The GHG Intensities of Wind Power Plants in China from a Life-Cycle Perspective: The Impacts of Geographical Location, Turbine Technology and Management Level

Round 1

Reviewer 1 Report

This study presents a comparative life cycle assessment of 60 case wind plant systems erected in China. Concerning different resource endowments, turbine technology and management level. The author estimates the different life-cycle GHG emissions and analyzes their changes in different resource endowments, turbine technology and management level by applying the process-based LCA method to multiply case plants.

It is a well-organized paper. The results and conclusion seem to be reasonably correct.

Concern # 1: The principal results and major conclusions are missing in the abstract. Add some of the main contributors to the GHG emissions for selected cases.

Concern # 2: The resolution of figure 1 is not good and should be addressed.

Concern #3: Avoid the abbreviation in the subsection titles such as 2.2.3,2.2.4 and 2.2.5.

Concern # 4: some figures are before the explanations, while some of them are after the description. Please, decide on the same position (before or after the description for all figures.

Concern # 5: Line 86: Please, reference the ISO norms.

Concern # 6: English writing must be carefully revised. A complete edit by an English-speaking professional is necessary. There are extensive grammatical, structural, and write-up problems throughout the manuscript.

In summary, the authors need to revise the manuscript by incorporating all the Concerns and it should be treated as a minor revision.

Author Response

Reviewer 1

Concern # 1: The principal results and major conclusions are missing in the abstract. Add some of the main contributors to the GHG emissions for selected cases.

Author’s Reply: We reconstruct the structure of the abstract and the conclusions, not only adding the quantitative results into it, but also for making it entirely much more logistic. In this study, we discuss the GHG intensities in a life-cycle perspective from wind resource, turbine technology and wind curtailment. Based on these three factors, our principal results and major conclusions involve the relationships between the GHG intensities and the factors, and further put the factors into sub-factors for analysis.

Concern # 2: The resolution of figure 1 is not good and should be addressed.

Author’s Reply: For the problem on the resolution of the figures in this study, it is necessarily stressed that they are drawn by software Visio (figure 1) and Origin (other figures), and thus have absolutely high resolution. However, it is exactly a fact that parts of words in the figure cannot be easily discriminated, so we have adjusted the font in order to make it clearer to be read.

Concern # 3: Avoid the abbreviation in the subsection titles such as 2.2.3,2.2.4 and 2.2.5.

Author’s Reply: We have revised “vs.” into “versus”.

Concern # 4: some figures are before the explanations, while some of them are after the description. Please, decide on the same position (before or after the description for all figures).

Author’s Reply: Actually, whether all figures unfitly put on the same position (before or after the description) is not our main concern, but the appropriate position is more important. We think the position of these figures play a role vital in conveying core thought of this study, and it did. Therefore, there is no reason changing that.

Concern # 5: Line 86: Please, reference the ISO norms.

Author’s Reply: Sure, we have referenced the ISO norms as you suggest.

Concern # 6: English writing must be carefully revised. A complete edit by an English-speaking professional is necessary. There are extensive grammatical, structural, and write-up problems throughout the manuscript.

Author’s Reply: Because not from English-native countries, we exactly have problems on the grammar and structure about writing. Focused on these problems, this manuscript has been revised on its structure and grammar mistakes.

Reviewer 2 Report

·       The paper conducts life cycle analysis of wind power plants in China and examines the role of certain decision parameters, namely wind resource availability, turbine technology, and curtailment, on the results. The authors deployed processed-based LCA (or bottom-up LCA)

·       The manuscript is well written and covers all aspects of an LCA work. I don’t have major comments except a few minor points mentioned below:

·       The system boundary is claimed to be cradle-to-gate (Line 158) of the whole plant, but the authors still includes EoL phase of different components. This needs to be rephrased to avoid any ambiguity. How does EoL of individual components differ from that of plant? Isn’t plant composed of these components?

·       The system boundary excludes (Line 179-183) the impacts of transmission system. While it is a reasonable assumption, it might be useful to indicate possible percentage contribution of the transmission system to the overall impacts of the wind plant. This will help the reader in putting the assumptions in broader perspective.

Author Response

Reviewer 2

Concern # 1: The system boundary is claimed to be cradle-to-gate (Line 158) of the whole plant, but the authors still includes EoL phase of different components. This needs to be rephrased to avoid any ambiguity. How does EoL of individual components differ from that of plant? Isn’t plant composed of these components?

Author’s Reply: Thanks for your complementary and suggestion. We stress out using LCA method to analyze the GHG intensities of wind power plants in China, but ignore the detailed explanation on the important concept of system boundary. From the whole life-cycle perspective, this study is based on the framework of cradle-to-grave considering the recycling materials (the net GHG emissions), which is crucial to analyze the contribution of each phase to the GHG intensity, and we further divide it into “cradle-to-gate”, which excludes the recycling materials (the total/life-cycle GHG emissions). Totally, we discuss the GHG intensities of wind power plants primarily from “cradle-to-gate” boundary, and system boundary have been revised.

Concern # 2: The system boundary excludes (Line 179-183) the impacts of transmission system. While it is a reasonable assumption, it might be useful to indicate possible percentage contribution of the transmission system to the overall impacts of the wind plant. This will help the reader in putting the assumptions in broader perspective.

Author’s Reply: At present, limited researches have been carried out using LCA for wind power transmission system, but only for offshore, because of its high environmental cost during the construction and installation of transmission. However, the impacts of transmission system have not been considered in our study is because that 1) this field is still a gap, especially for onshore wind power plants, and this issue should be compressively discussed; 2) although the relative research on offshore have been finitely conducted, but case-specific study in China have been not extensively considered in the previous studies.