Environmental Impact Assessment of Nesjavellir Geothermal Power Plant for Heat and Electricity Production
, Maryori Díaz-Ramírez 1,2, Snorri J. Egilsson 3, Claudio Zuffi 4, Giampaolo Manfrida 4 and Héctor Leiva 1Round 1
Reviewer 1 Report
The paper assesses the environmental performance of the Nessjavellir Geothermal Power Plant (GPP) in Iceland and explores the implementation of an abatement system to reduce CO2 and H2S emissions. By employing a life cycle assessment methodology, the research reveals that the environmental impact is notably influenced by the construction phase of the Nessjavellir Geothermal Power Plant. The research highlights the importance of considering the entire life cycle of the GPP and emphasizes the potential environmental benefits of the abatement system.
The key areas of improvement for the paper are outlined below:
1) The manuscript doesn't go deep into the costs or potential returns of using presented technology.
2) The benefits of the abatement system are clear, but an actionable strategy for real-world implementation is absent.
3) The paper doesn't provide a comparative analysis with other existing geothermal technologies.
Author Response
Dear Reviewer,
Firstly, we would like to express our sincere gratitude for your comments and suggestions, which have contributed to improve this new version of the manuscript. Detailed responses to the reviewer comments can be found below (red lyrics on the word file). The authors hope that the editorial board and the reviewer will agree with the authors’ responses and accept this revised version of the manuscript.
Your sincerely,
Author Response File: 
Author Response.pdf
Reviewer 2 Report
You present an interesting work with encouraging results. Personally I have a question:
You mention that the scrubber uses a lot of freshwater. Would it be an option to use waste water instead?
Please be careful (and never mix up) the two different quantities in physics: “power” and “energy”. The first has the unit of Watt (W, kW…) the second one has the unit of Joule (1J=1W.s) alternatively WattHours (Wh, kWh …) may be used. You find several examples of “how not to do it” in the abstract. For instance in Line 27: “...kilowatt of thermal energy.”
Is it “Nesjavellir Power Plant” (line 71) or “Nessjavellir GPP” (line 80) ?
Line 121 “.. diagram presented in Figure 2 shows the two-phase flow..”, I think you mean Fig.1
Line 202 “? Tf Is the installed electricity capacity (MW)” ? The electricity capacity was already defined in Line 198 using the symbol Pn,e
Line 232: “ … it was assumed 1% machinery component replacement”. Is this the percentage during the 30 years of operation or is it meant for 1 year ?
Fig.8 Shows two column-comparisons for the externalities both referred to the electric system? I think one should be for the heating system.
Line 424: Please add WTP to your list of the nomenclature
Line 447, Table A5 ????
Line 461: “(Error! Reference source not found.)” ?
Line 476: The symbol should be the lower case letter: n
The manuscript is easy to read. Some ,formatting errors exist.
Author Response
Dear Reviewer,
Firstly, we would like to express our sincere gratitude for your comments and suggestions, which have contributed to improve this new version of the manuscript. Detailed responses to the reviewer comments can be found below (red lyrics on the word file). The authors hope that the editorial board and the reviewer will agree with the authors’ responses and accept this revised version of the manuscript.
Your sincerely,
Author Response File: Author Response.pdf
Reviewer 3 Report
I have minor comments: It is better if the author can provide a figure of the supply chain of producing 1 kWh.
The LCA methodology considers the entire life cycle of the geothermal power plant, including the upstream processes required to extract and produce the raw materials used in its construction. This means that the environmental impacts associated with mining, processing, and transporting the raw materials, such as steel, concrete, and other construction materials, should take into account by the author during the assessment of raw material extraction."
Author Response
Dear Reviewer,
Firstly, we would like to express our sincere gratitude for your comments and suggestions, which have contributed to improve this new version of the manuscript. Detailed responses to the reviewer comments can be found below (red lyrics on the word file). The authors hope that the editorial board and the reviewer will agree with the authors’ responses and accept this revised version of the manuscript.
Your sincerely,
Author Response File: Author Response.pdf
Reviewer 4 Report
11) Authors should check equation 1 and variables’ definition
22) Figure 5, the exceptions: it should me mentioned more 2 impact categories (TAP and PMFP)
33) Table2,3,4, 5 need some more information as the units don’t seem to be right; total(/kWhe)? It is necessary to explain the economic value conversion factor.
Some sentences can be improved.
ex.: . When including the 330 CarbFix abatement system to remove CO2 and H2S from the NCGs emitted by Nessjavellir 331 GPP, the environmental impacts results evaluated for the baseline scenario change.
Author Response
Dear Reviewer,
Firstly, we would like to express our sincere gratitude for your comments and suggestions, which have contributed to improve this new version of the manuscript. Detailed responses to the reviewer comments can be found below (red lyrics on the word file). The authors hope that the editorial board and the reviewer will agree with the authors’ responses and accept this revised version of the manuscript.
Your sincerely,
Author Response File: Author Response.pdf
