. We have changed the title as suggested to “BIPV Market Development: International Technological Innovation System Analysis    "

2. The study examines only six countries with significant geographical bias (5 European countries vs. 1 non-European), yet makes global claims throughout. Location: Page 2, lines 77-78 and methodology section. Required action: Add a clear limitation statement explaining why the country selection was geographically constrained and discuss how this affects the generalizability of findings. Acknowledge that the European-heavy sample may not represent global BIPV innovation systems, particularly in major markets like China, India, or other developing economies where BIPV adoption patterns may differ significantly.

Thank you very much. These aspects are now clarified in lines 82-90.

3. The paper presents precise numerical TIS function scores (1-5 scale) without adequate methodological transparency. Location: Page 4, Table 1 and Page 6, Figure 2. Specific problems: No information provided on: (a) the exact number of experts who scored each function per country, (b) inter-rater reliability measures between experts, and (c) statistical validation procedures for converting subjective expert opinions into precise numerical scores. Figure 2 displays scores like "Sweden=2.0, Italy=3.0 for social capital" but lacks explanation of how expert opinions were aggregated into these specific values. This methodological gap undermines the credibility of all comparative analyses based on these scores.

A new paragraph has been added in lines 169-195 to clarify the scoring process.

4. The paper makes critical assertions about BIPV cost competitiveness without supporting quantitative analysis. Location: Page 6, lines 190-196 state "cost is more a matter of perception than an actual issue" and suggest "providing cases where BIPV is competitive would help increase the acceptance of BIPV." Critical flaw: No quantitative cost comparison data between BIPV and BAPV systems is provided to support this fundamental claim about cost barriers. Given that cost is identified as a primary adoption barrier throughout the paper, the absence of concrete cost analysis represents a major analytical gap that weakens policy recommendations.

Thank you for addressing this important point. To illustrate the costs quantitatively, costs for regular PV modules and BIPV modules are now presented from different sources (IEA PVPS National Survey Reports and Fraunhofer Institute report and IRENA report), along with a reflection about the non-convenience of not considering the dual role of BIPV modules and systems when analysing costs (lines 246-260).

5. The paper establishes causal relationships between TIS function scores and market performance without empirical validation. Location: Lines 213-222 state "Countries with higher BIPV entrepreneurial experimentation tend to have more diverse and active BIPV markets, which are closely tied to knowledge development, dissemination, and social capital." Critical flaws include: (a) No statistical analysis demonstrating correlation between TIS scores and actual market outcomes (market size, growth rates, adoption levels), (b) Claims of causality using language like "tend to have" and "closely tied" without empirical evidence, and (c) Figure 3 presents TIS function scores but lacks corresponding market performance data to validate these claimed relationships. These unsubstantiated causal claims undermine the theoretical foundation for policy recommendations.

We agree with your comments. The sentence has been changed to: “In general, higher BIPV entrepreneurial experimentation leads to more diverse and active BIPV markets, which are closely tied to knowledge development, dissemination, and social capital. Austria, Italy and the Netherlands have shown a moderate fulfilment of this function.”

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Author,

I encourage you to carefully review your manuscript once again and consider refining some of your findings, particularly those highlighted in comment number 5.

In several instances, the claims appear too broad given that the study is based on a single case. For example, your title and certain sections of the text refer to global matter, yet the empirical basis remains limited to one context. While it is common in academic research to draw inferences from case studies, it is important to present such inferences with appropriate caution.

I recommend moderating the language around impact and effects to better reflect the scope and limitations of your study.

Best regards,

Author Response

I encourage you to carefully review your manuscript once again and consider refining some of your findings, particularly those highlighted in comment number 5. In several instances, the claims appear too broad given that the study is based on a single case. For example, your title and certain sections of the text refer to global matter, yet the empirical basis remains limited to one context. While it is common in academic research to draw inferences from case studies, it is important to present such inferences with appropriate caution. I recommend moderating the language around impact and effects to better reflect the scope and limitations of your study.

Thank you for emphasising this point. The title may suggest that the study has a broad international scope, implying the inclusion of multiple representative countries. However, the introduction clearly states that the geographical focus is primarily on European countries. The results and conclusions sections also make it explicit that the analysis is based on data from six specific countries.

To further clarify the context, we have now added more detailed explanation (lines 232–239) regarding the link between Italy’s higher level of entrepreneurial activity and its BIPV market development.

Although the core analysis focuses on these six countries, the document occasionally references other nations to provide a broader perspective on global BIPV trends. For instance, China is mentioned as an emerging BIPV market (lines 305–307), and Germany and France are noted for their specific support mechanisms for BIPV (lines 571–574). Additionally, global market data is included to help contextualise the findings (lines 280–288).

All relevant additions and clarifications are highlighted in yellow. English has also been improved.