Assessing International Technological Competitiveness in Renewable Energy: An IPC-Based Analysis of Granted Patents

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study has two main goals. First, it uses IPC-coded granted-patent data to compare how leading countries perform across the renewable-energy field and within four subsectors—solar, wind, geothermal, and hydro (called water in this paper). Second, the authors blend patent counts with technology-portfolio mapping to offer a broader view than numbers alone can give. The manuscript reads well overall, but several points need sharper explanation and more up-to-date evidence.

Overall Comments

• Patents alone don’t capture innovation. For instance, “Patents Do Not Measure Innovation Success” (DOI 10.1561/104.00000087) notes low use rates, modest disruptiveness, and uneven quality. Please consider that patent examiners check novelty and enablement, not real-world feasibility or market value. Flag this difference from peer review.
• Renewable performance is location-dependent (resource quality, grid limits, policy). Please acknowledge these regional factors.
• Please provide a table translating every IPC code into plain-language technology labels.
• Dropping bioenergy overlooks biogas and biomass, which are major, IPCC-recognized, carbon-neutral options in many places.
• Batteries and broader energy-storage systems are essential to renewables. Their absence weakens the competitiveness map.

Specific Comments

• Line 62 The claim that patents are an “objective lens” relies on a 2013 source. Please add newer work that supports or challenges this idea.
• Lines 63–65 Reference [21] calls patents a proxy, not a standard. Adjust wording or justify treating the proxy as definitive.
• Section 2.1 Consider human-capital data (STEM graduates, researcher density, digital skills), digital infrastructure, adoption rates, and financing indicators.
• Line 214 Explain why the study chose only these four renewables.
• Line 243 Excluding bioenergy ignores biogas and biomass pathways that cut methane and CO₂ and are classed as carbon-neutral by the IPCC.
• Line 243 Use “solar-energy technologies” instead of “solar power” to include solar-thermal uses.
• Line 247 If “water” means hydropower, use “hydro” for clarity.
• Table 1 List full IPC codes so readers can see exactly which technology families were counted.
• Line 414 Keep “water” patents to hydro classes; codes like E02B and B63H cover flood control and ship drives, not power generation.
• Figure 8 Add a legend explaining PA and PQ.
• Line 492 Steam turbines appear in geothermal, biomass, solar-thermal, and fossil plants. Explain how the analysis isolates geothermal uses.
• Line 498 F03B covers Organic Rankine Cycle devices, not just water-driven machines. Check that only hydro-relevant patents were included.
• Lines 587–589 This conclusion fits only the countries studied. Note that each RE plan must match local natural resources, market penetration, and countries technology capabilities.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Decision: Accept with Minor Revisions

Dear Authors,

Thank you for submitting your manuscript titled "Assessing International Technological Competitiveness in Renewable Energy: An IPC-Based Analysis of Granted Patents." After careful review, I find that your paper makes a significant contribution to the field of renewable energy and patent analysis, offering valuable insights into technological competitiveness across key nations.

Your methodology combining patent and technology portfolio analyses, along with the long-term dataset from 1975 to 2024, provides a well-rounded view of global trends in renewable energy technologies. The findings regarding solar, wind, geothermal, and water energy are of great importance, particularly for policymakers, industry stakeholders, and researchers.

However, to enhance clarity and strengthen the paper, I request that you make minor revisions. Once these revisions are made, I believe your paper will be in excellent shape for publication.

Thank you again for your contribution, and I look forward to your revised submission.

Sincerely,

Best regards,

Reviewer

 

My Comments

 

 

1. (Lines 11-12): The phrase "climatechange mitigation and carbonemission reduction becoming critical international priorities" could be simplified for brevity, e.g., "with climate change mitigation and carbon emission reduction as global priorities.
2. (Lines 13-14): Consider specifying the five major energy powers to clarify the geographical focus of the study.
3. (Lines 16-17): It would be helpful to briefly mention the specific metrics or methods used in the patent portfolio analysis to enhance understanding of the methodology.
4. (Lines 25-27): The final sentence could provide more details on how the findings will directly guide policymakers and industry stakeholders in their decision-making.
5. The keywords list includes terms that are redundant (e.g., "Technology Portfolio Analysis" and "Patent Portfolio Analysis") and others that are too broad (e.g., "Granted Patent," "Sustainability Strategy"). Consider streamlining the list by focusing on the most relevant and specific terms, such as "Renewable Energy," "Technological Competitiveness," and key energy technologies (e.g., "Solar Energy," "Wind Energy"). This will help improve searchability and relevance.
6. (Lines 34-36): The phrase "many countries now regard the expansion of renewable energy as a core strategy" could be simplified to "many countries consider renewable energy expansion a core strategy.
7. (Lines 49-54): The introduction is well-structured, but the connection between technological competitiveness challenges and the need for patent analysis could be made clearer. Consider explicitly stating how patent data addresses these challenges earlier.
8. (Lines 72-74): The explanation of using granted patents and the IPC system is clear, but adding more detail on why the IPC system is superior to other patent classification systems could strengthen this argument.
9. (Lines 50-66): The references to prior studies are helpful but could briefly mention the key findings from those studies to highlight how your work builds on them and fills any gaps.
10. Lines 87-94): The study’s objectives are well-defined. However, more emphasis on how merging patent and technology portfolio analyses offers new insights compared to previous studies would make the contribution clearer.
11. (Lines 107-112): The description of "technological competitiveness"could be slightly refined. For example, instead of saying, "commonly gauging it by R&D investment levels, publication counts, patent applications, and grant statistics," consider saying, "commonly measured through indicators such as R&D investment, publication counts, patent applications, and grant statistics.
12. (Lines 125-137): The section outlines various methods of evaluating technological competitiveness but lacks a clear connection between each method and its limitations. Consider better linking the discussion of methods to the paper’s approach, showing how these limitations justify the use of patent and technology portfolio analyses in the study.
13. (Lines 146-149, 166-169): While the introduction of different models (e.g., Ernst's two-dimensional model, Porter’s Diamond Model) is useful, it might be beneficial to provide a brief comparison between them and explain how your study improves upon or builds on these methods.
14. (Lines 158-164, 179-185): The limitations of previous research, such as the over-reliance on keyword searches or focus on broad technological areas, are clearly highlighted. However, expanding on how your methodology specifically addresses these gaps in a bit more detail would strengthen the argument for your approach.
15. (188-199): The discussion about gaps in renewable energy technology analysis is insightful. However, emphasizing how your study fills these gaps by providing both industry-wide and subsector-specific technological analyses earlier in the section would strengthen the transition to your research objectives.
16. (Lines 205-215): The description of the three-step research procedure (trends analysis, patent portfolio analysis, and technology portfolio analysis) is clear. However, a brief summary of how these steps connect to provide a comprehensive assessment of technological competitiveness would strengthen the flow between sections. Consider adding a sentence at the end of the paragraph linking the steps to the overall goal of the study.
17. 219-226): The decision to use WIPS ON for data collection is well-explained, but the comparison to other databases like USPTO and EspaceNet could be slightly expanded to clarify why WIPS ON is preferable for this study. While the benefits are mentioned, more explicit reasoning behind the choice (e.g., database completeness, coverage, ease of access to specific fields) would improve transparency.
18. (Lines 237-249): The classification of technologies based on IPC codes is clearly articulated. However, the explanation could benefit from a brief mention of any challenges encountered during the classification process, such as handling ambiguous or overlapping IPC codes, and how these challenges were addressed.
19. (Lines 259-263): The selection of the five nations (United States, EU, Japan, China, and Korea) is justified, but a brief explanation of why these specific countries were chosen would help contextualize their role in the study. For example, mentioning their global influence in renewable energy or innovation would add depth to the rationale.
20. (Lines 270-280): The stepwise procedure for trends analysis is well-structured. However, consider briefly explaining how the "surges" and "shifts in relative standing" will be quantified, as these terms may benefit from more explicit definitions or examples.
21. (Lines 282-327): The procedures for patent portfolio analysis and technology portfolio analysis are detailed and clearly differentiate between the two. To improve clarity, you might want to emphasize the specific advantages of using both methods together. How does combining them offer unique insights that individual methods cannot?
22. (Lines 335-339): The description of the increase in patents after 2010 is clear. However, the phrase “surge in 2024 underscores renewed momentum” could be elaborated to explain any underlying factors or trends that may have contributed to this surge. For example, was this surge due to new innovations, changes in policy, or international collaborations?
23. (Lines 341-353): The trend data is presented well, but the introduction of intervals in Table 4 could benefit from a brief explanation of why these specific periods were chosen and what they represent in terms of technological or policy shifts. More context could help clarify why particular years (e.g., 2020–2024) saw such dramatic increases.
24. (Lines 363-374): The country-specific trends are effectively summarized. However, it would be helpful to clarify why some countries like China and the United States have a dominant presence in solar and wind patents. Are there particular policies or technological breakthroughs driving these trends? Providing a bit more context on the drivers behind these trends would add depth to the analysis.
25. (Lines 385-419): The analysis of technology-specific trends is thorough, but some technologies, such as H01L semiconductor-based solar cells and F03D wind-turbine tech, are discussed in detail. It would be helpful to briefly explain why these technologies were selected for in-depth analysis and how they represent the broader technological shifts in each sector.
26. (Lines 350-361): The data in Tables 4 and 5 is clear, but it would be helpful to explicitly reference how these figures tie into the earlier narrative of technological growth trends. For instance, how does the volume of solar patents correlate with the R&D investment or specific technological advancements?
27. (Lines 425-505): The detailed analysis of patent portfolios and technology-specific trends provides important insights. However, it would benefit from a clearer distinction between patent activityand patent quality in your explanations. How do these two aspects correlate with each country's overall technological competitiveness, and what implications do these differences have for future R&D and industrial strategies?
28. Lines 509-513): The discussion does a good job of summarizing key findings, particularly the surge in renewable energy patents after 2010. However, the connection between the sharp increase in patent filings and global initiatives (e.g., RE100and carbon neutrality commitments) could be made clearer. A brief explanation of how these global initiatives directly influenced patent filings would add depth to the argument.
29. (Lines 514-519): The differentiation between solar, wind, geothermal, and watertechnologies in terms of patent volumes is well-done. However, it would be helpful to mention how patent volumes directly relate to technological maturity or innovation in these sectors. For example, does the volume of patents correlate with breakthroughs in technology or are they mainly incremental innovations?
30. (Lines 523-531): The analysis of patent distribution across IPC tiers is useful, but the text could be more specific about the implications of these findings. For instance, how do these distribution patterns correlate with the success or failure of technologies in the market? Providing an example of a specific technology that stands out in its IPC distribution could strengthen this point.
31. (Lines 532-541): The discussion of country-level competitiveness is insightful. However, a more direct connection between the quality indicators and the long-term technological leadership of each country could be made clearer. For example, does China’s large patent volume indicate future dominance, or does the lack of depth in its patent quality suggest vulnerabilities in the long run?
32. (Lines 544-555): The identification of core technologies across energy sources is a strong point, but more emphasis on why these technologies were chosen and their potential impact on future energy systems would add more depth. For example, why are semiconductor-based solar cells (H01L) seen as particularly critical in the context of global competition?
33. (Lines 548-561): The discussion of different national strategies (e.g., China’s rapid expansion, Europe’s focus on high-value applications, Korea and Japan’s niche strategies) is excellent. However, it would be beneficial to mention the potential risks and rewards associated with each approach. For example, could China’s strategy of quantitative expansion lead to future issues with technological depth or innovation quality?
34. (Lines 564-575): The conclusions provide a good summary of the study's findings. However, it might be helpful to explicitly mention the key implications for each of the regions or countries analyzed (e.g., specific recommendations for the United States, China, Europe, etc.) rather than a general overview. This would add more specificity to the conclusion, making it clearer how the results directly impact each region's strategic decisions.
35. (Lines 576-583): The discussion of the dynamic nature of the solar and wind sectors versus the steadier advancements in geothermal and water sectors is well-done. To enhance this, it would be beneficial to briefly mention what specific characteristics (e.g., market demand, technological innovation, government policy) contribute to these different trajectories, as this could help guide future R&D investments more effectively.
36. (Lines 585-589): The conclusion suggests that the results offer a basis for policymakers to align R&D with global patent trends. This is valuable, but it could be further strengthened by suggesting specific actions. For example, what types of international collaborations or investments should be prioritized to accelerate the energy transition?
37. (Lines 590-594): The recommendations for firms and research institutions are strong. However, the point about adjusting R&D roadmaps and pursuing technology transfers could be elaborated further by providing examples of strategies or partnerships that could facilitate this process, helping companies and institutions act on these insights.
38. (Lines 595-602): The suggestion for future work to incorporate additional R&D indicators and evaluate the market effectiveness of innovations is excellent. To strengthen this point, it might be helpful to specify potential methods or data sources for incorporating AI, IoT, and other emerging technologies into future competitiveness assessments, providing a clearer roadmap for future research.
39. (Lines 646-857): Some references are missing crucial information such as publisher names for books or missing article titles. Ensure that all references, especially those to books and reports, provide full citation details. For example, references like Archibugi & Pianta (1992) should have complete information about the publisher, while journal articles should have consistent formats for volume and issue numbers
40. (Lines 646-857): There are multiple entries that seem to refer to the same or very similar works, such as multiple entries by Ernst (2003, 2011, 1998) and others. Ensure that these references are not repeated unnecessarily, and that they are accurately cited with distinct entries.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The proposed research is of significant interest. Conducting a macroeconomic comparative analysis of the technological positioning of five countries in the field of renewable energy represents a highly relevant empirical approach, providing valuable insights into the dynamics of ecological transition efforts.

One of the undeniable strengths of the article lies in the richness of its results across three levels of analysis: comparison between energy types, between countries, and for each country, among the specific technological subcategories within each energy domain.

Despite these clear strengths, several improvements are necessary to enhance the clarity, rigor, and interpretability of the study:

• Period of analysis:
  While covering a long time span offers useful historical perspective, comparing China’s patent statistics with those of the U.S., Japan, and Europe before the 1990s is problematic due to the underdeveloped state of China’s intellectual property system at that time. This biases the analysis against China. A clearer segmentation of the study period is strongly recommended (e.g., 1975–2004, 2005–2014, 2015–2024). The current overlapping segmentation (1975–2004, 1975–2014, 1975–2024) leads to confusion and undermines the relevance of the comparisons.

 

• Methodology presentation:

While the overall method is understandable, several specific clarifications are needed:

• • Patent corpus definition: The process used to construct the patent dataset for each of the four energy types lacks transparency. What criteria were used to identify the classification codes? Did the authors rely on established schemes such as WIPO’s IPC Green Inventory? Was any expert validation process implemented? Furthermore, a manual validation step is mentioned (line 284: “by filtering the pool...”), which needs to be clearly explained.

  • Country attribution of patents: It is essential to clarify whether patents were assigned based on filing office or applicant nationality. For a study on national technological competitiveness, using applicant nationality is more appropriate and avoids double-counting patents filed in multiple jurisdictions.

  • Calculation of quality and quantity scores: The rationale behind the scoring matrices (ranging from 0 to 5 or 0 to 8) is not sufficiently explained. How were these scores calculated? What formulas were used? How were thresholds for the quadrants determined (e.g., threshold of 3 for PQ, 1 for P1)?

  • Quadrant interpretation: The interpretation of the quadrants in both matrices should be more detailed, particularly the bottom-right quadrant ("activities") in the patent portfolio matrix.

• Methodological choices:
  The study would benefit from including established indicators of technological specialization, such as the Revealed Technological Advantage (RTA) index, which is commonly used in patent-based analyses. The authors could refer to recent work such as Mora-Apablaza & Navarrete (2022, Scientometrics), who propose both basic and advanced versions of this index to assess countries' technological positions.

General comments:

• • The peak in patent counts for 2024 is surprising, considering the average patent granting time (e.g., around 5 years in Europe). This anomaly should be reviewed.

  • Finally, the numerous figures and visualizations are difficult to interpret as they currently stand. Additional explanatory notes or legends would help the reader. As it stands, some of the authors' conclusions appear unjustified given the presented data.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Dear authors,

Thank you for considering my comments and suggestions for improvement. I wish you continued success in your work.

 

Best regards,